Book of Abstracts
5th International Sclerochronology Conference
16-20th June 2019 Split, Croatia

Book of Abstracts
5th International Sclerochronology Conference
16-20th June 2019 Split, Croatia

5th International Sclerochronology Conference, ISC 2019

Conference Chair
Melita Peharda, Institute of Oceanography and Fisheries, Croatia

Scientific Committee
Meghan Burchell, Memorial University, Canada
Paul G. Butler, University of Exeter, UK
Michael Carroll, Akvaplan-niva, Norway
John R. Morrongiello, The University of Melburne, Australia
Yuji Sano, The University of Tokyo, Japan
Bernd R. Schöne, Johannes Gutenberg University, Germany
Kotaro Shirai, The University of Tokyo, Japan
Julien Thébault, University of Brest, France
Alan Wanamaker, Iowa State University, USA

Organisation Committee
Daria Ezgeta-Balić, Institute of Oceanography and Fisheries, Croatia
Damir Ivanković, Institute of Oceanography and Fisheries, Croatia
Krešimir Markulin, Institute of Oceanography and Fisheries, Croatia
Sanja Matić-Skoko, Institute of Oceanography and Fisheries, Croatia
Mirela Petrić, University of Split, Croatia
Hana Uvanović, Institute of Oceanography and Fisheries, Croatia
Ivica Vilibić, Institute of Oceanography and Fisheries, Croatia
Dario Vrdoljak, Institute of Oceanography and Fisheries, Croatia
Ivan Župan, University of Zadar, Croatia

Local support Team
Tomislav Džoić, Institute of Oceanography and Fisheries, Croatia
Mišo Pavičić, Institute of Oceanography and Fisheries, Croatia
Jasna Šilljić, Institute of Oceanography and Fisheries, Croatia

Abstract Volume
Editors: Melita Peharda, Daria Ezgeta-Balić, Hana Uvanović
Institutute of Oceanography and Fisheries

Recommended citation: Peharda, M., Ezgeta-Balić, D., Uvanović, H. (Eds). 2019. 5thInternational Sclerochronology Conference, 16-20th June 2019, Split, Croatia. Book of
Abstracts.
Copyright and responsibility for the scientific content lie with thecontributing authors.
Cover photo by Mišo Pavičić, Split, Croatia
15th International Sclerochronology Conference, ISC 2019
Dear Friends and Colleagues,
On behalf of the Conference Organising Committee we would like to welcome you to thebeautiful City of Split and to the 5th International Sclerochronology Conference (ISC2019)organized by the Institute of Oceanography and Fisheries (www.izor.hr).
This Conference marks a small jubilee – scientists and students interested in sclerochronology
gathering together for the fifth time. Since the first International Sclerochronology Conferencein St. Petersburg, Florida in 2007, our sclerochronology community has grown both in numbers
and geographically. This conference in Split covers research conducted on all the continents,from the traditionally well represented Europe and North America, to Asia, Australia, Africa,
South America, and even Antarctica. We wish a warm welcome to all of you traveling fromnear and far, and thank you for taking the time to participate in ISC2019.
Special thanks to our keynote speakers: your experience and viewpoints give direction to oureight conference sessions. Coming from a research institute with a strong fisheries
component, we are especially pleased that the session on Fisheries Ecology and Management
has generated such great interest and that fish-based research has also been included inseveral other conference sessions. The need for organising a conference that would gather
scientists interested in bivalve shells and fish otoliths, arose at the ISC2013 in Wales, and weare proud to have achieved this. Based on your submissions and interest, one of the main
challenges faced by the sclerochronology community is the commercial application of ourresearch, and this is certainly something that we should address in the future. The researchpresented at the ISC2019 is highly diverse with respect to topics and taxa and we hope thatyou will have a productive meeting resulting in new international and interdisciplinary
collaboration.
Work hard, play hard. And Split is a great place for all this. The conference venue is Faculty of
Medicine, University of Split, located about 10 minutes from the nearest beach (possible lunch
break swim) and just under 30 minutes to the city centre by foot (of course, public
transportation and taxis are available). Split has a rich history and cultural heritage – with the
1700-year old magnificent Diocletian’s Palace at its very heart. Riva - the seafront promenadein the centre, Peristil Square in front of St. Domnius’ Cathedral and the Bačvice sandy beachare just a few of the spots you should certainly visit while in Split. Croatia has excellent olive
oil, cheeses, fish - so do not forget to enjoy your evenings in town and take home some ofthese flavours. We have a great conference and social programme set up for you and hopethat your time in our city will have unforgettable.
Preparations for this conference were conducted within the framework of SCOOL and
NurseFish projects financed by the Croatian Science Foundation.
We would especially like to thank our sponsors and the members of the Scientific Committees
who contributed to the conference organisation and made this possible.
Hvala,
Organising Committee
25th International Sclerochronology Conference, ISC 2019

The organizers of ISC 2019 are very thankful for the support of the following sponsors.

Platinum sponsors
Institute of Oceanography and Fisheries, Split, Croatia
Faculty of Medicine, University of Split, Croatia
Department of Ecology, Agronomy and Aquaculture, University of Zadar, Croatia

Gold Sponsor
Nu Instruments, United Kingdom
Struers – Ensuring Certainty

Silver Sponsor
A.E. Lalonde AMS Laboratory, Ontario, Canada
Marine Studies Group, The Geological Society of London, United Kingdom
Stable Isotope Facility, UC Davis, California, USA35th International Sclerochronology Conference, ISC 2019

Keynote presentations
Presenting authors are listed below in alphabetical order with abstract titles (pages 17-24).
Bryan A. Black
Towards an integrated synthesis of Earth’s coupled marine-terrestrial systems
Steven Campana
A view into the abyss; have we seen the limits of sclerochronology?
Antonio Checa
Direct cellular activity drives the fabrication of some invertebrate microstructures
David P. Gillikin
Bivalve sclerochemistry: challenges and opportunities
Peter Grønkjær
Elements, isotopes and banding patterns – Sclerochronogical approaches to the study physiological
performance in fishes
Linda C. Ivany
How low can you go? Seasonal resolution in 300-million-year-old aragonite mollusks and the insights
they provide
Karin Limburg
Environmental biomonitoring – challenges for sclerochronologists
Amy Prendergast
Sclerochronology and archaeology in the Mediterranean: seasonal foraging patterns, environmental
change, and human-environment interaction

45th International Sclerochronology Conference, ISC 2019

Oral presentations
Presenting authors are listed below in alphabetical order with abstract titles (pages 26-97).
Stella J. Alexandroff
Hydrographic and climate variability at St Kilda, Scotland, since the late 19th century
C. Fred T. Andrus
Challenges and applications of oxygen isotope analysis of season of capture of freshwater mollusks
Christine N. Bassett
Fact or Fiction? Exploring the possibility of Neoglacial sea ice off the coast of Unalaska
Justine Briard
Seawater paleotemperature and paleosalinity evolution in neritic environments of theMediterranean margin during the Miocene: insights from combined δ18O-Δ47 analyses of bivalve
shellsWilliam M. Brocas
Corals reveal a cooler and fresher tropical Atlantic during the mid-last interglacial
Deirdre Brophy
Reconstructing growth histories across multiple fish species in the Celtic Sea using multidecadalotolith collections
Meghan Burchell
Shell midden archives, climate change and human response in Barkley Sound, British Columbia
Pierluigi Carbonara
An ecological perspective of age and growth in Mullus surmuletus Linnaeus, 1758 from South-West
Adriatic Sea
Maxi Castrillejo
Cerastoderma edule as a new proxy of historical liquid releases from European nuclear reprocessing
plantsPhoebe T.W. Chan
Modern-day decline in skeletal density of subarctic crustose coralline algae
Leila Chapron
Impact of global change on cold-water coral growth: threats to deep-sea ecosystems
Ming-Tsung Chung
Plasticity of field metabolic rate between genetically distinct and coexisting cod populations
Audrey M. Darnaude
Otolith analysis and particle drift modelling to investigate variation in early life connectivity for thegilthead sea bream in the Gulf of Lions
Kristine L. DeLong
Corals are not thermometers – How to extract a geochemical time series from a complex skeleton
55th International Sclerochronology Conference, ISC 2019

Côme Denechaud
Investigating long term temporal stability of otolith morphometry of Northeast Arctic cod (Gadus
morhua) in the Barents Sea
Helene de Pontual
Asymmetry of otolith chemical composition from 2D mapping: relationship with biomineralization
mechanisms and implications for microchemistry analyses
Niels J. de WinterReconstructing paleoseasonality in the Late Cretaceous greenhouse world: A multi-proxy approach
Justine Doré
Ba/Ca as a potential proxy for phytoplankton dynamics in Arctica islandica shells from Saint-Pierre
and Miquelon (Northwest Atlantic Ocean)
Evan Edinger
Deep-water octocoral sclerochronology and microgeochemistry in cold waters of Atlantic and Arctic
CanadaPeter Fink-Jensen
Provenance and stock structure of capelin in Greenland using microchemistry
Asier García-Escárzaga
Shell sclerochronology and stable oxygen isotope ratios from the limpet Patella depressa Pennant,1777: Implications for palaeoclimate reconstruction and archaeology in northern Spain
Bronwyn M. Gillanders
Using hard structure chemistry and growth increment chronologies to investigate partial migration:
implications for fisheries management
Alejandro Román González
Developing subannual isotope records from fingernail-sized shells from Antarctic coastal waters
Marc Gosselin
Sclerochronological study in the Arabian Peninsula: growth pattern calibrations on modern bivalves
and archaeological application from shell middens
Madleen Grohganz
Unravelling the biology of conodonts (early vertebrates) through sclerochronology of their skeletal
tissues
Yvette HeimbrandSeeking the true time: Exploring otolith chemistry as an age-determination tool
Sarah Holmes
A novel study combining sclerochronology and biogeochemical modelling to understand mechanisms
controlling bivalve growth on the North West European shelf
Karin Hüssy
The “who, when and where” of cod migrations in the Kattegat
65th International Sclerochronology Conference, ISC 2019
Andrew L.A. Johnson
Growth rate, extinction and survival among late Cenozoic marine bivalves of the US eastern seaboard
Taro Komagoe
Sclerochronological and geochemical approach for paleo typhoon seasonality reconstruction using
giant clam fossils in Kikai Island, Japan
Kaoru Kubota
Geochemistry and sclerochronology of Mercenaria stimpsoni collected from the western North
Pacific
Franck Lartaud
Sclerochronology beyond the deep
Emilie Le Luherne
Can otolith δ18O of tagged fish informed about migration behaviors and population structure ofEuropean sea bass in the North East Atlantic?
Emma Loftus
Stable isotope investigations of Later Stone Age shellfishing and local climate shifts on the South
African west coast
Kelsie Long
High-resolution oxygen isotope records from fish and shell remains, Lake Kutubu, Papua New Guinea
Roger Mann
A 250 year chronology of Arctica islandica in the Mid-Atlantic region of the US continental shelf
Krešimir Markulin
Glycymeris pilosa - spatial and temporal insight into differences of trace element records
Filipe Martinho
Daily growth chronologies in a marine flatfish during estuarine colonization
Malcolm McCulloch
Reconstructing the upper-ocean 13C Suess-effect using high-resolution sclerosponge records andimplications for the oceanic CO2 sink
Christopher McQuaid
Endolithic cyanobacteria: a complication for the study of ecology and sclerochronology
Stefania Milano
Temperature-induced mineralogical transformations of aragonitic mollusc shells
Beatriz Morales-Nin
Exploring illicia microchemistry: a new tool for fish age determination?
Alexandra Németh
Anomalous 18O-depletions of Madeiran Glycymeris growth increments – A new tool to trace
meridional shifts of the Azores Front75th International Sclerochronology Conference, ISC 2019
Nicholas Farley
Evaluating Porites microatolls for climate reconstructions: Records from French Polynesia
Kozue Nishida
Microscale stable isotopic analytical system (MICAL3c) reveals high-resolution temperature history offish otoliths
Joyce Ong
Drivers of synchrony among deep-water snappers
Morgane Oudot
Biomineralization in Spirula spirula: first proteomic data and new microstructural inputs
Sierra V. Petersen
Separating seasonality in temperature and the oxygen isotopic composition of water: Sub-annual
clumped isotope analysis of gastropods
Marine Randon
Coupling individual natural tracers to assess the connectivity within a flatfish metapopulation
Patrick Reis-Santos
Influence of El Niño Southern Oscillation events on otolith growth and chemical chronologies indusky grouper
David Reynolds
Northern Hemisphere ocean atmosphere interactions over the last 500 years
Raquel Ruiz-Díaz
Hindcasting for forecasting. Disentangling the impact of environment and fishing in Flemish Cap
Atlantic cod dynamics
Jorune Sakalauskaite
The “jewel of Mediterranean” Spondylus gaederopus: insights into the biomineralization throughbiomolecular analysis
Nicolai Schleinkofer
Assessing geochemical seawater temperature proxies in the deep sea bivalve Acesta excavata
Bernd R. Schöne
Brachiopods – faithful recorders of ocean properties?
James Scourse
Atlantic herring recruitment in the North Sea for the past 455 years based on the δ13C from annual
shell increments of Arctica islandica
Kohki Sowa
Ecological responses of coral reef under different seawater conditions inferred from mid-Holocene
coral reefs at the central Ryukyu Islands, Japan
Susanne E. Tanner
How do deep-sea fish respond to environmental change: Patterns and drivers of growth variation
among space, time and taxonomy
85th International Sclerochronology Conference, ISC 2019

Elizabeth Tray
Investigating scale trace element microchemistry as a tool to track adult North Atlantic salmon
populations
Clive Trueman
Inferring movement tracks of individual baleen whales from chemical records combined with coupledsimulation models
Peter van der Sleen
Linking sclerochronology to fish population dynamics
Louise Vaughan
Relating patterns in annual growth of a Western Irish European eel Anguilla anguilla Linnaeus, 1758
population to habitat and climatic conditions
Mikko Vihtakarisclero: an R package to measure growth patterns and align sampling spots in chronologicallydeposited materials
Gotje von Leesen
Temperature association and exposure of Icelandic cod (Gadus morhua) over the last 100 years
Eric O. Walliser
Paleoseasonality in the benthic environment of the Tethys during the Late Cretaceous
Jacob Warner
Local perspectives on ENSO mean states ~2300 B.P. and now: δ¹⁸O reconstructions from the shortlived bivalves Donax obesulus and Mesodesma donacium
Tsuyoshi Watanabe
A 150 years Margritifera shell record reveals that summer air temperature in northern Japan is linked
to Atlantic Multidecadal Oscillation
Nina M. Whitney
Insights on AMOC dynamics over the last 300 years using multiple geochemical proxies from an
Arctica islandica record in the western North Atlantic
Rob Witbaard
Seasonal patterns in shell gape activity of Arctica islandica
Atsuko Yamazaki
Linkage between climate condition and coral reef development on Holocene uplifted terraces in Kikai
Island, Japan
Liqiang Zhao
Large-scale mapping of 143Nd/144Nd ratios in bivalve shells for geographical traceability
Meghan Zulian
Evidence that coralline red algae are tougher than we thought - Industrial era pH seasonality andlong-term trends in the Canadian Arctic Archipelago
95th International Sclerochronology Conference, ISC 2019

Poster presentations
Presenting authors are listed below in alphabetical order with abstract titles (pages 99-171).
Alexander Arkhipkin
Increment microstructure of the gladius in recent squid helped to assess duration of ontogenetic
phases in Jurassic belemnites (Mollusca: Cephalopoda)
Lucian Barbu-Tudoran
Unravelling native nanostructured details in high resolution scanning electron microscopy (HRSEM)
of wasted marine biomaterials
Christine N. Bassett
Examining the potential of Pacific abalone as a novel high-resolution archive of seasonal upwelling in
the Channel Islands, CA, USA
Fabian Bonitz
Climate variability of North Atlantic water masses along the Irminger Current: Insights from Arctica
islandica shells from SW Iceland
Thomas C. Brachert
Coral calcification during the geological past – why was it so different?
Valentina Brandolese
Sclerochronology and stable isotope records (δ18O) of Lower Jurassic lithiotid bivalves from theTrento Platform (Southern Alps, Italy)
Paul G. Butler
Analysis of the persistence of seasonal stratification in the northern North Sea using a δ18Oshell - based
bottom water temperature reconstruction for the last 455 years
Pierluigi Carbonara
Growth and age validation of thornback ray in the West-Central Mediterranean basin
Pierluigi Carbonara
Ring deposition patterns in common sole otoliths from the Adriatic Sea
Michael Carroll
Extended chronology of the bivalve Serripes groenlandicus from a high-Arctic fjord in Svalbard,
NorwaySimon Chenery
Mapping and quantification of sub-annual trace element variation in otoliths of toothfish(Dissostichus eleginoides) using µXRF and LA-ICP-MS
Simon Chenery
Micro-chemical and micro-mineralogical techniques for sclerochronological studies – which one
should I choose?

10

5th International Sclerochronology Conference, ISC 2019Charlotte Colvin
Determining spatial and temporal compositional variation in Buccinum undatum shells
Thierry Corrège
Deciphering high resolution structural and geochemical signals present in Stromatoporoids from theupper Cretaceous
Gaia Crippa
Bivalve shells as archives of seasonality during the early Pleistocene in the Mediterranean Sea
Jean-François Cudennec
Highlighting inter-individual variability in Patella vulgata shell growth: what consequences for paleoenvironmental proxies?
Marisa Dusseault
Structural order in biogenic carbonates: Screening for diagenesis with FTIR
Daria Ezgeta-Balić
Sclerochronology of oyster shells – differences in trace and minor element composition between
native Ostrea edulis and invasive Magallana gigas
David H. Goodwin
Bivalve mollusk sclerochronology in a changing world: Environmental controls on the growth ofMercenaria mercenaria from North Carolina, USA
Marc Gosselin
The carpet shell Ruditapes decussatus in archaeological context: insights on season of collection andcoastal paleo-temperature
Jochen Halfar
Reconstruction of Arctic Oscillation driven sea ice variability in Lancaster Sound, Canadian Arctic,
using the long-lived coralline alga Clathromorphum compactum
Ian HallAnnually resolved NE Atlantic Ocean variability through the 8.2K cold event
Carmen Hernández
Age estimation and corroboration of four-spot megrim (Lepidorhombus boscii) on the Porcupine
Bank (west of Ireland)
Carmen Hernández
Northeast Atlantic chub mackerel (Scomber colias): growth pattern and age validation in Northern
Iberian waters
Nils Höche
Automation of bivalve microstructure analysis: Making a new proxy feasible
Sarah Holmes
Using anually-resolved bivalve records and biogeochemical models to understand and predict climate
impacts in coastal oceans

115th International Sclerochronology Conference, ISC 2019
Stefan Huck
Extracting seasonality signals from Late Albian bivalve shells: A multiproxy multispecies approach
Eleanor H. John
Recent ENSO Evidence from Fiji: Climate Archives in Middens (REEFCLAM)
Andrew L.A. Johnson
Microgrowth-increment and isotopic data from sub-thermocline Aequipecten opercularis:
recognition of setting and fidelity of temperature records
Brian P. Kennedy
Understanding growth variation and life history diversity in a migratory salmon population using
otolith microstructural and microchemical analysis
Daniel Killam
Giant clam growth in the Gulf of Aqaba is accelerated compared to fossil populations: The role ofnitrate aerosol fertilization
Franck Lartaud
Dramatic growth anomalies and isotopic disequilibrium characterize the shell portion of oysters
formed during the juvenile period
Matthew Long
A multi-decade record of increasing growth rates in a Mid Atlantic population of ocean quahogs
Andrea Massaro
Otolith morphometry relations of Trachurus picturatus (Bowdich, 1825) from two different areas: theCanary Islands and the Ligurian-Northern Tyrrhenian Seas
Andrea Massaro
Inferring the population dynamic from otolith phenotypes
Sanja Matić-Skoko
Fish and sclerochronology research in the Mediterranean – challengies and opportunities
Mary Elizabeth Matta
An otolith biochronology provides evidence for species interactions in the Aleutian Islands ecosystem
Madelyn Mette
Depth-dependent environmental factors control Arctica islandica shell growth variability in SW
Iceland
Guillermo Moyano
Determination of age and growth in fish of the Pacific pomfret (Brama australis) in south central andsouthern off Chile
Lizandro Muñoz
Stereoscopic vision of otoliths by microphotogrammetry
Naoko Murakami-Sugihara
The trace element composition of mussel shells reflected the tsunami-induced environmental
changes inherent in individual bays
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5th International Sclerochronology Conference, ISC 2019

Alexandra Németh
Stable isotope study of a Glycymeris glycymeris population from the Iberian Shelf
Kozue Nishida
Temperature seasonality as recorded in shell microstructure of genus Scapharca (Mollusca: Bivalvia):
new insights into the age determination and paleoenvironmental study
Kylie L. Palmer
Life history patterns of modern and fossil Mercenaria from the US Mid Atlantic Coastal Plain duringcold vs. warm climate conditions
Mirela Petrić
Age determination of the short-finned squid Illex coindetii using statolith analysis
Simona Cinta Pinzaru
Raman spectroscopy and imaging tools for correlative analyses in otoliths sclerochronology
Amy Prendergast
Mediterranean limpets and Mg/Ca ratios - using LIBS to screen for SST changes and physiologicaleffects
Amy Prendergast
Pipi shells: a new high-resolution palaeoenvironmental archive for south-eastern Australia
Lina M. Rasmusson
Exploring the potential of Arctic coralline algae as a paleosalinity proxy
Markus Reuter
Coral calcification and sclerochronology during the Middle Miocene Climate Transition
Elodie Réveillac
Do scales and otoliths tell the same shad story?
David Reynolds
An integrated carbon and oxygen isotope approach to reconstructing past environmental variability
in the northeast Atlantic Ocean
Ana Samperiz
Stylasterids: a new paleoceanographic archive?
Yuji Sano
High resolution analysis of bivalve shell by NanoSIMSJames Scourse
8.2 ka event North Sea hydrography determined by bivalve shell stable isotope geochemistry
Kotaro ShiraiMussel periostracum as a high-resolution archive of soft tissue δ15N records in coastal ecosystems
Andreja Sironić
Sclerochronology and 14C dating applied on bivalve Glycymeris pilosa from the Adriatic Sea
135th International Sclerochronology Conference, ISC 2019
Sophie Slater
Constraining palaeo-CO2 reconstructions though B isotopes in marine carbonates using the NU
Plasma II MC-ICP-MS
Szymon Smoliński
Variation of carbon isotopic composition in otoliths of Northeast Arctic cod (Gadus morhua)
Allan T. Souza
Otolith shape variations between artificially stocked and autochthonous pikeperch (Sander
lucioperca)
Maria Suciu
EDX in Bouligand pattern sclerochronology
Donna Surge
Assessing seasonality and life history of Baltic Sea Astarte borealis (Bivalvia) using oxygen isotope
ratios measured by high-precision SIMS
Kentaro Tanaka
Microscale magnesium distribution in shell of Mytilus galloprovincialis: An example of multiple
factors controlling Mg/Ca in biogenic calcite
Julien Thébault
Highly synchronous shell growth records in Laternula elliptica from Adelie Land (East Antarctica)
Elizabeth Tray
Unlocking the archive: a biochronology repository
Tamara Trofimova
Oxygen isotope composition of Arctica islandica aragonite in the context of shell architecturalorganization
Clive Trueman
Isotope chemistry of scales reveals continent-scale variation in at-sea foraging in European
populations of Atlantic salmon
Hana Uvanović
Potential for developing multispecies chronologies in the Mediterranean Sea
Mikko Vihtakari
Otolith chemistry of Greenland halibut – false hopes or an opportunity to learn about population
boundaries?
Dario Vrdoljak
Otolith geochemistry of Diplodus puntazzo and Diplodus vulgaris from marine waters and estuaries inthe eastern Adriatic Sea
Eric O. Walliser
Were inoceramid chemosymbiotic bivalves?
Alan Wanamaker
Constructing sclerochronology networks in the northwestern Atlantic: A progress report14

5th International Sclerochronology Conference, ISC 2019
Rob Witbaard
Reconstruction of bomb 14C in the North Sea derived from Arctica islandica using Laser Ablation AMS

15

Institute of Oceanography and Fisheries, Split
Photo by Mišo Pavičić

Keynote Abstracts

16

5th International Sclerochronology Conference, ISC 2019

Towards an integrated synthesis of Earth’s coupled marineterrestrial systems
Bryan A. Black1*
1

Laboratory of Tree-Ring Research, University of Arizona, USA*presenting author: bryanblack@email.arizona.edu

The pace of sclerochronological research has dramatically accelerated over the past two decades,
culminating in an increasingly global network of absolutely dated, well-replicated archives fromthe calcified structures of bivalves, fish, and corals. These records provide uninterrupted multidecadal to millennial histories of ocean climate and ecological processes that can be readily
integrated with observational physical or biological records. As such, the discipline is positioned
for unprecedented synthesis across spatial scales, trophic levels, habitats, and functional types toestablish climate-biology relationships, test hypotheses of ecosystem functioning, conduct multiproxy reconstructions, and provide constraints for numerical climate models. Combining theseannually-resolved marine records with the global network of tree-ring chronologies will enable
unprecedented synthesis of ocean-atmosphere trends and interactions at hemispheric scales. In
the coming years, these ‘present-past-future’ perspectives will provide multi-faceted, broad-scale
insights into ocean climate, its role in marine ecosystem functioning, and interactions with theatmosphere and terrestrial ecosystems.

Session: Climate and Oceans: Past, Present and Future17

5th International Sclerochronology Conference, ISC 2019

A view into the abyss; have we seen the limits ofsclerochronology?
Steven Campana1*1Life and Environmental Sciences, University of Iceland, 101 Reykjavik, Iceland*presenting author: scampana@hi.is

Sclerochronology has achieved mainstream acceptance in science, with the use of everything fromclimate chronologies based on coral banding, to the millions of fish otoliths used as the basis for
global fisheries management. Indeed, it now seems that all animals can be aged using periodic
growth increments, if given the appropriate funding and research. Or can they? There is atroubling minority of species that seem to resist all attempts at age determination, at least to areasonable level of precision. Are we now limited by our poor understanding of the processes
responsible for annual growth increment formation in organisms? In this talk, I will avoid talking
about the great successes of sclerochronology as applied to fish and fisheries, and instead focus
on its limitations and the reasons for its occasional failure. I will conclude by attempting to answer
the question: at what point does the elegance of sclerochronology need to be pushed aside infavour of ‘brutish’, but more accurate, alternate approaches?

Session: Fisheries Ecology and Management18

5th International Sclerochronology Conference, ISC 2019

Direct cellular activity drives the fabrication of someinvertebrate microstructures
Antonio Checa1*1Departamento de estratigrafía y Paleontología, Universidad de Granada, 18071 Granada, and Instituto
Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, 18100 Armilla, Spain*presenting author: acheca@ugr.es

In biomineralization, microstructures can be defined as aggregates of biocrystals with recurrent
3D arrangements and morphologies. Microstructures consist of a mineral phase associated with aminority organic phase. The resulting biocomposite possesses biomechanical properties well
above those of its individual components. Microstructures produced by invertebrates are madeby calcite and/or aragonite. They are highly diverse and well-ordered and most usually look very
different from inorganic aggregates. Molluscs are by far the group with the widest variety of
microstructures, followed by other groups like brachiopods and bryozoans. How microstructures
are fabricated by these animals is a central theme in biomineralization. A common tenet is thatthe organic phase is able to control most, if not all, aspects of microstructures. Nevertheless, inrecent years, there is increasing evidence that physical processes, such as crystalline competitionor physical self-organization processes may explain the internal arrangements of crystallites andorganic membranes. In other instances, the morphologies and/or distributions of suchcomponents cannot be the result of such physical operators. This study will focus on threedifferent microstructures: the calcitic/aragonitic columnar prismatic and the aragonitic helicalfibrous microstructures of molluscs, and the calcitic fibrous microstructure of brachiopods. In all
three instances, either the morphologies/dimensions of the organic networks, the non-crystalline
shapes of crystals or the presence of some associated nanostructures strongly suggest that thecells of the underlying mantle act in a coordinated fashion in order to detect the organic andmineral component elements and continue their secretion. Direct cellular activity on the
fabrication of such microstructures is also consistent with what is known about the mantle-shell
relationship in those invertebrate groups. This indicates that the mantles of some molluscs andbrachiopods have unsuspected sensorial and secretional sub-cellular abilities. The unveiling of
fabricational strategies of microstructures has relevance in adaptive morphology and evolution,and is crucial in biomimetics.

Session: Biomineralization

19

5th International Sclerochronology Conference, ISC 2019

Bivalve sclerochemistry: challenges and opportunities
David P. Gillikin1*
1

Geology Department, Union College, Schenectady, NY 12308, USA*presenting author: gillikid@union.edu

Since the seminal works of Epstein and co-workers in the early 1950s, bivalve shell geochemistry
has been used as proxy of environmental conditions. Bivalves live in nearly every aquatic
environment, have a global distribution, and are well represented in the Phanerozoic fossil record
making them an excellent target organism for environmental reconstruction. Early work focusedon oxygen isotopes which proved to be a faithful recorder of both water temperature and water
oxygen isotopes. Since then a multitude of studies have confirmed this in both marine andfreshwater bivalve shells – which closely match results from inorganic calcite and aragonite.
Carbon isotopes are more complex due to inputs of multiple sources of carbon including dissolved
inorganic carbon and metabolic carbon. Some bivalve species exhibit a strong ontogenic trend inδ13C values, whereas others do not. Nevertheless, while carbon isotopes are less straightforward
than oxygen isotopes, they certainly provide some level of information about the environment.
More recently, nitrogen isotopes in the organic material bound within the carbonate shell havebeen explored as a proxy of environmental nitrogen dynamics. Several papers have illustrated that
this new proxy has much promise. Shell δ 15N values can be used in a similar fashion to soft tissue
δ 15N values – but the possibility exists to obtain higher resolution data (down to weekly). Similar
to stable isotopes, elemental ratios in bivalve shells have also been explored as environmental
proxies since the 1950s – but since the start researchers noted strong vital effects. Some elemental
ratios have shown to be reliable temperature proxies in corals and foraminifera (e.g., Sr/Ca andMg/Ca), but this is not the case in bivalve shell carbonate. Other elements such as Ba/Ca or Li/Ca
ratios in bivalve shells have shown promise, but more work is needed. Nevertheless, generaltransfer functions have only been developed for oxygen isotopes despite more than 50 years of
research on bivalve shell geochemistry. While we can find new proxies to test, and new ways touse proxies – we should move away from attempting to apply proxies that have been shown not
to be reliable recorders of environmental conditions.

Session: Proxy Development: Challenges and Opportunities

20

5th International Sclerochronology Conference, ISC 2019

Elements, isotopes and banding patterns – Sclerochronogicalapproaches to the study physiological performance in fishesPeter Grønkjær1*
1

Deptment of Bioscience, Aarhus University, Ole Worms Allé 1, Dk-8000 Aarhus C, Denmark*presenting author: peter.groenkjaer@bios.au.dk

Sclerochronological studies of a wide range of organisms, including corals, molluscs and fish, havecontributed substantially to our knowledge of historical and contemporary ocean conditions andthe life history of the organisms. In fishes, otoliths have provided a wealth of knowledge on fish
growth patterns, habitat use and more recently also of trophic relationships. However, otoliths
may also be the new tool to investigate the physiology of fishes through studies of physiologicallycontrolled incorporation of elements and isotopes into the otolith aragonite. In this talk, I will
provide examples and ideas of how the combination of classic visual otolith analysis andmicrochemical analysis of elements and isotopes may yield new insights into the impact ofenvironment conditions on the physiology of the individual. Direct coupling of e.g. growthvariations to indicators of physiological performance may allow for tests of several unresolved
topics in marine and freshwater science, including current disputes of oxygen limitation in fishes.
These analyses can also be used to improve predictions of future macroecological patterns of fish
distribution and productivity under environmental change, as they may reveal behavioral,
physiological and genetic adaptation that modify the impact of ocean change. The use of otoliths
as recorders of physiological performance is still in its infancy. Exploitation of their potential will
require a major cross-disciplinary research effort encompassing long-term controlled
experiments, new ways of combining the information from data storage tags with otolith based
performance indicators and the collaboration between physiologists, chemists and fish ecologists.

Session: Growth, Bioenergetics and Ecosystems

21

5th International Sclerochronology Conference, ISC 2019

How low can you go? Seasonal resolution in 300-millionyear-old aragonite mollusks and the insights they provide
Linda C. Ivany1*, Marie Y. Jimenez1, Emily J. Judd1, Gregory Henkes2
1
2

Department of Earth Sciences, Syracuse University, Syracuse NY 13244, USA
Department of Geosciences, Stony Brook University, Stony Brook, NY 11794, USA*presenting author: lcivany@syr.edu

Seasonally resolved isotopic sclerochronological studies have become almost commonplace in the
Pleistocene and Recent, and examples in the Cenozoic are proliferating. Pushing such datasets
back farther into the rock record becomes increasingly complicated with age, as the specter ofdiagenesis looms larger and the global and regional context into which to place the data become
more progressively more unfamiliar and unconstrained. Nonetheless, careful work peering
through the glass darkly can allow for unique insights into very ancient environments and theecologies and life histories of long-extinct organisms.
We share seasonally resolved stable isotope data from Pennsylvanian mollusk shells collected in
the Appalachian Basin of tropical North America. X-ray diffraction and scanning electron
microscopy indicate an aragonite mineralogy with retention of primary microtextures, elemental
chemistry is consistent with the shells of living mollusks, and δ18O data reveal regular cyclic
variation over ontogeny, together suggesting that original shell carbonate is preserved and records
environmental conditions over the life histories of the animals. Cyclic variation allows
determination of lifespan estimates for these Paleozoic animals, the first to be reported. Myalinid
bivalves, lophospiridid gastropods, and bellerophont monoplacophorans measuring under 2 cm
exhibit at least 3 years of growth, suggesting slower growth and longer lifespans than seen in many
modern groups. Despite their inferred marine setting, oxygen isotope values are quite low,
centering around -4.6‰, and intraannual variation is much higher than expected for the tropics,
spanning up to 2.2‰. We invoke runoff of fresh water to the basin, concentrated in thesummertime and significantly depleted by Rayleigh distillation of water vapor along the adjacenthigh-elevation Central Pangaean Mountains. These data extend a documented trend toward more
depleted carbonate values eastward across the midcontinent sea, reflecting a decreasing salinity
gradient with increasing distance from Panthalassa, and highlight the problems with calculating
paleotemperatures from δ18O values of carbonates precipitated in epicontinental seas byassuming a marine seawater composition. While carbonate clumped isotope paleothermometry
is a potential solution to this seawater δ18O ‘problem’, we demonstrate that such data from thesearagonitic samples are related to burial diagenesis and not the Pennsylvanian paleoenvironment.
The bias toward samples from such settings in the Paleozoic, because continental margins are
more likely to be deformed, suggests that postulated warm regional and global temperature
histories from the Paleozoic should be treated with caution until epeiric oxygen isotope seawater
values can be better constrained.

Session: Paleoecology and Evolution

22

5th International Sclerochronology Conference, ISC 2019

Environmental biomonitoring – challenges forsclerochronologists
Karin Limburg1,2*
1

Department of Environmental and Forest Biology, State University of New York College of Environmental
Science & Forestry, Syracuse, NY, USA
2
Department of Aquatic Resources, Swedish University of Agricultural Sciences, Lysekil, Sweden*presenting author: klimburg@esf.edu

The structures discussed at this conference – the clams, corals, otoliths, bones, and so forth –possess the wonderful attribute of “time-stamped chemistry”. As observers, sclerochronologists
make careful measurements and do their best to interpret various trace elemental and isotopic
data. Because of the uptake properties of these hard structures, it is logical to propose that many
could potentially be used for long- or short-term biomonitoring. Yet as many researchers haveshown, the interplay of environmental exposure (exogenous supply) and physiological regulation(endogenous controls) may confuse and confound. In addition, I propose that many potentially
useful biomarkers may simply be undiscovered or currently inaccessible. Here I review current
examples from a range of hard, chronometric structures (principally otoliths), show the value of
combined approaches, and end with a challenge to our community to think creatively and broadly
about future applications.

Session: Environmental Biomonitoring & Entrepreneurship23

5th International Sclerochronology Conference, ISC 2019

Sclerochronology and archaeology in the Mediterranean:seasonal foraging patterns, environmental change, andhuman-environment interaction
Amy Prendergast1*
1

School of Geography, University of Melbourne, Australia*presenting author: amy.prendergast@unimelb.edu.au

Humans respond to changes in their local environment on daily to seasonal timescales. Therefore,robust assessments of the impact of environmental change on human behaviour requires anunderstanding of local environmental change at seasonal to sub-seasonal resolution.
Sclerochronology has much to add to the study of human-environment interaction as mollusc shell
growth and chemistry provide some of the few sub-seasonal resolution palaeoenvironmental
proxies in the mid to high latitudes. Obtaining these records from food-refuse archaeological
specimens enables the reconstruction of a more detailed picture of how humans responded tochanging climatic regimes in the past and also allows an assessment of shellfish foraging
seasonality. Here we present sub-monthly resolved environmental reconstructions from stable
isotope analyses of marine and terrestrial mollusc shells from the Middle to Upper Palaeolithic
archaeological sites in the Levant. These highly resolved environmental records, coupled with welldated archaeological sequences provide a framework for assessing the complex interplay between
early modern humans and their local environments. We found evidence for fluctuating
temperature, rainfall and seasonality regimes throughout marine isotope stage 3, some of whichappear to be linked to northern hemisphere millennial-scale climate oscillations. The
archaeological records show human occupation of these sites occurred during both warmer andcooler phases and during both high and low seasonality regimes, and that shellfish were foraged
during all seasons. This indicates that modern human populations were somewhat resilient to theresource uncertainty that would have accompanied these changing temperature and seasonality
regimes. These paired cultural-environmental records have enabled an examination of homininenvironment interactions during critical periods of the late Pleistocene in a region withcomparatively few high-resolution climate records.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

24Seagulls, Split, Croatia
Photo by Filip Grubišić

Oral presentation abstracts

25

5th International Sclerochronology Conference, ISC 2019

Hydrographic and climate variability at St Kilda, Scotland,since the late 19th century
Stella J. Alexandroff1,2*, James D. Scourse1, Paul G. Butler1, Martin Sayer3,
Bernd R. Schöne4, Melanie Leng5,61

Geography - College of Life and Environmental Sciences, Exeter University, TR10 9EZ Penryn, United Kingdom
School of Ocean Sciences, Bangor University, LL59 5AB Menai Bridge, United Kingdom
3
Tritonia Scientific Ltd, Dunstaffnage Marine Laboratories, Oban, Scotland
4
Department of Applied and Analytical Paleontology, Institute of Geosciences, University of Mainz, JohannJoachim-Becher-Weg 21, 55128 Mainz, Germany
5
NERC Isotopes Geosciences Facilities, British Geological Survey, Keyworth, NG12 5GG Nottingham, United
Kingdom6
School of Biosciences, Centre for Environmental Geochemistry, The University of Nottingham, Sutton Bonington
Campus, LE12 5RD Leicestershire, United Kingdom
2*presenting author: s.alexandroff@bangor.ac.uk

The main aim of this study is to construct centennial records of the hydrographic variability in thelate Holocene at St Kilda, West Scotland. St Kilda is a sampling site of high importance, as its
offshore location close to the shelf margin makes it highly valuable for palaeoceanographic
reconstructions. Being practically unaffected by freshwater input and other onshore influences,and being located just south of the North Atlantic Current (NAC), it is thought to represent the
open-ocean North Atlantic signal well. The NAC is a key component of the Atlantic Meridional
Overturning Circulation (AMOC), which is crucial to heat and moisture transport to northwest
Europe and influences global climate. Furthermore, the lack of freshwater input at St Kilda
facilitates a clear interpretation of stable isotope data at this location. Live and dead A. islandica
were collected in May 2016 at Village Bay, St Kilda, at 26 m depth. So far, a chronology spanning
the years 1888-2015 CE has been constructed. A ten-year record of sub-annual δ18Oshell for 1888–
1898 CE was obtained by microdrilling the juvenile increments of two shells. In addition to theseasonal δ18Oshell data, we present an annually resolved 127-yr δ18Oshell and δ13Cshell series basedon the shell chronology. Both growth patterns and isotope data are compared to instrumental
data and other proxy data from the eastern North Atlantic. Shell growth at St Kilda correlates
positively with the Atlantic Multidecadal Oscillation (AMO) and the regional phytocolour index,
while it correlates negatively with summer NAO (SNAO). The stable isotope data show the local
Suess effect as well as a warming trend from 1888 to 2015, and match regional instrumental andreanalysis data. The main growth season of A. islandica at this location is spring and summer, withmore than 80% of the shell being built May–July. We conclude that (1) this A. islandica chronology
reflects North Atlantic climate patterns of the last century, (2) δ18Oshell is an accurate proxy forregional sea surface temperatures at this location, and (3) temperature and δ13C trends at St Kilda
since the late 19th century coincide with trends reported for the North Atlantic.

Session: Climate and Oceans: Past, Present and Future26

5th International Sclerochronology Conference, ISC 2019

Challenges and applications of oxygen isotope analysis ofseason of capture of freshwater mollusks
C. Fred T. Andrus1*, Christine N. Bassett1, Barbara Voohies2, Joe D. Collins3,
Evan Peacock4
1

Department of Geological Sciences, University of Alabama, Tuscaloosa, Alabama, USA
Department of Anthropology, University of California Santa Barbara, Santa Barbara, California, USA
3
Department of Geosciences, Middle Tennessee State University, Murfreesboro, Tennessee, USA
4
Department of Anthropology and Middle Eastern Cultures, Mississippi State University, Starkville, Mississippi,
USA2*presenting author: fandrus@ua.edu

Season of capture has been measured using oxygen isotope profiles in mollusk shells fromarchaeological sites for nearly 50 years. The vast majority of these studies utilize estuarine andmarine taxa. Freshwater snail and mussel shells have been analyzed for season of capture to a far
lesser extent, due in part to complications that arise from poor preservation, irregular seasonalityof climate parameters, growth rate variation, shell abrasion, and related concerns. We present
data from modern and ancient North American freshwater bivalves; the river mussels Quadrula
pustulosa, Fusconaia flava, and Ptychobranchus occidentalis, and from the Central American
gastropod Pachychilus spp. to illustrate these challenges and demonstrate how resulting data canbe useful to archaeologists. These bivalve species are commonly found in archaeological sites inmuch of the Mississippi River drainage, while the snail is found in a variety of Maya sites. In bothcases, the shells were exceptionally well-preserved due to the unique properties of the sites,
namely carbonate-rich middens and protected cave deposits. Nearly all shells suffered somedegree of abrasion during growth, and required different sampling strategies to accommodate theresulting challenges in data interpretation. Seasonal oxygen isotope oscillations measured in themussel shells were primarily caused by temperature variation, and show limited evidence ofgrowth cessations, thus proved useful for season of capture determination. The oxygen isotope
profiles of the snail shells appear predominantly influenced by precipitation variation, but clear
seasonal oscillations were not evident in all shells.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

275th International Sclerochronology Conference, ISC 2019

Fact or fiction? Exploring the possibility of Neoglacial sea ice
off the coast of Unalaska
Christine N. Bassett1*, Fred T. Andrus1, Catherine F. West2, Michael Etnier3
1

University of Alabama, Tuscaloosa, Alabama, USA
Boston University, Boston, Massachusetts, USA
3
Western Washington University, Washington, USA
2*presenting author: cbassett@crimson.ua.edu

The annual cycling of sea ice expansion and retreat is an integral part of the climate system, which
subsequently affects a wide range of biota from micro- to macroscopic scales, including humanpopulations. A study published in 2007 suggested the presence of seasonal sea ice east of
Unalaska, Alaska, USA at Unimak Pass from approximately 4,700 to 2,500 years ago. There is no
historical record of sea this far south. If sea did exist here, it likely produced observable changes
in the distribution and behavior of flora and fauna in the region and may have had a profound
impact on humans living in the region. While global climate widely fluctuated during the Late
Holocene, the extent of these changes and how they manifested regionally and locally is poorly
constrained. This research is part of the Unalaska Sea Ice Project, which seeks to address
uncertainties of local climate and environmental change in Unalaska in response to global change
throughout the Middle to Late Holocene. Recent work with bivalve sclerochronology andsclerochemistry on shellfish remains from archaeological contexts has significantly contributed tounderstandings of past relationships between humans and their environments, especially whereenvironmental reconstructions can be combined with associated archaeological evidence. Here
we present data from stable isotope paleothermometry and growth increment analysis of shellfish
remains (Saxidomus gigantea) from the Margaret Bay site (UNL-048) and the Amaknak Spit site
(UNL-055). Results from this study provide key environmental information to which
zooarchaeological analyses can be compared to produce higher confidence interpretations ofhuman-environment interactions, as well as taxonomic changes in response to local climatechanges (or lack thereof) during this time.

Session: Climate and Oceans: Past, Present and Future28

5th International Sclerochronology Conference, ISC 2019

Seawater paleotemperature and paleosalinity evolution in
neritic environments of the Mediterranean margin during
the Miocene: insights from combined δ18O-Δ47 analyses ofbivalve shells
Justine Briard1,2*, Romuald Jaillet2, Emmanuelle Pucéat2, Marc de Rafélis1,
Emmanuelle Vennin2, Mathieu Daeron3, Didier Merle4
1

Géosciences Environnement Toulouse (GET), Université de Toulouse, CNRS, IRD, UPS, 14 avenue Edouard Belin
F-31400 Toulouse, France
2
Biogéosciences, UMR 6282, UBFC/CNRS, Université Bourgogne Franche-Comté, 6 boulevard Gabriel, F-21000
Dijon, France
3
Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRS UVSQ, Université Paris-Saclay,
F-91191 Gif-sur-Yvette, France
4
Muséum National d’Histoire Naturelle, UMR CRNS 7207 (CR2P-MNHN, CNRS,UPMC-Paris 6), Sorbonne
Universités, 8 rue Buffon F-75005 Paris, France*presenting author: justine.briard@get.omp.eu

A major climate evolution during the Cenozoic is the transition from the “greenhouse” conditionsof the late Early Eocene (~50 Ma) to our modern “icehouse” conditions with its much lower
CO2 levels and significant polar glaciation. This transition occurred through a series of steps,
including Oligo-Miocene cooling (Mi-events), the last mid-Miocene warming (MMCO) andterminal cooling (MMCT). The identification of these phases of the Antarctic ice-sheet instability
strongly relies on δ18O and Mg/Ca benthic foraminifera records from ODP / DSDP sites, and few
records currently exist from shallow environments. Reconstruction of shallow water temperatures(SST) in coastal environments using bivalve δ18O can be impeded by variations in local seawater
δ18Osw linked to fluctuations in local hydrological cycle. One way to circumvent this limitation is tocombine δ18O with clumped isotope (Δ47) analyses of bivalve to decipher the evolution of SST andlocal δ18Osw. We tested in this work the potential of this combined approach to reconstruct theevolution of SST and salinity over the latest Oligocene to Middle Miocene interval (~10 Ma). Two
outcrops have been selected, at Carry-le-Rouet and Castillon-Du-Gard within the Liguro-Provencal
Basin (SE of the Mediterranean Sea) that present sediments deposited in shallow open marine
environments with bivalve fauna. Our dataset provides new information on both SST and salinity
evolution within a still understudied region and as such contributes to increase our knowledge ofthe regional environmental response to global climatic changes during this key interval of
Antarctica ice-sheet instability. SSTs oscillate between 15 and 20°C for the Aquitanian with a large
estimated salinity range (18-34‰) pointing to the occurrence of sporadic freshwater inputs during
this interval. For this stage, combined δ18O and Δ47 analyses within the largest bivalve samples
provide for the first time an estimation of seasonal SST and salinity variations. Our data highlight
limited seasonal temperature variations but larger seasonal salinity variations with dry winters
and wet summers, in agreement with the palynological data in this region during the Miocene.
Burdigalian SSTs are generally warmer by ~ 5°C with higher salinities (38-39‰). The Langhiansamples display surprisingly low SSTs (15-20°C) from Δ47 data for this time interval, described as aclimatic optimum, which in combination to δ18O values lead to low calculated salinities (32-33‰).
These data may point to a local discharge of cool submarine groundwaters, that would be inagreement with the concomitant proliferation of bryozoan observed in the Castillon-Du-Gard
area.
Session: Climate and Oceans: Past, Present and Future29

5th International Sclerochronology Conference, ISC 2019

Corals reveal a cooler and fresher tropical Atlantic during the
mid-last interglacial
William M. Brocas1*, Thomas Felis1, Manfred Mudelsee2,31

MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
Climate Risk Analysis, Heckenbeck, Bad Gandersheim, Germany
3
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
2*presenting author: wbrocas@marum.de

The last interglacial (LIG, Marine Isotope Stage 5e, 127-117 ka) is widely cited to have experienced
globally warmer than modern temperatures, however the regional differences that occurred
during this time are poorly understood. This challenge must be addressed if the LIG is to continue
to offer a test-bed for quantifying natural climate variability relevant to the assessment of futureclimate change scenarios. To better constrain the natural response, variability and spatiotemporal
evolution of the climate system during a warmer climate background, tropical Atlantic sea surface
temperatures (SST) and hydroclimate reconstructions are required. We achieve this by extracting
paleoclimate records contained within the annually banded skeletal structure of Diploria strigosa
corals. These fossil corals thrived in shallow waters environments and are now preserved upon
the uplifted reef terraces of the southern Caribbean island of Bonaire (Caribbean Netherlands).
Using precise 230Th/U dating methods we present eight snapshots, from between 130 and 118 kaago, of monthly resolved coral Sr/Ca records to reconstruct tropical Atlantic mean annual SST
changes. Coral δ18O was measured on the same samples and the Sr/Ca derived SST component
removed in order to reconstruct simultaneous δ18Oseawater records, from which hydroclimatechanges are revealed.
During the early LIG, at 129 ka, we reconstruct modern-like SST and hydroclimate. This was thenfollowed by cooler than modern SST at ~125 ka, a finding that provides new independent
evidence, in support of tropical Atlantic sedimentary records, for a cooler than modern tropicalAtlantic during a period of globally warmer SST. We contribute to the paucity of LIG hydroclimate
records by also revealing that less saline surface waters accompanied cooler SST at that time.
Taken together our corals indicate an altered oceanic system that promoted the advection ofcolder and fresher waters during the mid-LIG. Our corals then reconstruct, between ~124 ka and118 ka, modern-like SST and salinities suggesting the late-LIG experienced a return to an oceanic
regime similar to modern. While the prominent insolation forcing associated with the LIG has beenpreviously shown to strongly influence the seasonality of SST and hydroclimate, our findings
suggest mean annual values were indirectly affected. We also discuss error estimations and theimportance of incorporating uncertainties related to modern inter-colony offsets and thecalibration of coral Sr/Ca and δ18O to SST. This study highlights the climate instabilities and regional
complexities that occur within the natural climate variability of interglacials periods.

Session: Climate and Oceans: Past, Present and Future30

5th International Sclerochronology Conference, ISC 2019

Reconstructing growth histories across multiple fish species
in the Celtic Sea using multidecadal otolith collections
Deirdre Brophy1*, Amanda Egan1, Yéléna Brison Bika Bika1, Deirdre Lynch2,
Cóilín Minto1
1
2

Marine and Freshwater Research Centre, Galway Mayo Institute of Technology, Galway, Ireland
Marine Institute, Renville, Oranmore, Co Galway, Ireland*presenting author: deirdre.brophy@gmit.ie

Archived fish otoliths, collected for the purposes of age-determination and stock assessment holda wealth of individual-based information collected over multi-decadal time scales.
Sclerochronological techniques can be used to reconstruct past growth histories from annual
otolith increments in order to investigate temporal trends in growth at an individual andpopulation level. Coupling this data with environmental and biological time-series can help toelucidate drivers of observed change. This study used archived collections of otoliths to investigate
multi-decadal (1980’s to 2010’s) variability in the growth of three species from the Celtic Sea:
plaice (Pleuronectes platessa L.) herring (Clupea harengus L.) and haddock (Melanogrammus
aeglefinus L.). Otoliths were imaged under a stereo-microscope and the distances between annual
growth bands (annuli) were measured across the entire growth history of each individual. Linear
mixed effects modelling was used to partition environmentally driven inter-annual growthvariability from age-related, sex-related or cohort specific trends. The resultant trends were
further analysed in relation to environmental conditions (temperature, food availability,
meteorological conditions) and abundance (recruitment, spawning stock biomass). Sources ofvariability in growth, and their relative importance, differed substantially between species. In
plaice, within cohort growth patterns were indicative of sampling effects and/or size selective
fishing (increase in proportion of faster growing fish overtime) while in haddock there wasevidence of size dependant mortality (removal of slower growing fish over time). Growth ofherring and plaice showed small scale interannual fluctuations while a strong directional increasein the growth of haddock was detected. Annual growth patterns linked primarily with bottom
temperature (plaice), mean AMO (herring) and sea surface temperature (haddock). The relative
importance of population specific and broad scale ecosystem level change in the Celtic Sea are
examined.

Session: Growth, Bioenergetics and Ecosystems

31

5th International Sclerochronology Conference, ISC 2019

Shell midden archives, climate change and human response
in Barkley Sound, British Columbia
Meghan Burchell1*, Nadine Hallmann2, Greg Monks3, Marisa Dusseault4, Bernd
R. Schöne51Department of Archaeology, Memorial University, 310 Prince Philip Drive, St. John's, NF A1C 5S7, Canada
Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, Aix-Marseille
Université, Aix-en-Provence, 13545, France
3
Department of Anthropology, University of Manitoba, 32 Fletcher Argue Building, 15 Chancellor Circle,
Winnipeg, MB R3T 2N2, Canada
4
Department of Physics and Physical Oceanography, Memorial University, St. John's, NF A1C 5S7, Canada
5Institute of Geosciences, University of Mainz, Mainz, 55128, Germany
2*presenting author: mburchell@mun.ca

Shell midden sites on Canada’s Pacific Northwest Coast provide an ideal opportunity to apply
sclerochronology (stable oxygen isotopes and growth patterns) to refine interpretations ofchanges in local sea-surface temperature and hunter-fisher-gatherer subsistence practices. In thispresentation, we examine a 3000-year shell midden archive from the west coast of Vancouver
Island to examine how, and if, two climatic anomalies, the Little Ice Age (LIA) and Medieval Warm
Period (MWP) can be detected in the archaeological record, and if local environmental changes
affected human subsistence and settlement. Zooarchaeological analysis of fish remains recoveredfrom the T’ukw’aa village site and the smaller site of Ma’acoah near mouth of Toquart River,demonstrated a shift from salmon to rockfish in assemblages dated to the LIA and MWP,
respectively. This change in fishing practices, combined with other faunal data, suggests there may
be other changes in subsistence practices, such as seasonal shellfish harvesting. To further
understand subsistence practices in relation to local environmental changes, we conductedsclerochronological analysis and stable oxygen isotope (δ18O) analysis on Saxidomus gigantea(butter clam) from two sites from the traditional territory of the Nuu-chah-nulth, specifically the
Toquaht of Barkley Sound, British Columbia. Through the analysis of monthly-collected live S.
gigantea and archaeological specimens, we also evaluate the effects of sampling between modern
and fossil assemblages. We integrate new δ18Oshell data with direct radiocarbon dates to improvesite chronologies, and demonstrate how bivalve shells can be used to refine interpretations ofhuman-response to environmental change from ancient and historic shell midden assemblages.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

325th International Sclerochronology Conference, ISC 2019

An ecological perspective of age and growth in Mullus
surmuletus Linnaeus, 1758 from South-West Adriatic Sea
Pierluigi Carbonara1*, Loredana Casciaro1, Alessandro Cicolella2, Francesco De
Franco2, Marilena Donnaloia1, Giuseppe Lembo1, Maria Teresa Spedicato1,
Walter Zupa1, Paolo Guidetti3
1

COISPA Tecnologia & Ricerca, Stazione Sperimentale per lo Studio delle Risorse del Mare, Via dei Trulli 18/20
70126 Torre a Mare (BA), Italy
2
Consorzio di Gestione di Torre Guaceto Via Sant'Anna 6 - 72012 Carovigno (BR), Italy
3
Université Nice Sophia Antipolis Parc Valrose 28, avenue Valrose 06108 Nice Cedex 2, France*presenting author: carbonara@coispa.it

The growth rate is a peculiar trait of the life history for each species. The amount of energy
allocated to growth and the other physiological activities (e.g. reproduction, predation, migrationetc.) depends on a number of factors, some of them are intrinsic (e.g. genetic and physiological),other are environmentally driven (e.g. temperature, food availability). Thus, a compromise onenergy balancing must exist reflecting the specific growth and other physiological activities in thelife of an individual fish. Moreover, fisheries remove individuals at various trophic levels in theecosystem, affecting the distribution of energy and hence the amount of energy available. In thisway, fishery activities influence fish growth and maturation dynamics. This might also explain thehigh growth variability among populations of several species, despite their relatively high genetic
homogeneity and/or nearness. Growth, therefore, characterizes the species from a biologicalpoint of view (trait of life history), but also it has an ecological implication because in turn it isinfluenced by the environment in terms of energetic flow.
The objective of this study is to compare the growth of a costal species, the stripped red mullet(Mullus surmuletus), under two levels of anthropogenic pressure (fishing) in South Adriatic Sea(Central Mediterranean). The two study locations are the Marine Protected Area (MPA) of Torre
Guaceto and the unprotected coast around Monopoli (South-West Adriatic Sea). These two
locations are about 60 km away from each other and have similar bottom/biocenosis
characteristics. M. surmuletus is an important target species mostly for the small-scale fishery inboth locations.
For the purpose of this study, the otoliths of 50 female specimens were collected in each area andanalysed. Then a transparent rings back-calculation was performed. The specimens in the two
locations were selected with the same frequency of transparent rings number in order to avoid
any sampling bias. Through the back-calculation the growth curves of M. surmuletus were
estimated in each study location. The two curves were significantly different, mostly from the age
2 onward and M. surmuletus specimens from the MPA displayed a higher growth rate. These
results suggest that, from an ecological perspective, intraspecific (e.g. density) and interspecific(e.g. energy flow through the food web) relationships could change depending on the level ofprotection against fishing exploitation.

Session: Fisheries Ecology and Management33

5th International Sclerochronology Conference, ISC 2019

Cerastoderma edule as a new proxy of historical liquid
releases from European nuclear reprocessing plants
Maxi Castrillejo1*, Marcus Christl1, Rob Witbaard2, Rob Dekker2, Christopher A.
Richardson3, Jose-Luis Mas Malbuena4, Núria Casacuberta1, Christiane Yeman1,
Lukas Wacker1, Caroline Welte1,5, Hans-Arno Synal1
1

Laboratory of Ion Beam Physics, ETH - Zurich, Switzerland
NIOZ Royal Netherlands Institute for Sea Research and Utrecht University, The Netherlands
3
School of Ocean Sciences, Bangor University, United Kingdom
4Departamento de Física Aplicada I, Universidad de Sevilla, Spain
5
Biogeosciences, ETH - Zurich, Switzerland
2*presenting author: maxic@phys.ethz.ch

Nuclear reprocessing plants of La Hague (France) and Sellafield (England) have been legallydischarging liquid radioactive waste to the sea for more than 5 decades. As a consequence, theseawater flowing through the English Channel and the Irish Sea is labelled with several artificial
radionuclides that can be used to investigate the downstream transport of water into the Arctic
and North Atlantic oceans. One of these radionuclides is the long-lived 236U (T1/2=23.4 Ma), which
recently has been made available to the oceanographic community as a tracer of water circulation.
So far, the 236U tracer cannot be fully exploited because of a substantial gap of knowledge on its
release history from Sellafield and La Hague. Therefore, the main goal of this study is to create thevery first observational-based reconstruction of historical 236U releases from La Hague using
Cerastoderma edule as a recorder of sea water 236U/238U levels. So far, we measured the uranium
content in the shells of 2-year-old C. edule collected alive every 1-2 years as part of a long term
(1960-present) fauna sampling program in Balgzand (main inlet to Wadden Sea, Netherlands). The
archived shell material is ideal because the location is under the direct influence of the coastal
water carrying the isotopic signature of La Hague discharges, and the time coverage of theavailable shells represents the period of documented main 236U discharges from the nuclear
facility (1966 to present). Preliminary results show that the contemporary shell material
consistently records the 236U/238U atom ratios in overlying seawater and that there is no significant
exchange with the surrounding sediments. Furthermore, the shell-based reconstruction of past
236
U/238U atom ratios compares well to modelled uranium ratios in the coastal water on basis of
documented 236U discharges. The time series of 236U/238U measured in the shells agrees with themodel output for most of the 236U release period suggesting that C. edule is a suitable candidate
for reconstructing past uranium levels in seawater. This study is being extended to reconstruct therelease of 14C and 129I circulation tracers from La Hague and Sellafield reprocessing plants.

Session: Environmental Biomonitoring & Entrepreneurship34

5th International Sclerochronology Conference, ISC 2019

Modern-day decline in skeletal density of subarctic crustosecoralline algae
Phoebe T.W. Chan1*, Jochen Halfar2, Christopher J.D. Norley3, Steven I.
Pollman3, David W. Holdsworth3, Walter H. Adey4, Phillip A. Lebednik5, Douglas
Rasher6, Robert Steneck7
1

University of Bergen & Bjerknes Centre for Climate Research, Jahnebakken 5, Bergen 5007, Norway
University of Toronto, 3359 Mississauga Rd. North, Mississauga, Ontario L5L 1C6, Canada
3
University of Western Ontario, 1151 Richmond St. North, London, Ontario N6A 5B7, Canada
4
Smithsonian National Museum of Natural History, 1000 Constitution Ave. NW, Washington D.C. 20560, USA
5
Lebcon Environmental Services, 3043 Naranja Drive, Walnut Creek, California, 94598, USA
6
Bigelow Laboratory for Ocean Sciences, 60 Bigelow Dr., East Boothbay, ME 04544, USA
7
University of Maine, Darling Marine Center, 194 Clarks Cove Rd., Walpole, ME 04573, USA
2*presenting author: phoebe.chan@uib.no

Warming surface ocean temperatures combined with the continued invasion of atmospheric CO2
into seawater are increasing physiological stresses on calcareous marine organisms. Ocean
acidification has been shown to have detrimental impacts on marine carbonate organisms intropical and temperate localities. However, greater oceanic CO2 uptake in high latitudes suggeststhat calcareous organisms residing in the Arctic and Subarctic are even more susceptible toacidifying conditions than those in lower latitudes. This is especially true for Clathromorphum sp.
crustose coralline algae, a dominant calcifier in Arctic/Subarctic hard-bottom communities thatbuild their skeletons using high Mg-calcite, which is even more soluble than aragonite in corals.
Here we present an annually-resolved skeletal density record from crustose coralline algacollected from the Aleutian Islands in the subarctic North Pacific, a region that has undergone
significant environmental changes over the last century.
Coralline algal skeletal densities were determined using micro-computed tomography (micro-CT)
as described in Chan et al., (2017). Results show that shallow-collected (8-10 m) and deepcollected (25 m) specimens exhibit very different trends in skeletal density, with shallow samples
exhibiting a more gradual decline, whereas in deep samples, density increased before decreasing
sharply near the end of the record. This decline in modern-collected specimens (in 2008 and 2014)
is not evident in museum specimens (collected in 1969), which suggests that the decline is not an
artifact of a slowdown of growth rates over time. In addition to declining pH in the Aleutian region,
diminishing algal density may also be associated to temperature stress resulting from increasing
sea surface temperatures (SST) recorded in the region. This is demonstrated by a significant
negative relationship between algal density and the Hadley Centre Sea Ice and Sea Surface
Temperature (HadISST) data set - such that increasing (decreasing) algal skeletal density is
associated with cooler (warmer) SST.
The ecological benefits of sustained vertical growth and calcification in coralline algae may allow
organisms to quickly heal and regenerate skeletal/thallus mass from damaging disturbance events
such as wave action and herbivore grazing, both of which are common features of the AleutianIsland nearshore ecosystem. However, the metabolic tradeoffs associated with weakening algal
skeletons may offset the benefits of continued growth and calcification, and expose skeletons
to both physical and biological erosional processes, with anticipated consequences for the diverse
reef-like communities associated with algal structures.

Session: Climate and Oceans: Past, Present and Future35

5th International Sclerochronology Conference, ISC 2019

Impact of global change on cold-water coral growth: threats
to deep-sea ecosystems
Leila Chapron1*, Erwan Peru1, Alexandra Engler1, Pierre Galand1, Franck
Lartaud1
1

Sorbonne Université, CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques, LECOB, F-66650,
Banyuls-sur-Mer, France*presenting author: leila.chapron@obs-banyuls.fr

Skeletal growth is a key physiological function, which in the case of calcifying organisms, provides
structure and protection for internal soft tissues. Additionally, the skeleton of engineer species
such as scleractinian corals, form three dimensional structures that support the local biodiversity.
Questions regarding how the environment impacts the growth of calcifying pieces are thus ofparamount importance for various ecosystems, particularly in a changing ocean. This is typicallythe case for cold-water corals (CWC) reefs and their key ecological functions in the deep-sea. But
shortly after their discovery, it has been demonstrated that CWCs are facing several serious
anthropogenic threats, including deep-sea fishing, waste discharges, global ocean warming andacidification.
Plastic contamination, such as macro- and microplastics debris which accumulate in surface anddeep waters, is now recognized as one of the most serious environmental issues for oceans. Also,
the warming of deep marine waters as a result of climate change is known to affect physiological
functions, such as skeletal growth. This danger has become all the more relevant considering that(1) scleractinian CWCs live at the uppermost of their thermal tolerance range in the Mediterranean
Sea and (2) Mediterranean submarine canyons are highly contaminated by plastic wastes. Thus,
the aim of our study was to investigate whether plastics and temperature could affect growth ofthe main deep engineer specie, Lophelia pertusa.
Based on experimental aquarium approaches, the coral growth rates were measured using achemical marker, calcein, that is incorporated into the skeleton. Our studies show, in one hand,that growth rates of L. pertusa are affected by both macro- and microplastics debris, likely related
to a barrier effect for macroplastics and energy costs during ingestion and/or egestion processes
for microplastics. On the other hand, skeletal growth changes with temperature, leading tomaximum growth rates at 13°C (i.e., the present temperature in the habitat) and a significant
decrease at 15°C (i.e., expected temperature by the end of the century). Considering the highaccumulation of plastic debris on the seafloor and the ongoing global climate change, our results
suggest that these combined stressors constitute major threats for reef aggradation, and thus
jeopardise the resilience of cold-water coral reefs and their associated biodiversity.

Session: Growth, Bioenergetics and Ecosystems

36

5th International Sclerochronology Conference, ISC 2019

Plasticity of field metabolic rate between genetically distinct
and coexisting cod populations
Ming-Tsung Chung1*, Kris-Emil Mose Jørgensen1, Clive N. Trueman2, Rasmus
Hedeholm3, Sara Bonanomi4, Einar E. Nielsen5, Thomas Brændgaard1, Peter
Grønkjær1
1

Department of Bioscience, Aarhus University, Denmark
Ocean and Earth Science, University of Southampton, UK
3
Department of Fish and Shellfish, Greenland Institute of Natural Resources, Greenland
4
Institute of Marine Sciences, Italian National Research Council, Italy
5
National Institute of Aquatic Resources, DTU Aqua, Denmark2*presenting author: mingtsungchung@bios.au.dk

Metabolic rate is a fundamental property setting daily energy requirements for individuals, andknowledge of metabolic costs associated with maintenance, foraging, growth and reproduction
under natural conditions is important for understanding the energetic consequences ofenvironmental change at population, community and ecosystem levels. If we want to understandhow animals perform in the wild and operate within a complex environment, time-integrated
individual-level field metabolic rate is the ecologically and evolutionarily relevant trait to study,
and it can be investigated through natural stable carbon isotope tracers in otoliths. Isotopic
composition of carbon in otolith aragonite can be used as a proxy field-based for oxygen
consumption rates in Atlantic cod (Gadus morhua), as the otolith δ13C value is a weighted averageof the δ13C values of water and metabolic carbon. We describe the mechanistic relationshipbetween otolith inorganic δ13C values and oxygen consumption under laboratory conditions anduse this proxy to evaluate spatial, temporal and genetic influences on metabolic performance ofAtlantic cod in natural habitats. The otolith metabolic proxy provides evidences to support existing
ecological assumptions or hypotheses. (1) The metabolic rate of fish varies among individuals thatis linked to phenotypic plasticity and is expressed in the life history and personalities. (2) Fish livingin the cold water respond to an environmental temperature increase by reducing metabolic rates
and energy costs. (3) Selective pressure from fishing activity not only changes the population size
but also shapes the population metabolism. Current theory predicting the performance of fishunder different climate change scenarios and environments, typically does not take into accountindividual behavioural and physiological responses and adaptation, or altered metabolic costs
associated with changing foraging and predation dynamics. Otolith-based measurements ofindividual-level field metabolic rates could provide data needed to enhance ecological models andcould provide more accurate and precise predictions of fish population dynamics, behaviour andadaptation under a long-term environmental change.

Session: Growth, Bioenergetics and Ecosystems

37

5th International Sclerochronology Conference, ISC 2019

Otolith analysis and particle drift modelling to investigate
variation in early life connectivity for the gilthead sea breamin the Gulf of Lions
Audrey M. Darnaude1*, Maylis Labonne1, Christophe Lett2, Chloé Vagnon1,
Cécile Petit1, Sophie Hermet1, Sadjia Belkacemi112MARBEC (CNRS, Univ. Montpellier, Ifremer, IRD), Montpellier, France
IRD (UMI 209 UMMISCO), Sète, France*presenting author: audrey.darnaude@cnrs.fr

Effective management of fish resources requires a good knowledge of the local connectivity
patterns responsible for the genetic structure of the exploited stocks, especially for species with alife cycle that involves migration at varied life stages. Yet, this information is still lacking for manytarget species and parts of the world. In the Gulf of Lions (NW Mediterranean) for example, little
is known about the offshore spawning sites of the gilthead sea bream (Sparus aurata) or the originof the post-larvae that colonize the varied lagoon used as nursery sites by the species. In this work,
we investigated the number and location of these spawning grounds and their respective
contribution to the juvenile sub-populations of four varied lagoons (Mauguio, Thau, Salses andBages) recognized as the main local nursery sites for S. aurata. For this, we used both the left andthe right otoliths (sagittae) of >200 early juveniles from three different cohorts. Right otoliths wereused to evaluate the variability in hatching dates among lagoon sites and years. We then modeled
potential larval drift at sea for all years and hatching dates, using two discrete zones in the Gulf ofLions where adults are known to aggregate during the winter as presumed spawning sources. The
possible migration routes obtained were then matched with concomitant environmental data
(temperature, salinity, Chl a) for the entire area, and compared with the environmental (ratios in
B, Ba, Ce, Cr, Mg, Mn, Pb, Sr, Zn and Y) and physiological (daily growth rates) information stored
in the left otoliths of the fish during the first 60 days of larval life. This allowed identifying fish
origin for all years and nursery sites and characterizing the differences in larval life history among
them. The results suggest that the sea bream juveniles of the four lagoons originate from both
spawning areas, with different larval migration routes from both sites according to fish spawning
date. These temporal differences explain differences in spawning origin among lagoons and years,
bringing new insights on the early life connectivity of Sparus aurata and its consequences for
population structure and stock maintenance in this area.

Session: Fisheries Ecology and Management38

5th International Sclerochronology Conference, ISC 2019

Corals are not thermometers – How to extract a geochemical
time series from a complex skeleton
Kristine L. DeLong1,2*, Gilman Ouellette1, Jacob Warner1, Deborah Loke1,
Marissa Vara1
1
2

Louisiana State University, Louisiana, USA
Coastal Studies Institute, Louisiana State University, Louisiana, USA*presenting author: kdelong@lsu.edu

For the past ~30 years, the geochemical variations in coral skeletons have provided many multicentury long reconstructions of temperature, salinity, and other environmental variables. As thisfield matures, there are discussions that some coral proxies are not as reliable, reproducible,
and/or difficult to interpret. Geochemical methods have improved with advances in technology
but the methods used to extract samples from the coral skeleton include hand-held rotary tools,
drill presses, and advanced computer-aided micro-milling systems. Furthermore, the methods
used for time assignment to coral samples has not improved. Our work reveals that sampling andtime assignment can have a large impact on coral proxy calibration and the resultant
reconstruction. Slabs removed from a coral core must transect the extending corallite walls so theuser can extract samples along a continuous growth-time skeletal feature. Computer-aided micromills are preferred for sampling to control the sample location and penetration depth into thecoral skeleton, which is needed to avoid non-target skeletal elements, especially for corals withlarger polyps (e.g., Siderastrea, Orbicella, Diploria, and Diploastrea spp.). Micro-mills allow for
sampling increments to be smaller than the diameter of the bit since movement can be lateral
whereas the up-down drilling sets increment size to bit diameter. For complex coral skeletons,
laser ablation can be used to extract ~weekly samples from coral skeletons but require the coral
to be cut into 1–2 cm pieces; however, advances in laser ablation large chamber technology will
help resolve this issue. Time assignment is difficult, particularly for weekly laser ablation records,
where users assigned years by-hand with guidance from x-radiographs to establish each year
and/or use QAnalyseries software (https://sites.google.com/site/geokotov/software) to assign
years and months. We find the number of “tie points” used per year changes calibration slopes.
Our recent study with gridded and interpolated SST (HadISST and ERSST) reveals non-systematic
biases at the single grid level that can significantly change calibration slopes. We recommend using
in situ SST or satellite-derived SST (AVHRR SST) for a single location. We find that the Atlantic coral,
Siderastrea siderea, has the ~same Sr/Ca-SST calibration equation for 44 coral colonies at different
sites in the Gulf of Mexico and Tropical Atlantic when using these improved sampling andcalibrating methods.

Session: Proxy Development: Challenges and Opportunities

39

5th International Sclerochronology Conference, ISC 2019

Investigating long term temporal stability of otolithmorphometry of Northeast Arctic cod (Gadus morhua) in the
Barents Sea
Côme Denechaud1,2*, Szymon Smolinski2, Jane A. Godiksen2, Audrey J. Geffen1,2
1
2

Department of Biology, University of Bergen, Norway
Institute of Marine Research, Bergen, Norway*presenting author: come.denechaud@hi.no

Otolith shape analysis provides a robust tool for the stock discrimination of many fish species,
often substituting to more time and resource-heavy methods. Separating these populations isuseful in improving fisheries management because fishing may affect different stock components
disproportionately. However, differences in otolith morphometry are caused by a complex arrayof genetic and environmental factors, making it difficult to develop a consensus on theirinterpretation. While stock discrimination using otolith shape is increasingly seen as a useful tool,
the reasons for shape variations are rarely understood. Notably, there has been little research to
examine the within-stock stability of otolith morphometry over long periods of times, in relation
to large changes in the environment and fish condition. In this study, we aim to investigate thepotential changes in the shape of Northeast Arctic cod otoliths during the period 1932-2015 andits main drivers. Otoliths contours descriptors will be extracted from archived material of maturefish of similar age classes. These descriptors will then be related to several exploratory factors
trying to explain this variability. We expect this study to not only give new insights on the stabilityof shape over time, but to also draw new conclusions regarding the importance of environmental
factors on otolith morphometry and its reliability as a stock discriminant.

Session: Fisheries Ecology and Management40

5th International Sclerochronology Conference, ISC 2019

Asymmetry of otolith chemical composition from 2D
mapping: relationship with biomineralization mechanisms
and implications for microchemistry analyses
Helene de Pontual1*, Helene Tabouret2, Kelig Mahé3, Emilie Le Luherne1,4,Françoise Daverat4, Christophe Pecheyran2
1

IFREMER Centre de Bretagne, Plouzané, France
UMR 5254, Université de Pau et des Pays de l’Adour-CNRS, Pau, France
3
IFREMER, Boulogne-sur-Mer, France
4
IRSTEA Bordeaux, Cestas, France
2*presenting author: helene.de.pontual@ifremer.fr

Although otoliths are widely used as archive to infer life history traits and habitat use in fishes,
their biomineralization process remains poorly understood. This lack of knowledge is problematic
as it can lead to misinterpreting the different types of signals (e.g. optical or chemical) that provide
basic data useful for research in fish ecology, fisheries management and conservation. Otolith
calcification relies on a complex system involving a pericrystalline fluid, the endolymph. Its
composition has been shown to be heterogeneous for some organic and inorganic constituents.
This property stems from the particular structure of the calcifying saccular epithelium. In thisstudy, we explored the heterogeneity of elemental incorporation in otoliths of two species withhigh economical interest, European hake (Merluccius merluccius) and European sea bass
(Dicentrarchus labrax). Two-dimensional mappings of chemical elements were obtained by UVfsLA-HR-ICPMS analyses on transverse sections of sagittae. Results highlighted a clear proximodistal asymmetry for some elements such as magnesium Mg, phosphorus P, manganese Mn andpotassium K with concentration gradient directions that varied depending on the analyzed
element. Chemical imaging revealed that elements such as strontium Sr, barium Ba and rubidium
Rb were symmetrically distributed between proximal (sulcus) and distal (antisulcus) sides of theotolith. These results are discussed in the light of current knowledge on endolymph composition(organic and inorganic) and mechanisms that drive its compartmentalization, resulting inasymmetrical incorporation of some of the chemical elements that cross the saccular epithelium.
In addition, these findings highlight the need 1) for further research on otolith biomineralization
mechanisms, 2) for rigorous sampling schemes in order to avoid analytical biases when using
otolith chemical signatures as proxies of fish life traits or environmental parameters, and 3) for
thorough analyses of analytical setting before comparing otolith signatures between species orgeographical areas.

Session: Biomineralization

41

5th International Sclerochronology Conference, ISC 2019

Reconstructing paleoseasonality in the Late Cretaceous
greenhouse world: A multi-proxy approach
Niels J. de Winter1*, Clemens V. Ullmann2, Anne M. Sørensen3, Nicolas
Thibault3, Martin Ziegler4, Steven Goderis1,5, Stijn Van Malderen5, Frank
Vanhaecke5, Philippe Claeys1
1

AMGC research group, Vrije Universiteit Brussel, Brussels, Belgium
Camborne School of Mines and Environment and Sustainability Institute, University of Exeter, UK
3
Faculty of Science, IGN, University of Copenhagen, Denmark
4
Stratigraphy and Paleontology group, Faculty of Geosciences, Utrecht University, The Netherlands
5
A&MS research group, Department of Chemistry, Ghent University, Belgium
2*presenting author: niels.de.winter@vub.beStudies of past climate change provide modelers with data required to calibrate models for climate
forecasting and yield valuable insights into greenhouse climates(1). The Late Cretaceous wascharacterized by much warmer global temperatures and reduced land ice volumes compared tothe present(2), and therefore serves as an interesting analogue for future climate. While long-termclimate trends in this period are frequently studied, studies of short-term (seasonal to decadal)
climate dynamics are rare, especially in higher latitudes. This study adds vital information abouttemperature seasonality in the Campanian (Late Cretaceous) age from excellently preserved
oyster (Rastellum diluvianum and Acurostrea incurva) and radiolithid rudist bivalves from thecoastal Kristianstad Basin in southern Sweden (50°N paleolatitude).
Our work combines records of a range of proxies (e.g. stable isotope, clumped isotope and traceelement ratios) from the shells of these bivalves. This multi-proxy, multi-species approach allows
us to disentangle the effects of temperature, water composition and physiology which often
complicate seasonality reconstructions in bivalves. It also provides independent control on theinterpretations made from multi-proxy records(3), and allows us to extend the nearest living
relative approach to study the expression of climate proxies in rudist shells, which are very
common in the Cretaceous(4).
The excellent shell preservation in the Kristianstad Basin makes it possible to apply conventional
oxygen isotope analysis together with clumped isotope analysis to reconstruct both watertemperature and salinity. As one of the first applications of clumped isotope thermometry in fossil
bivalve shells, this study tests the method for reconstructing absolute surface water temperatureseasonality in Late Cretaceous oceans. The combination of these methods yields a seasonaltemperature range of 22-26°C for Campanian high-latitudes with low seasonal variability inseawater oxygen isotope composition (±0.3‰) even in this coastal setting.
Finally, a detailed comparison between trace element and stable isotope proxies provides insightin the application of controversial trace element ratios for climate reconstructions. Given the highspatial resolution that can be reached using modern techniques for in situ trace element analyses(e.g. LA-ICP-MS and µXRF), the use of these proxies could bring about a significant increase in the
resolution of sub-annual climate records from bivalve shells.
1
IPCC, Climate change 2013: the physical science basis, Cambridge University Press, New York,
USA; 2Thibault, N. et al., 2016, Climate of the Past 12:2, 429-438; 3de Winter, N.J. et al., 2017,
Palaeo3 485, 740-760; 4Skelton, P.W., 2013, Caribbean Journal of Earth Science, 45:9, 33.

Session: Paleoecology and Evolution42

5th International Sclerochronology Conference, ISC 2019

Ba/Ca as a potential proxy for phytoplankton dynamics in
Arctica islandica shells from Saint-Pierre and Miquelon(Northwest Atlantic Ocean)Justine Doré1*, JulienThébault1, Pierre Poitevin1, Laurent Chauvaud1, PhilippeArchambault2, André Poirier3, Simon Bélanger4, Virginie Roy5, Gwenaëlle
Chaillou6
1

Université de Brest, Institut Universitaire Européen de la Mer, Laboratoire des sciences de l’environnement
marin (UMR6539 CNRS/IRD/UBO), Plouzané, France
2
Département de Biologie, Québec-Océan, Takuvik, Université Laval, Québec-Océan, QC G1V 0A6, Canada
3
Centre de recherche en géochimie et géodynamique (Geotop), Département des sciences de la terre et del’atmosphère, Université du Québec à Montréal, Succursale Centre-ville, Montreal, QC H3C 3P8, Canada
4
Département de biologie, Chimie et géographie, groupe BORÉAS et Québec-Océan, Université du Québec à
Rimouski, Québec G5L 3A1, Canada
5
Département des sciences benthiques, Institut Maurice-Lamontagne, Pêches et Océans Canada, Québec G5H
3Z4, Canada
6
Institut des Sciences de la Mer, Université du Québec à Rimouski, Rimouski, Québec G5L 2Z9, Canada*presenting author: justine.dore@univ-brest.fr

Global change is affecting oceans and particularly phytoplankton dynamics in coastal areas,
modifying the species composition of microalgae communities, the level of primary production
and the global biogeochemical carbon cycle. It is therefore crucial to get insights about past andpresent spatial and temporal dynamics of phytoplankton blooms. However, no relevant
geochemical, high resolution, proxies for these ecological processes have yet been found in marine
biogenic archives.
The temporal variations of barium-to-calcium ratio in bivalve shells (Ba/Cashell) are not yet fully
understood but there is a consensus among the scientific community about the fact that they are
primarily induced by the environment. Some studies went further and suggested a relationshipbetween phytoplankton dynamics and the incorporation of barium in these shells.
In order to test this assumption, Ba/Cashell was measured by LA-ICP-MS along the hinge plateof Arctica islandica (Ocean Quahog) specimens collected alive at a depth of 14 meters around
Saint-Pierre and Miquelon islands in the Gulf of St. Lawrence (Northwest Atlantic Ocean). The
Ba/Cashell time-series covers the period 2006-2018, and shows flat background levels interrupted
by erratic sharp peaks. The date of each of these peaks was identified to the nearest year using
growth increment analysis. In parallel, estimates of sea surface chlorophyll concentration were
calculated from remote-sensing data collected around these islands by SeaWIFS and Aqua MODIS
sensors.
The comparison of these two time-series let us assess the potential of this geochemical ratio as apaleo-environmental proxy for the phytoplankton dynamics in the Northwest Atlantic Ocean.

Session: Environmental Biomonitoring & Entrepreneurship43

5th International Sclerochronology Conference, ISC 2019

Deep-water octocoral sclerochronology andmicrogeochemistry in cold waters of Atlantic and Arctic
CanadaEvan Edinger1,2,3*, Sam Davin4, Bárbara de Moura Neves2,5, Krista Greeley6,
Claude Hillaire-Marcel4, Graham D. Layne3, Owen Sherwood7, Vonda WarehamHayes5
1

Geography Department, Memorial University, St. John’s, Canada
Biology Department, Memorial University, St. John’s, Canada
3
Earth Sciences Department, Memorial Universit, St. John’s, Canada
4
GEOTOP, Université de Québec à Montréal, Montréal, Canada
5
Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, St. John’s, Canada
6
Environmental Science Program, Memorial University, St. John’s, Canada
7
Earth Sciences Department, Dalhousie University, Halifax, Canada
2*presenting author: eedinger@mun.ca

Many species of deep-sea octocorals, including members of both ‘gorgonians’ (Alcyonacea) andthe ‘sea pens’ (Pennatulacea) produce mineralized skeletons, and can record oceanographic
conditions in their skeletons. Gorgonians, especially Primnoidae and Isididae, build composite
skeletons of protein and magnesian calcite, potentially recording surface and ambient conditions,
respectively. The most common gorgonian species in the NW Atlantic can live hundreds of years.
Differences in bomb radiocarbon between the protein and calcite portions of their skeletons
record deep water radiocarbon ventilation. Stable isotopes of C and N in the proteinaceous
portions of their skeletons record variations in currents and nutrient dynamics, transferred to thecorals via phytodetritus in their diets. Mg/Ca ratios in gorgonian calcites appear to record seawatertemperature. Although the corals form annual growth rings, the gorgonian calcites reflectseawater temperature variation at a decadal scale more reliably than at an annual scale. Bulk 𝛿15N
measurements of the organic portions and Pb/Ca ratios in the calcite portions of Keratoisis
skeletons from the SW Grand Banks slope, Newfoundland record Labrador current strength, andanthropogenic lead contamination, respectively. Positive correlations between skeletal Ba/Ca
ratios and 𝛿13C measurements support the use of skeletal Ba concentrations in Keratoisis as aproxy for productivity. Keratoisis from SE Baffin Bay, growing in Irminger current waters at about
1˚C apparently display much slower growth rates than their Newfoundland congeners in 4˚CLabrador slope water.
Northwest Atlantic sea pen skeletons are composed of 70-85% magnesian calcite and 15-30%
protein. Proteins appear to be distributed within the skeleton, rather than found in discrete layers.
Sea pen growth is recorded in annual growth rings, which may form by seasonal variations inprotein vs. magnesian calcite content. Sea pen growth rates are much faster in the shorter-lived
boreal species and Halipteris finmarchica and Pennatula spp. than in the Arctic sea pen Umbellula
encrinus, which can live more than 65 years. Despite their shorter lifespan than gorgonians, sea
pen skeletons may be useful in paleoceanographic reconstructions due to their broad
distributions, especially in regions without gorgonians or other long-lived skeletal archives.
Reliable correlation of height to age in sea pens allows estimation of age-frequency distributions
in sea pens based on by-catch collections and video analysis. Both gorgonians and sea pens in the
NW Atlantic and Arctic Canada provide important long-lived physical structure in deep-sea
ecosystems that contribute importantly to local biodiversity.

Session: Climate and Oceans: Past, Present and Future44

5th International Sclerochronology Conference, ISC 2019

Provenance and stock structure of capelin in Greenlandusing microchemistryPeter Fink-Jensen1,2*, Karin Hüssy1, Teunis Jansen1,2, Tonny Bernt Thomsen3,
Simon Hansen Serre3
1

Technical University of Denmark, Institute of Aquatic Resources, Kemitorvet building 201, 2800 Kgs. Lyngby,
Denmark
2
Greenland Institute of Natural Resources, Kivioq 2, 3900 Nuuk, Greenland
3
Geological Survey of Denmark and Greenland, Oester Voldgade 10, 1350 Copenhagen K, Denmark*presenting author: pefi@aqua.dtu.dk

In this study, we investigate movement and structure of capelin (Mallotus villosus) stocks inGreenland by otolith microchemistry. Capelin is an essential species in the food chains of many
marine ecosystems, but little is known about its stock composition and migratory behavior inGreenland. Such knowledge is crucial for proper management of the species, both in terms ofsustainability and economy. During late spring and early summer, large schools aggregate inGreenland fjords all along the coastline, where they spawn in shallow water. However, their spatial
movement the rest of the year is largely unknown, with some residing in the fjords while others
may migrate offshore. In this study, we tested for the following: 1. If separate capelin stocks exist
and, if so, to what degree mixing between them occurs; 2. If individual fish exhibit natal homing
for spawning; 3. If migration between fjords and offshore environments occurs. In preparation forthis study, 50-80 spawning capelin were caught at each of 21 different localities along Greenland's
West-, South- and East coast. From each locality, otoliths were removed from ~35 fish that
predominantly belonged to the 2013 year class. To discriminate between stocks at different
localities, microchemical patterns in the otoliths were analyzed using LA-ICP-MS on core-to-edgetransects. Otolith microchemistry depends amongst others on ambient water chemistry, and canbe used to trace parameters such as temperature, salinity and local geological discharge. We
tested for patterns in element-to-calcium ratios of the elements Sr, Ba, Mg, Mn, Li, Cu, P, K, Ti, Zn
and Pb. Two of the involved localities were situated near previously active lead-zinc-mines, which
could allow for a Pb-Zn signal to be traced in fish from these and adjacent localities. Results
indicate that different localities can be discriminated based on otolith chemistry, both forindividual localities and on a larger scale, by which Greenland’s coastline can be divided into
different zones with distinct geochemical signatures, allowing us to track migration and identify
different stocks.

Session: Fisheries Ecology and Management45

5th International Sclerochronology Conference, ISC 2019

Shell sclerochronology and stable oxygen isotope ratios fromthe limpet Patella depressa Pennant, 1777: Implications forpalaeoclimate reconstruction and archaeology in northern
Spain
Asier García-Escárzaga1,2*, Igor Gutiérrez-Zugasti3, Manuel R. GonzálezMorales3, Javier Fernández-Eraso2, Patrick Roberts1
1

Max Planck Institute for the Science of Human History. Kahlaische Strasse 10. D-07745 Jena, Germany
Department of Geography, Prehistory and Archaeology, University of the Basque Country, C/ Tomás y Valientes/n, 01006, Vitoria-Gasteiz, Spain
3
Instituto Internacional de Investigaciones Prehistóricas de Cantabria (Universidad de Cantabria, Gobierno de
Cantabria, Grupo Santander), Edificio Interfacultativo de la Universidad de Cantabria, Avda. Los Castros s/n.
39005. Santander, Spain
2*presenting author: a.garcia.escarzaga@gmail.com

Palaeoclimate studies in archaeology are increasingly focusing on methodologies that enable highresolution insights into seasonality, a primary parameter dictating human foraging strategies andresilience. In areas such as Spain, where hunter-gatherers have utilised coastal resources
throughout the Pleistocene and Holocene, stable oxygen isotope ratios of mollusc shells found inarchaeological sites offer the possibility of reconstructing coastal resource exploitation patterns
and changing in marine conditions of direct relevance to past hominin. However, this method
relies on the fact that 1) shell carbonate is deposited by the molluscs in equilibrium with thesurrounding environment and that 2) actualistic investigation of modern specimens validate that
selected species can be used as accurate palaeoclimate indicators. While previous investigationsin the Cantabrian region (northern Spain) have focused on topshells Phorcus lineatus (da Costa,
1778) and limpets Patella vulgate Linnaeus, 1758 as effective seawater palaeothermometers, thelimpet Patella depressa Pennant, 1777, one of the most represented mollusc species in thearchaeological assemblages during the Holocene in the Atlantic Europe, has been very scarcely
studied as a climate proxy. Here we explore the possibility that this species can be used as aneffective climate proxy in this region. We collected modern samples of the limpet P. depressa from
Cantabria throughout the course of a year. A sclerochronological investigation combining stable
oxygen isotopes and growth pattern analysis was conducted in order to determine if δ18Oshellare
mainly temperature dependent and also to accurately establish P. depressa annual growth
patterns.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

46

5th International Sclerochronology Conference, ISC 2019

Using hard structure chemistry and growth increment
chronologies to investigate partial migration: implications
for fisheries management
Bronwyn M. Gillanders1*, Christopher Izzo2
1
2

School of Biological Sciences, University of Adelaide, SA, Australia
Fisheries Research and Development Corporation, Adelaide, SA, Australia*presenting author: bronwyn.gillanders@adelaide.edu.au

Migration shapes the distribution of animals in space and time and is widely seen in the animal
kingdom. As animals strive to survive and maximise their fitness, a number of strategies have
evolved including partial migration, or intrapopulation variation in migratory tendency. Under
such a scenario a component of the population migrates and a component remains resident within
a single habitat throughout the year. Although ubiquitous among many animals, partial migration
remains relatively understudied with little empirical research addressing its consequences. The
chemical patterns in hard structures and the temporal context in which they have formed provide
an opportunity to not only elucidate individuals within a population that migrate versus those thatremain resident, but also to investigate potential consequences, for example on growth. Our aim,
focusing on fish, is to use elemental signatures in ear bones (otoliths) to categorize fish as either
resident or migratory and then to determine continuous seasonal or annually resolved growth
histories of each contingent type. All three species (black bream, mulloway, greenback flounder)
investigated showed differences in proportion of fish categorized as migratory versus resident
based on chemical chronologies. Although average growth was often similar between resident
and migrant fish, year to year variation varied significantly. Migration type (resident versus
migratory) often significantly improved model fit compared to models with just year- and agerelated growth trends. Results suggest potential population level bet hedging for some species
with dynamism in growth likely driving persistence of both life-history types. Such complex
relationships in growth between resident and migratory contingents suggests that managementof species exhibiting partial migration will be challenging, especially in a world subject to achanging climate.

Session: Fisheries Ecology and Management47

5th International Sclerochronology Conference, ISC 2019

Developing subannual isotope records from fingernail-sizedshells from Antarctic coastal waters
Alejandro Román González1*, Ian Hall1, James Scourse1, Paul Butler1, Lloyd
Peck3, Michael Meredith3, Hugh Venables3, Caroline Lear2
1

University of Exeter, Penryn Campus, Penryn, Conrwall TR10 9FE, UK
School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Pl, Cardiff, CF10 3AT, UK
3
British Antarctic Survey, High Cross, Madingley Rd, Cambridge, CB3 0ET, UK
2*presenting author: a.roman-gonzalez@exeter.ac.uk

Stable oxygen and carbon isotope records (δ18O and δ13C) are a commonly used proxies insclerochronology to understand environmental drivers of shell growth. These proxies become
especially important to stablish baselines when instrumental data is sparse or non-existent. The
Southern Ocean is a clear example of this, where collecting instrumental data series is challenging,
expensive and often they are carried out only during short periods of time. In particular, the West
Antarctic Peninsula (WAP) region has been the focus of scientific interest since has been
experiencing the strongest warming in the southern hemisphere over the last half of the 20th
century. We present here the first multiannual stable oxygen and carbon isotope records withseasonal resolution of the shallow Antarctic bivalve Aequiyoldia eigthsii collected from the South
Orkney Islands and from the WAP from modern and historical collections. Since this is the firsttime that these records have been developed for this species we present the annual andsubannual variability and uncertainties in the records. In addition, we present the technique used
for drilling this particularly fragile and thin shells, which may help colleagues working with similar
specimens. A detailed comparison of the stable isotope records with the long-term Rothera
Biological Instrumental Series (RaTS) is presented. δ13Cshell records capture major ecologicalchanges that occurred in Ryder Bay (WAP) between 2007/8, when a shift from high to low yielding
blooms occurred. An offset between the seasonal averaged δ18Oshell and the δ18Owater was
identified, a linear model was used to produce a synthetic δ18Oshell record to calculate thedifferences in temperature and salinity for such offset. A possible explanation of the cause of thisoffset is the influence of coastal meltwater runoff in the coastal salinity by the creation of surface
hyposaline water lenses.

Session: Climate and Oceans: Past, Present and Future48

5th International Sclerochronology Conference, ISC 2019

Sclerochronological study in the Arabian Peninsula: growth
pattern calibrations on modern bivalves and archaeologicalapplication from shell middens
Marc Gosselin1*, Catherine Dupont1, Sophie Méry1, Jean-François Berger2
1

CNRS, UMR 6566 CReAAH « Centre de Recherche en Archéologie Archéosciences Histoire » Université deRennes, 35000 Rennes, France
2
CNRS, UMR 5600 EVS, IRG, Université Lyon 2, 69676 Bron, France*presenting author: a.roman-gonzalez@exeter.ac.uk

Numerous mollusc shell middens exist along the coasts of the Arabian Peninsula. It is theconsequence of human occupations during Mid-Holocene and suggests that resources frommarine environment played a significant part in their diet and/or daily activities. However,uncertainty remains about the perennial or seasonal occupation of such coastal sites.
Sclerochronology can assess such hypothesis by studying the season of catch of those bivalves. To
this end, three Veneridae species regularly found in shell middens of United Arab Emirates andSultanate of Oman were selected. As the biology of those species is poorly known, we first
conducted in situ experiments on modern specimens in order to access their respective growth
rhythms and thus to understand their shell growth patterns within their surrounding environment.
Those findings were then applied to archaeological specimens from different Arabian shell
middens (6.200-4.300 BC) as a way to investigate spatial-temporal patterns of human occupation
as well as insight into environmental variability. This work was supported by the ANR project
NéoArabia (ANR-16-CE03-0007) and the French Archaeological Mission to the UAE.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

495th International Sclerochronology Conference, ISC 2019

Unravelling the biology of conodonts (early vertebrates)
through sclerochronology of their skeletal tissues
Bryan Shirley1, Madleen Grohganz1*, Michel Bestmann1, Emilia Jarochowska1
1

GeoZentrum Nordbayern, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany*presenting author: madleen.grohganz@web.de

Conodonts are extinct jawless, eel-like vertebrates common in marine facies from the Cambrianto the Triassic periods. Despite their wide use in biostratigraphy and paleoclimatology, little is
known about their actual biology. Conodonts were the first vertebrates to produce mineralized
skeletal tissue. Their microscopic teeth analogues, called elements, are composed of an apatiteorganic composite biomineral and grew through outer periodical accretion of new growthlamellae. To analyze physical and chemical variations across their accretionary lamellar tissue, thinsections through individual conodont elements were prepared. With the help of our highresolution BSE imaging technique, alternations of dark and light bands forming the conodont
growth lamellae were made visible. This technique provides a new way to analyze conodont
growth dynamics and determine distinct growth stages. Additionally, geochemical EDX analyses
were carried out across the lamellar tissue of the different growth stages. These stages are linked
to distinct geochemical changes, mainly of the element strontium. Sr concentration relative to Ca
acts as an indicator of the trophic position, on which an organism is situated. The higher anorganism is situated in the trophic network, the more depleted its tissue will become in Sr. This
relationship is mainly observed in terrestrial mammals, but is also hypothesized for marineorganisms. Therefore, the observed changes in Sr might reflect a transition in the conodont’s
mode of feeding and/or living. The early life stage of the conodont is characterized by a thin,elongated morphology, the lack of wear patterns and high Sr values. These observations lead tothe interpretation as the first, larval stage, during which the conodont fed on lower trophic levels.
Based on the observation of following patterns of wear and periodic repair, as well as low Srvalues, a drastic change in the conodont’s mode of living towards a more mature type of feeding,possibly as a predator or scavenger, is proposed. This study shows that applying
sclerochronological methods to analyze the succession of growth lamellae in conodonts canprovide valuable information about the biology, especially the mode of living and/or feeding, ofthese enigmatic animals.

Session: Paleoecology and Evolution50

5th International Sclerochronology Conference, ISC 2019

Seeking the true time: Exploring otolith chemistry as an agedetermination tool
Yvette Heimbrand1*, Karin Limburg1,2, Karin Hüssy3, Rajlie Sjöberg1, Anne-Marie
Palmén Bratt1, Svend-Erik Levinsky3, Anastasia Karpushevsky4, Krzysztof
Radtke5, Jill Öhlund6, Eva Kylberg6
1

Swedish Institute of Marine Research, Swedish University of Agricultural Sciences, Turistgatan 5, Lysekil 453 30,
Sweden2
SUNY College of Environmental Science and Forestry, United States
3
National Institute of Aquatic Resources, Technical University of Denmark, Jaegersborg Alle 1, Charlottenlund
2920, Denmark
4
Atlantic Research Institute of Marine Fisheries and Oceanography (AtlantNIRO).5 Dm. Donskoy Street,
Kaliningrad, Russia
5
National Marine Fisheries Research Institute, Ul. Kollataja 1, 81-332 Gdynia, Poland
6
Swedish Museum of Natural History, Stockholm, Sweden*presenting author: yvette.heimbrand@slu.se

Otoliths are calcified structures in bony fishes’ sensory and balance system with chronometricproperties, often used for age and growth rate estimation in fisheries management. Unclear
seasonal growth zones in otoliths of the Eastern Baltic Sea cod stock have resulted in unreliable
age determination and impaired analytical assessment. An age estimation experiment was set up
to compare conventional age reading with a new micro-chemical method, assessing seasonalpatterns in trace elemental otolith uptake. We examined chemical profiles of various elemental
ratios that were expected to display seasonal peaks and valleys, either due to differences ingrowth (higher in summer) or environment (e.g., movement into colder, saltier, less hypoxic waterin winter). Images of transverse cross sections of otoliths from the Baltic and North seas, collectedduring the last four decades were uploaded into the age reading platform SmartDots. Six experts
at reading cod otoliths used visually recognizable features in the otolith images to annotate annuli
along a pre-drawn transect from the core to the dorsal edge. Three chemical readers annotatedannuli based primarily on chemical profiles which were provided separately. A ranking scale wasdeveloped to assess both otolith image readability and how well the chemical profiles reflectedseasonality. The outcome of the age experiment revealed higher precision (coefficient ofvariation) and percentage agreement for the chemical method than for the conventional method.
The highest ranked trace elements for reflecting seasonality i.e. age were Mg and P, both proxies
for growth. The image opacity of the three first annotated annuli on each otolith also varied
between methods. Conventional readers tended to select darker translucent areas whereas
chemical readers placed the annuli on brighter, opaque parts of the otoliths, suggesting inverse
formation of growth zones. These promising results show potential to validate age and growthrate estimations, improve the certainty and quality of the analytical assessment, and hence
management of the Eastern Baltic cod stock.

Session: Fisheries Ecology and Management51

5th International Sclerochronology Conference, ISC 2019

A novel study combining sclerochronology andbiogeochemical modelling to understand mechanisms
controlling bivalve growth on the North West European shelf
Sarah Holmes1*, Paul Halloran1, Paul Butler3, Johan van der Molen2, John
Aldridge3, Chris Perry11Department of Geography, University of Exeter, UK
Royal Netherlands Institute for Sea Research (NIOZ), NL
3
Center for Environment, Fisheries and Aquaculture Science (CEFAS), UK
2*presenting author: s.holmes@exeter.ac.uk

Of all marine proxies available, sclerochronology (the study of the growth bands on long-lived
marine clams) is the only one that provides absolutely-dated, multi-centennial, annually-resolved
archives of past ocean environment, analogous to dendrochronology. Shell growth has beenshown to be a function of temperature and food availability and many studies have demonstrated
that these records are also capturing a number of related environmental variables including SSTs,
air temperature, productivity and wider-scale climate patterns such as AMO (Atlantic
Multidecadal Oscillation) and NAO (North Atlantic Oscillation); however, the exact mechanisms ofshell growth are yet to be fully understood.
Recent in situ and laboratory experiments have been fundamental in disentangling thesemechanisms but the factors that drive or hinder growth within the ecosystem and the wider
environment still need to be studied in greater detail and across the vast habitat range of species
such as Arctica islandica. However, attempts to do so are hampered by scarce long-term
instrumental records. Bottom water time series (where clams live) are extremely rare andmoreover, only a limited number of variables are measured - important biogeochemicalparameters are often omitted. Other options must be explored.
For the first time, this PhD research is attempting to use biogeochemical models alongsidesclerochronology records to explore the mechanisms behind shell growth. Ecosystem models suchas the European Regional Seas Ecosystem Model (ERSEM) contain a vast number ofhydrographical, chemical and biological variables and have been shown to simulate the shelf sea
environment with a good degree of accuracy. This research compares multiple sclerochronologies
across the North Sea with 1D hindcasts of ERSEM and works towards understanding theirrelationships by running novel experiments within the 1D model such as controlling (or evenblocking) meteorological inputs.
This talk will present results of these experiments. For example, a key finding has been that using
the model, we have been able to mechanistically attribute bivalve growth variability to wind speed
variability. From this we can infer that the primary control on the ecosystem (as represented bymodelled bivalves) is still of natural climate variability rather than anthropogenic change. It is clearthat in addition to furthering the field of sclerochronology, the proxy-model fusion approach cangive us greater insight into the shelf sea environment where instrumental data is lacking. Finally,
the project also has potential to provide improved predictions of future shelf sea change allowing
policy-makers to manage this vital ecosystem more effectively.

Session: Climate and Oceans: Past, Present and Future52

5th International Sclerochronology Conference, ISC 2019

The “who, when and where” of cod migrations in the
KattegatKarin Hüssy1*, Christoffer Moesgaard Albertsen1, Tonny Berndt Thomsen2,
Simon Hansen Serre2, Jakob Hemmer-Hansen11National Institute of Aquatic Resources, Technical University of Denmark, Kemitorvet, Building 202, DK-2800
Kgs. Lyngby, Denmark
2
Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K., Denmark*presenting author: kh@aqua.dtu.dk

The prerequisites for sustainable management of fish stocks is knowledge about the stocks
geographic distribution and the extent of migration between adjacent management units. In
recent decades the use of otolith chemical fingerprints for stock identification purposes has gained
increasing interest. Owing to their time-keeping properties and their lifelong record ofenvironmental history, otoliths are a useful tool for studying stock affiliation and individual fish’s
migration patterns. The Kattegat is a transition area between the North Sea and the Baltic Sea,
where environmental conditions are dominated by a pronounced horizontal salinity gradient anda coastal-type environment in the Kattegat compared to the North Sea. The cod stock in the
Kattegat consists of a mix of genotypes from both the North Sea and the Kattegat, with adecreasing frequency of North Sea cod with age. We used LA ICP-MS based data with combined
standard stock identification analyses and a regime-switching state-space model to test the
hypotheses that 1) North Sea cod are spawned in the North Sea and drifted into the Kattegat
during the early life stages, and 2) Adult North Sea cod remain in the Kattegat without return
migrations during that time. The regime-switching state-space model filters noise from signal in
the data and includes four areas of attraction to describe the migration patterns depicted in thechemical fingerprints. All parameters are estimated by maximum likelihood using an approximate
deterministic filter and smoother. Results show that North Sea cod are spawned in the North Sea
and enter the Kattegat before the end of their first winter. Elements separating the fingerprints ofthe two cod genotypes are Sr, Ba and Mn. North Sea samples were characterized by higher levelsof Sr and lower levels of Ba and Mn, consistent with the different environmental conditions in the
two areas. Consistent return-migrations on an annual basis could not be detected neither during
the juvenile nor during the adult stages. However, a small number of individuals did undertake
migrations to the North Sea and back to the Kattegat. However, there was no consistent patternin these migrations with respect to fish age or time of the year. These results demonstrate theneed for a stock assessment that takes these complex drift/migration patterns into account inorder to avoid over-exploitation of the endemic Kattegat cod stock.

Session: Growth, Bioenergetics and Ecosystems

53

5th International Sclerochronology Conference, ISC 2019

Growth rate, extinction and survival among late Cenozoic
marine bivalves of the US eastern seaboard
Andrew L.A. Johnson1*, Annemarie M. Valentine2, Bernd R. Schӧne3, Donna
Surge4, Melanie J. Leng5, Hilary J. Sloane5
1

School of Environmental Sciences, University of Derby, Derby DE22 1GB, UK
School of Geography and Environmental Science, Nottingham Trent University, Southwell NG25 0QF, UK
3
Institute of Geosciences, University of Mainz, 55128 Mainz, Germany
4
Department of Geological Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
5
NERC Isotope Geoscience Facilities, British Geological Survey, Keyworth NG12 5GG, UK
2*presenting author: A.L.A.Johnson@derby.ac.uk

The Plio-Pleistocene saw a mass extinction of marine bivalves in the western Atlantic, with some
65% loss of species. Two important pectinid genera (Carolinapecten and Chesapecten) became
extinct. These probably had a ‘siege’ strategy towards predators, favoured by rapid growth. The
evidence of microgrowth-increment size and/or oxygen-isotope ratios shows that growthoccurred rapidly in Plio-Pleistocene examples of both, in Carolinapecten at rates up to to 60%
higher than have been recorded in any other pectinid, extinct or extant. Another important
pectinid genus (Placopecten) of the US eastern seaboard survived from the Pliocene to thepresent. This has a ‘flight’ strategy towards predators, not favoured by rapid growth. In
accordance with this, growth in Pliocene examples was no faster than in modern forms, despite
conditions of high primary production (indicated by the vertebrate assemblage) which would haveenabled rapid growth. While the Plio-Pleistocene decline in primary production on the US easternseaboard would have had no effect on the growth rate and ability of Placopecten to avoid
predation, it would have impacted on Carolinapecten and Chesapecten, and may account for their
extinction. Detailed analysis of growth-rate variation in Carolinapecten in relation to production
and temperature (Johnson et al. 2019; PALAIOS 34:1-22) indicates that exceptionally fast growthrequired high production but was possible at quite low temperatures. Slow growth never occurredunder high production but was common at low temperatures. These findings suggest that while
production decline was contributory to the extinction of Carolinapecten, Plio-Pleistocene
temperature decline also played a part. However, the latter is implicated only if the low oxygenisotope temperatures associated with late, slow-growing examples of Carolinapecten are
accurate. They are contradicted by the assemblage composition of co-occurring molluscs andostracods and by the rapid growth of the co-occurring glycymeridid bivalve, Glycymeris americana,modern examples of which appear to grow at a comparable rate only under conditions of hightemperature (combined with ‘average’ production). Available evidence therefore suggests that
Plio-Pleistocene extinction of marine bivalves on the US eastern seaboard was largely due to
production decline.

Session: Paleoecology and Evolution

54

5th International Sclerochronology Conference, ISC 2019

Sclerochronological and geochemical approach for paleo
typhoon seasonality reconstruction using giant clam fossils
in Kikai Island, Japan
Taro Komagoe1*, Tsuyoshi Watanabe1,2, Keiichi Sasaki3, Kotaro Shirai4, Atsuko
Yamazaki1,5
1

KIKAI institute for coral reef sciences, Kikai town, Japan
Department of Natural History, Graduate School of Science, Hokkaido University, Sapporo, Japan3
Department of Cultural Properties and Heritage, Kanazawa Gakuin University, Kanazawa, Japan
4
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
5
Faculty of Sciences, Kyushu University, Fukuoka, Japan
2*presenting author: komataro@kikaireefs.org

Giant clam (Tridacnidae) widely distributes over the coral reefs in Indo-Pacific Ocean and has
symbiotic algae, facilitating fast growth and forming daily shell growth pattern (daily growthincrement). Thus, giant clam shell could be useful tool for high temporal resolution analysis forpast environment.
Kikai Island located in the northern Ryukyu archipelago has the well-developed coral reef terraces
with the highest uplift rate (1.8 m/ka) in Japan tracking back to that formed in marine isotope
stage (MIS) 5e (Ota et al., 2000). With this feature, late Pleistocene to Holocene giant clam shellfossil are continuously available through the period. Especially, MIS 3 has been the subject ofintense study in deep-sea cores and in ice records as it shows unusual high frequency climate
variability. Therefore, giant clam fossil in Kikai Island can provide the high temporal resolution
environment changes information through the period.
We sampled modern giant clam specimen (Tridacna maxima), Late Pleistocene MIS 3 (55ka, T.
Squamosa), and Holocene (3.9ka, and 7.2ka, T. maxima and T. Squamosa, respectively) fossil
specimens from Kikai Island. Each fossil specimen was well preserved from diagenesis alternation.
After checking diagenesis alternation, stable isotope ratio (δ18O, δ13C), Barium Calcium
concentration (Ba/Ca), and sclerochronological analysis were performed in each shell specimens.
The shell samples were milled with 300 µm width using hand drill. δ18O, and δ13C in shell specimen
were analyzed using stable isotope ratio mass spectrometer. Ba/Ca was analyzed using Laser
Ablation Inductively Coupled Plasma Mass Spectrometry andInductively Coupled Plasma Atomic
Emission Spectrometry.
δ18O and growth increment thickness in the modern shell specimen well reflected annual SST
cycles. The Ba/Ca peaks and growth reduction which characterized by disturbed growth lines insummer coincided with the typhoons approached to Kikai Island in modern specimen. As well as
modern specimen, δ18O and growth increment thickness in fossil specimen showed annual cycles.
Also, fossil specimen had growth reductions, especially, MIS 3 specimen had Ba/Ca peaks atsummer season. Growth reduction and Ba/Ca peaks in giant clam shell possibly reflects typhoon
approaches (Komagoe et al., 2018). Thus, these results suggest that Holocene and MIS 3 fossil
giant clams in Kikai Island could reveal the changes in timing and frequency of typhoons
approaching Kikai Island from Late Pleistocene to Holocene. We will discuss the relationshipbetween the typhoon signature suggested from giant clam records and mean climate at MIS3 andHolocene in the presentation.

Session: Environmental Biomonitoring & Entrepreneurship55

5th International Sclerochronology Conference, ISC 2019

Geochemistry and sclerochronology of Mercenaria stimpsoni
collected from the western North Pacific
Kaoru Kubota1*, Kotaro Shirai1, Naoko Murakami-Sugihara1, Koji Seike3,
Kazushige Tanabe4, Masayo Minami5, Toshio Nakamura5
1

Japan Agency for Marine-Earth Science and Technology, Japan
Atmosphere and Ocean Research Institute, The University of Tokyo, Japan
3
Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Japan
4
The University Museum, The University of Tokyo, Japan
5
Institute for Space-Earth Environmental Research, Nagoya University, Japan
2*presenting author: kaoryu0129@gmail.com

Bivalve shell is one of the most important archives of past environmental changes because somespecies can live more than several decades and distribute broadly (e.g., from high to low latitude,
fresh/brackish/sea water). We have investigated potential of long-lived cold water bivalve,
Mercenaria stimpsoni (Stimpson's hard clam) living in the western North Pacific (especially, coastal
area of North East Japan). In this presentation we will show sclerochlonological and geochemicalrecords (e.g., oxygen isotopes and radiocarbon) of both live-caught and dead specimens collectedfrom the seafloor of NE Japan (5–20 m). From both sclerochlonology and nuclear bomb-derived
radiocarbon (bomb-14C), it was found that this animal can live for more than 100 years, thus very
useful for paleoeanograpic studies. It was also found that a lot of M. stimpsoni were killed by hugetsunami that hit NE Japan in March 2011, which is likely caused by disturbance of marine sediment,
including seabed liquefaction.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

565th International Sclerochronology Conference, ISC 2019

Sclerochronology beyond the deepFranck Lartaud1*, Karine Nedoincelle1, Marc de Rafelis2, Olivier Bruguier3,
Nadine Le Bris1
1

Sorbonne Université, CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques, LECOB, Observatoire
Océanologique de Banyuls, F-66650 Banyuls-sur-mer, France
2
Géosciences Environnement Toulouse, UMR 5563 CNRS,UR 234 IRD,UM 97 UPS,Observatoire Midi-Pyreńeés,
CNES, 14 avenue Édouard Belin, 31400 Toulouse, France
3
Géosciences Montpellier, Université de Montpellier – CNRS, 2 Place E. Bataillon, 34090 Montpellier Cedex 5,
France*presenting author: franck.lartaud@obs-banyuls.fr

Sclerochronology is widely used in marine coastal environments but still in its infancy in the deepsea, although biogenic carbonates are classically the only support for characterization of climate
and oceanographical changes in theses habitats. The difficulties of accessing to deep-sea
ecosystems and the lack of temporal calibration in skeleton biomineralization of species living in
the deep-sea explain partly this gap. But the use of underwater vehicles allows now insitu experimentation facilities. Through the shell growth and geochemical signal analysis ofchemosynthetic mussels from mid-oceanic hydrothermal systems, we demonstrate theparamount contribution of sclerochronological approaches to investigate both the ecology of ventspecies and the environmental dynamic.
(1) Mussel growth is related to semi-diurnal and spring-neap fluctuations of abiotic conditions
exposing the organisms to the alternance of oxic and sulfidic conditions. Periods associated withthe absence of hydrodynamic fluctuations strongly limit growth, suggesting that periodical
changes in the habitat conditions are essential for those species.
(2) The carbon isotopic signature of the shells is primarily controlled by the local dissolved
inorganic carbon, but the types of chemosynthetic pathways (i.e., methanotrophic or thiotrophic)
produce a 13C fractionation in the shell with respect to seawater. Mussels associated to sulfideoxidizing symbiosis display higher δ13C than expected by the isotopic equilibrium. This suggeststhat shell carbon isotopes are a reliable proxy in the symbiosis activity, including at micro-habitat
scale, and can be used to reconstruct the trophic pathways in fossil hydrothermal systems.
(3) As Mg/Ca in hydrothermal fluids are severely depleted in magnesium, mussels used a stable
content of Mg from seawater to form their shells making the shell Mg/Ca ratio a promisingthermometer proxy in hydrothermal vent ecosystems.
Deep-sea ecosystems constitute thus new opportunities and challenges for sclerochronologicalworks giving atypical environments to test the applicability of geochemical proxies.

Session: Proxy Development: Challenges and Opportunities

57

5th International Sclerochronology Conference, ISC 2019

Can otolith δ18O of tagged fish informed about migration
behaviors and population structure of European sea bass in
the North East Atlantic?
Emilie Le Luherne1,2*, Françoise Daverat2, Mathieu Woillez1, Hélène De
Pontual1
1
2

IFREMER Brittany Center, Plouzané, FRANCEIRSTEA Bordeaux, Cestas, FRANCE*presenting author: Emilie.Le.Luherne@ifremer.fr

European sea bass, Dicentrarchus labrax, is – especially in France – a key species for bothrecreational and commercial fisheries. Recent stock assessments have shown a decline of sea bass
wild population. For a better understanding of the population structure, IFREMER has carried out
since 2014 a large-scale electronic tagging programs targeted on adult fish that have alreadyprovided more than 30 % of recovery in late 2018. From Dunkirk to Cap Breton, 1 220 sea bass
were equipped with data storage tags (DSTs), with temperature and pressure sensors and a typicalbattery life of 2 years. Individual migration histories reconstructed from the recovered DSTs haveyield evidence of sea bass fidelity to winter spawning areas in the northern region (English
Channel/Celtic Sea) and in the Bay of Biscay. This finding raises new questions on the underlying
mechanism of fidelity to spawning areas: is that behavior associated to natal homing or social
learning mechanisms? The aim of the present study is to clarify the underlying mechanism offidelity to spawning areas from coupling for the same fish, migration histories obtained from DSTs
and the analysis of individual histories retrieved from otoliths. The isotopic composition of oxygen(δ18O) in otoliths has been largely used as a proxy of temperature. Therefore, it was chosen as arelevant tool to differentiate the English Channel/Celtic Sea stock and the Bay of Biscay stock. To
assess both the spatial and analytical precisions required for these analyses, δ18O were measured
using Secondary Ion Mass Spectrometry. δ18O signatures were analyzed at three life periods : (1)the larval period, (2) the spawning periods with corresponding temperatures from DSTs and (3)the spawning periods without corresponding temperatures from DSTs (i.e. before tagging and post
tagging for fish with more than 2 year at liberty).The coupling of temperatures from DSTs andotoliths oxygen isotope signatures allows us (i) to calibrate the relation between sea temperatureand oxygen stable isotope in otoliths of sea bass and then (ii) to explore the underlying mechanismof sea bass fidelity to spawning areas. Improvement in the understanding of sea bass fidelity tospawning areas and potential exchanges between these two stocks will provide relevant
information for sea bass assessment and management.

Session: Fisheries Ecology and Management58

5th International Sclerochronology Conference, ISC 2019

Stable isotope investigations of Later Stone Age shellfishingand local climate shifts on the South African west coast
Emma Loftus1*, Julia A Lee-Thorp2, Judith Sealy3
1McDonald Institute for Archaeological Research, University of Cambridge, Cambridge, UK
Research Laboratory for Archaeology, University of Oxford, Oxford, UK
3
Department of Archaeology, University of Cape Town, Cape Town, South Africa
2*presenting author: el485@cam.ac.uk

Coastal hunter-gatherer occupation of southern African shores spans tens of thousands of years,
and has accumulated valuable repositories of seasonal climate and human behavioural data, inthe form of long-sequence archaeological shell-middens. We present a modern geochemical study(serial stable carbon and oxygen measurements) of the limpet Cymbula granatina, from locations
upstream and downstream of a large, summer upwelling cell, demonstrating the utility of thisspecies for palaeoclimate and seasonality studies. We also investigate the appropriate scale ofsampling for this relatively fast-growing species, given the temporal span and archaeologicalresearch questions. Regional shifts in sea surface temperature and upwelling activity arereconstructed from several radiocarbon-dated sites across the Holocene, and correlated withshifts in the cultural record from the region. We examine the scheduling of hunter-gatherer
shellfishing, including from both rockshelter and open-air “megamidden” contexts, anddemonstrate a persistent pattern of winter shellfish harvesting, similar to that observed along thesouthern coast during the Holocene Later Stone Age, in spite of marked ecological differences
between the regions.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present595th International Sclerochronology Conference, ISC 2019

High-resolution oxygen isotope records from fish and shellremains, Lake Kutubu, Papua New Guinea
Kelsie Long1,2*, Simon Haberle1,2, Larissa Schneider1,2, Rachel Wood2,3, Stewart
Fallon2,3
1School of Culture, History and Language, ANU, Australia
ARC Centre of Excellence for Australian Biodiversity and Heritage, ANU, Australia
3
Research School of Earth Sciences, ANU, Australia
2*presenting author: kelsie.long@anu.edu.au

Lake Kutubu is a thermally stratified freshwater lake, situated in the southern highlands provinceof Papua New Guinea. The lake is oligomictic, exhibiting thermal and chemical stratification withrare periods of circulation at irregular intervals. The region derives its high annual rainfall from theNorthwest Monsoon and Southeast Trade Winds throughout the year and is sensitive to changes
in the strength of Indian Ocean Dipole and El Niño-Southern Oscillation.
Here we focus on exploring the potential for deriving a long-term and continuous stable isotope
record from fish remains preserved in Holocene sediments cores from Lake Kutubu. The main aimof the project is to expand our understanding of past palaeoclimate drivers, landscape dynamics
and lake system productivity, all of which would have influenced patterns of human occupation,
dispersal and environmental interactions through time.
The first part of the project explores the relationships between isotopic changes in modern fish
remains and known lake conditions. We measured oxygen isotopes across the age increments ofmodern fish otoliths collected from Lake Kutubu, using the Sensitive High Resolution Ion
Microprobe (SHRIMP). Freshwater snail shells from the upper layers of the lake sediment cores
have also been analysed for oxygen isotope ratios, to determine if any past fluctuations in ambientconditions are preserved. Here I will present the results of these initial oxygen isotope
measurements and discuss their relationship to ambient lake conditions, known climatic eventsand the possibilities of extending the record further back in time using fish scales and bones
preserved in lake sediment cores.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

605th International Sclerochronology Conference, ISC 2019

A 250 year chronology of Arctica islandica in the MidAtlantic region of the US continental shelf
Roger Mann1*, Eric Powell2, John Klinck3, Sara Pace2, Matthew Long1, Theresa
Redmond1, Khalil Russell4
1

Virginia Institute of Marine Science, Gloucester Point VA 23062, USA
Gulf Coast Research Laboratory, University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS
39564, USA
3
Department of Ocean, Earth, and Atmospheric Sciences, Center for Coastal Physical Oceanography, 411
Monarch Way, Old Dominion University, Norfolk, VA 23529, USA
4
Department of Biology, College of William and Mary, P.O. Box 8795, Williamsburg VA 23187-8795, USA
2*presenting author: rmann@vims.edu

The presence of the ocean quahog Arctica islandica in the Mid-Atlantic region of the UScontinental shelf represents the most southerly extension of the species distribution. The region
is notable for the presence of both a large annual surface temperature range that reaches
subtropical summer maxima in combination with an intense seasonal thermocline that overlays a“cold pool” of water. A. islandica is restricted to the depths of the cold pool, and its biology is both
intimately related to and records the dynamics of this oceanographic feature. Additionally, thepopulation, with a standing stock estimated at several million tonnes, is subject to a sustainably
managed fishery. Herein we review a near decade of effort examining population age structure,mortality, and recruitment of this extraordinary population in addition to the large terminal sizeof many individuals, in some instances exceeding 130 mm shell length. The Mid-Atlantic iswarming, as noted by the changing distributions of both finfish and benthic dominants including
A. islandica. We describe the response of the population to changing climate from the end of the
Little Ice Age through the present, and note a continuing increase in growth rates over the past
century in combination with a gradual retreat into greater depths as summer warming impacts
the shallow, inshore limit of the Mid Atlantic seasonal cold pool.

Session: Climate and Oceans: Past, Present and Future61

5th International Sclerochronology Conference, ISC 2019

Glycymeris pilosa - spatial and temporal insight into
differences of trace element records
Krešimir Markulin1*, Melita Peharda1, Regina Mertz-Kraus2, Hana Uvanović1,
Bernd R. Schöne2
1Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia
Institute of Geosciences, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 21, 55128 Mainz,
Germany
2*presenting author: markulin@izor.hr

Investigation of the geochemical composition of bivalve shells can provide information on changes
in the marine environment occurring during the organism's lifespan. High spatial and temporal
resolution element records can be obtained through laser ablation inductively coupled plasma
mass spectrometry (LA–ICP–MS). Glycymeris pilosa was chosen as target species as it has a lifespanexceeding 50 years and presents a potential archive of decadal climate variability. These shells
contain annual growth increments which are visible in cross-sections enabling temporal
positioning of geochemical data obtained from different shell portions. Bivalves were collected
alive by SCUBA diving at six localities along the Eastern Adriatic coast including Barbariga, Istria in
the North Adriatic Sea, Pag Island, Pašman Island, at the mouth of the river Cetina in the Central
Adriatic as well as Živogošće and Drače in the Southern Adriatic.
In this study we applied LA–ICP–MS in line scan mode to determine the trace element composition
along the major growth axis in the hinge area of the shell to obtain high-resolution profiles of
Na/Ca, Mg/Ca, Sr/Ca, and Ba/Ca. From each locality, a minimum of three similar-sized specimens
were selected for the chemical analysis. To study how trace element patterns compare amongindividuals from the same locality and among different sites along the Eastern Adriatic coast in
more recent times, three ontogenetically young (<15 years) specimens were chosen. For the moredistant past, three larger, ontogenetically older (>50 years) specimens from localities near Istria
and Drače were studied.
Time-series of Na/Cashell, Mg/Cashell and Sr/Cashell display characteristic cyclic variations with
Na/Cashell minima and Mg/Cashell and Sr/Cashell maxima occurring near annual growth lines.
Ba/Cashell time-series show noncyclic sharp peaks that vary between years and among localities.
Furthermore, time-series of Na/Cashell, Mg/Cashell and Sr/Cashell can be used to validate thepresence of annual growth lines used to build chronologies, while Ba/Cashell time-series vary along
the Eastern Adriatic coast and probably reflect local environmental changes.
Research has been supported by the Croatian Science Foundation under the project SCOOL (IP2014-09-5747).

Session: Proxy Development: Challenges and Opportunities

62

5th International Sclerochronology Conference, ISC 2019

Daily growth chronologies in a marine flatfish during
estuarine colonization
Filipe Martinho1*, Ana Vaz1, Ana Lígia Primo1, Miguel A. Pardal1, Bronwyn M.
Gillanders2, Rita P. Vasconcelos3, Susanne E. Tanner4, Patrick Reis-Santos2,41

Centre for Functional Ecology - CFE, Department of Life Sciences, University of Coimbra, Calçada Martins deFreitas, 3000-456 Coimbra, Portugal
2Southern Seas Ecology Laboratories, School of Biological Sciences, The University of Adelaide, SA 5005,
Australia
3
IPMA – Instituto Português do Mar e Atmosfera, Rua Alfredo Magalhães Ramalho, 6, 1495-006 Lisboa,
Portugal
4
MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências, Universidade de Lisboa, 1749-016
Lisboa, Portugal*presenting author: fmdm@ci.uc.pt

Marine fishes display among the most extreme spatial and temporal variability in population
dynamics, given that several transitions during their ontogenic development co-occur withchanges in habitat use. This is the case of many marine flatfishes, whose early life cycle involves
the transition between coastal areas as larvae, metamorphosis and then benthic settlement inestuaries, during which growth is driven by both intrinsic and extrinsic conditions. While thedevelopment of growth chronologies has greatly increased our understanding of the effects ofclimate on fish growth over large temporal scales, this methodology has not yet been
implemented to assess daily growth variations on fish early life history stages, during which
migrations, metamorphosis and other ecological changes may further hamper our understandingof species-environment relationships. In this work, we used otolith daily increment widths (as aproxy for individual growth) of a juvenile marine flatfish - European flounder Platichthys flesus,
from the Mondego estuary nursery (Portugal). We used increasingly complex mixed models topartition intrinsic (age and early life stage – pelagic, benthic) and extrinsic (environment:
temperature, river flow) factors to explore the importance of different environmental andphysiological drivers to individual growth in different life stages and over five recruitment cohorts(2011-2015). Additionally, we included otolith chemical composition (Sr:Ca and Ba:Ca ratios) as anatural proxy for habitat use, and whose incorporation of elements in the otolith matrix is also
influenced by the environment and physiology. Unraveling these processes is particularly complex
in estuarine environments where environmental conditions vary on small spatial and temporalscales. Results contribute to disentangling environmental and life stage driven growth patterns,
which can contribute to a better understanding of juvenile fish habitat use patterns and estuarine
nursery role.

Session: Growth, Bioenergetics and Ecosystems

63

5th International Sclerochronology Conference, ISC 2019

Reconstructing the upper-ocean 13C Suess-effect using highresolution sclerosponge records and implications for theoceanic CO2 sink
Malcolm McCulloch1*, Amos Winter2, Manuel Rigo3, Clark E. Sherman4, Julie
Trotter11

Ocean Graduate School and Oceans Institute, The University of Western Australia, Crawley, Australia
Earth and Environmental Systems Department, Indiana State University, Terre Haute, Indiana, USA
3
Dipartimento di Geoscienze, Università degli Studi di Padova, 35131 Padova, Italy
4
Department of Marine Sciences, University of Puerto Rico at Mayaguez, Mayaguez, Puerto Rico
2*presenting author: Malcolm.McCulloch@uwa.edu.au

Here we use the distinctive d13C Suess-effect signature from fossil-fuel burning preserved in thearagonite skeleton of long-lived Caribbean sclerosponges (Ceratoporella nicholsoni) to constrain
the efficacy of the oceanic sink for CO2 over the Anthropocene. The oceans play a key role indetermining the habitability of our planet, absorbing nearly 30% of the CO2released by fossil-fuelburning and other human activities. However, their ability to continue to absorb anthropogenic
CO2 at historic rates is under increasing question as atmospheric concentrations continue theirseemingly inexorable rise. Furthermore, the oceans carbonate ion concentration, and hence
buffer capacity, is declining due to ocean acidification, compounded by the reduced solubility of
CO2 in seawater as upper-ocean temperatures rise.
Sclerosponges are an ideal archive for reconstructing the oceanic uptake of anthropogenic CO2
since they are long-lived organisms whose carbonate skeleton is precipitated with a near constantd13C fractionation factor relative to the dissolved inorganic carbon of seawater (e.g. Böhm et al.,EPSL 1996). Here we also utilise sensitive high-resolution MC-ICPMS U-series dating enabling
precise, absolute chronologies to be determined. For high U sclerosponges (4-6 ppm), accurate
chronologies are mainly limited by uncertainties in corrections for non-radiogenic 230Th
incorporated during calcification (e.g. Rosenheim, et al., GCA, 2007). To overcome this limitation,
we also extracted samples from the uppermost 2-3 mm of growth surface for which ages can be
independently inferred by the date of sample collection. This now enables reliable corrections for
initial 230Th/232Th, facilitating near-annual resolution in skeletal chronologies.
Using these highly accurate sclero-chronologies we find that, regardless of water depth (30-90 m),
the combined sclerosponge d13C records closely mirror changes expected from the oceanic uptakeof isotopically distinctive d13C released into the atmosphere over the Anthropocene. From 1750
to 1850, when atmospheric CO2 concentrations were only marginally above pre-industrial levels(i.e. ~280±5 ppm), d13C ratios show relatively little change, consistent with natural variability (i.e.
±5 ppm). However, from the 1850’s to present-day (2010), there is an excellent correlation (r2 =0.995) between declining sclerosponge d13C and rising atmospheric levels of CO2, indicative of aconstant rate of uptake by the oceans of isotopically distinctive anthropogenic-derived carbon.
This contrasts to the more disparate ice-core records of changing atmospheric d13C. Our findings
thus provide a rare ‘good-news’ story, implying that the oceanic sink for anthropogenic CO2 is still
relatively stable, with uptake remaining proportionate to increasing atmospheric pCO2.

Session: Climate and Oceans: Past, Present and Future64

5th International Sclerochronology Conference, ISC 2019

Endolithic cyanobacteria: a complication for the study of
ecology and sclerochronology
Christopher McQuaid1*, Aldwyn Ndhlovu1, Cristian Monaco1, Gerardo Zardi1
1Dept of Zoology and Entomology, Rhodes University, Grahamstown 6140, South Africa*presenting author: c.mcquaid@ru.ac.za

Sclerochronology is an invaluable tool in marine ecology that depends on shell structure that islargely uncorrupted. Endolithic organisms, including photosynthetic cyanobacteria, are aubiquitous problem for marine organisms with calcified shells as they can cause extensive shelldamage. This can introduce problems as bioerosion can interfere with the determination of
growth lines. In intertidal mussels, endolithic infestation can lead to shell collapse and mortality
and even in less extreme cases, endoliths can cause a range of sub-lethal effects as energy must
be re-routed to deal with shell damage. We examined the effects of endolithic infestation onmussel energy budgets and thermal biology. We found that, while infestation did not affectammonium excretion, feeding rates or tolerance of heat stress, it reconfigures the overall energy
budget by increasing metabolic rates while reducing growth and gonad production. At the sametime, deposition of excavated CaCo3 on the outside of the shell alters the shell albedo orreflectivity, leading to reduced body temperatures and, under extreme conditions, decreased
mortality through heat stress.
Levels of infestation depend on a wide range of factors ranging from large to small scales. These
include factors affecting cyanobacterial community composition, such as latitude andbiogeography, as well as cyanobacterial biology, such as shore aspect with respect to insolationand topographic shading. Because initial infestation depends on damage to the periostracum of
the shell through wave or sand abrasion, levels of infestation are also affected by height on the
shore, the degree of wave action and host age, while differences among host species inperiostracum thickness and structure are reflected in their susceptibility to endolithic infestation.
In the case of invasive species, immunity to endoliths can offer an example of enemy-free spacein the invaded locality. Overall, endoliths have complex relationships with their host species,
affecting their ecology and introducing complications to the application of sclerochronology totheir hosts.

Session: Growth, Bioenergetics and Ecosystems

65

5th International Sclerochronology Conference, ISC 2019

Temperature-induced mineralogical transformations ofaragonitic mollusc shells
Stefania Milano1,2*, Gernot Nehrke2
1

Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103
Leipzig, Germany
2
Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany*presenting author: stefania_milano@eva.mpg.de

Mollusc shells are complex biomineralized structures mostly composed of calcium carbonate(CaCO3) and organic macromolecules. Their hierarchical organization and the coexistence of an
inorganic and an organic phase make the shells particularly resistant to mechanical and chemical
stress. For this reason, mollusc shells are abundant in geological and archaeological contexts andthey are often used as paleoenvironmental records. However, despite a general elevatedpreservation potential, shells can be subjected to diagenetic alterations. These processes can alter
their mineralogical, structural and chemical properties potentially undermining the paleoclimate
reconstruction reliability. In particular, aragonite, being a metastable CaCO3 polymorph, isespecially prone to transform into calcite. The aim of this study is to shed light on the mechanisms
involved in aragonite-to-calcite transformation in response to high temperatures exposure.
Mineralogical and structural changes in the shell of the marine gastropod Phorcus turbinatus areobserved by means of Confocal Raman Microscopy, Scanning Electron Microscopy and Atomic
Force Microscopy. The results show a different thermal behaviour among the two aragonitic shelllayers, which transform into calcite at different temperatures. Such a heterogeneous response islikely related to the different types of microstructures and organic content of the two shell
portions. Overall, our data suggest that carbonate structural properties might be an extremely
important factor to take into consideration when studying diagenetic alteration dynamics.

Session: Biomineralization

66

5th International Sclerochronology Conference, ISC 2019

Exploring illicia microchemistry: a new tool for fish age
determination?
Sílvia Pérez-Mayol1, Beatriz Morales-Nin1*, Audrey J. Geffen2, Roxanne
Duncan3, Deirdre Brophy3
1

IMEDEA CSIC/UIB, Miquel Marques 21, 07190 Esporles, Spain
Department of Life Sciences, Imperial College London, Imperial College Road, London SW7 2AZ, UK
3
Marine and Freshwater Research Centre, Galway Mayo Institute of Technology, Dublin rd, Galway, H91 T8NW,
Ireland2*presenting author: beatriz@imedea.uib-csic.es

The microchemical composition of calcified tissues of marine organisms is a well developed tool
to unravel life history events, assess migrations and determine stocks. Most studies in fish are
based on otoliths and more infrequently on scales and bones (vertebra, spines or fin rays). The
illicium is the most antero-dorsal spine present in fish of the genus Lophius, it appears as a long
filament movable in all directions that these predators use to attract other fish to their jaws. Illicia
are calcium phosphate structures, mainly composed of hydroxyapatite (Ca5(PO4)3(OH) and aprotein matrix, that are metabolically active and subject to elemental mobilization and resorption,
and are used, as otoliths, for age determination. They are the structure of choice for age
determination of Lophius piscatorus due to the lack of distinct bands in their otoliths that makes
them very difficult to interpret.
In this pilot study we develop the methodology to analyse illicia using laser ablation-inductively
coupled plasma-mass spectrometry (LA-ICPMS), a highly sensitive analytical technique that allows
a high spatial resolution. The aim is to validate seasonal trends in microchemistry and relate themto the visual growth marks usually employed in age determination using illicia.
For this purpose we used white anglerfish (L. piscatorus) collected in winter, spring, summer andautumn (2017/2018) at the Southern Celtic Seas and the Bay of Biscay. Lithium, Na, Mg, Al, P, K,
Ca, Mn, Fe, Zn, Sr, Ba and Pb were quantified by LA-ICPMS on the identified growth marks and on
a radial continuous line of 20 illicia transverse sections, and used to compare between fish
collected in each season. The evaluation of the data determines if there are annual cycles in
microchemistry that could be used to estimate age. Moreover, the comparison of the results
between the transects along the illicia radius and in the identified growth marks provide
supplementary information about the characteristics of illicia and anglerfish life history events.

Session: Growth, Bioenergetics and Ecosystems

67

5th International Sclerochronology Conference, ISC 2019

Anomalous 18O-depletions of Madeiran Glycymeris growthincrements – A new tool to trace meridional shifts of the
Azores Front
Alexandra Németh1,2*, Zoltán Kern1,2, Ronny Boch3
1

Isotope Climatology and Environmental Research Centre (ICER), MTA ATOMKI, Debrecen, Hungary
Institute for Geological and Geochemical Research, MTA Research Centre for Astronomy and Earth Sciences,
Budapest, Hungary
3Institute of Applied Geosciences, Graz University of Technology, Graz, Austria
2*presenting author: nemethalexandra89@gmail.com

Despite the positive results obtained using saltwater clam Glycymeris spp. forpalaeoenvironmental reconstructions in the extratropical North Atlantic domain, its potential has
not been investigated in the subtropical North Atlantic region. The aim of this study was toinvestigate cockles (G. vanhengtsumi) as archives for climate perturbations from the subtropicalregion by measuring the oxygen isotope compositions from the annual growth increments. The
shells’ habitat ranging from 150-160 m depth offshore Madeira is exposed to relatively minor
seasonal contrasts in terms of temperature compared to higher latitudes. The region itself,
however, is exposed to the highly dynamic system of the Azores Current and its associated front
on the north-eastern boundary of the North Atlantic Subtropical Gyre.The three analysed shells
were collected (one alive and two as sub-fossil specimens) near the Desertas Islands, Madeira in2014. They were selected from a set of synchronized increment series of a robust site chronology
for the 1950–2012 period which was used to explore shell growth responses to environmental
parameters in an earlier study. As the three increments series are overlapping in time, thecollected carbonate samples cover the period between ~1957 and 2010. Annual increments were
sampled at seasonal resolution (min. 3 max 7 sample points per increment) using a computercontrolled micromill device (ESI New Wave Research, Portland). Stable carbon (δ13C) and oxygen(δ18O) isotope compositions of the carbonate samples were analysed by an IRMS. Oxygen isotopic
ratios measured from the shells’ carbonate and regional seawater δ18O were used to calculate
water temperatures on a seasonal resolution based on isotope equilibrium relationships. The
results mostly coincided with the expected seasonal temperature range (17-19°C) of the shells
habitat, except from a few anomalously high temperature values inferred (20-23°C), e.g. for 19861988 and in the late 70’s. During these years, the modelled position of the Azores Front shifted
southward unexpectedly (~31° N) compared to its usual position situated between 33° and 35° N.
This relationship suggests that anomalous δ18O-depletions of the Madeiran cockle increments are
not necessarily connected to real water temperature anomalies as the upper layer of the watercolumn has prominently lower δ18O values north of the Azores Front than south of it.
Our results suggest that sclerochronological analysis of Glycymeris spp. shells combined with highresolution stable oxygen isotope measurements could be used to track regional changes of thissubtropical current system.

Session: Proxy Development: Challenges and Opportunities

685th International Sclerochronology Conference, ISC 2019

Evaluating Porites microatolls for climate reconstructions:
Records from French Polynesia
Nicholas Farley1*, Elias Samankassou1, Guillaume Antonioli1, Nadine Hallmann2,
Gilbert Camoin2, Anton Eisenhauer3, Claude Vella2, Glenn A. Milne4
1

University of Geneva, Rue des Maraîchers 13, CH-1205 Geneva, Switzerland
Aix-Marseille Université, CNRS, IRD, Collège de France, CEREGE, Europôle Méditerranéen de l'Arbois, BP80,
13545 Aix-en-Provence cedex 4, France
3
GEOMAR Helmholtz-Zentrum für Ozeanforschung, Wischhofstraße 1-3, 24148 Kiel, Germany
4
University of Ottawa, Department of Earth and Environmental Sciences, Ottawa, Ontario K1N 6N5, Canada
2*presenting author: nicholas.farley@unige.ch

Through a collaborative project we have a succession of Porites microatolls throughout the mid tolate Holocene. In order to carry out paleoclimate reconstructions we have first scrutinized how
suitable Porites microatolls are at recording sea-surface temperatures by comparing modern
microatolls against instrumental (MeteoFrance) and satellite temperature data.
Based on the classical Sr/Ca and δ18O, and additionally Sr-U (DeCarlos et al., 2015, 2016) and LiMg (Montagna et al., 2014), we tested sample material from Bora Bora and Maupiti in the present
study. We further measured the elemental ratios of Ba/Ca to monitor changes in environment andinvestigate possible vital effects. Congruent with the recent literature on massive Porites, theSr/Ca ratios of individual corals show offsets which can be attributed to vital effects. When we
combine three records, we can reconstruct the temperature record accurately with an r2 of 0.80
and producing a final calibration for French Polynesian Porites microatolls Sr/Ca = -0.0675(±0.004)
SST + 10.887(±0.059) which is coherent to massive Porites corals previously published (e.g.,
Cahyarini et al., 2008 with a gradient of -0.0663(±0,004) and r2=0.74. The δ18O record, althoughstill well correlated with temperature (r2 of 0.77) has a much larger range of values between therecords so is not nearly as precise. The Sr-U corrects to some extent for vital effects however it isthen not suitable for time series analysis. The Li/Mg data are currently being compiled andquantitively compared against the Sr/Ca record but so far qualitatively they do not seem to be aseffective as a composite of multiple Sr/Ca records.
The current results indicate that microatolls can be a valuable record of past sea-surface
temperatures, easily as good as massive Porites. Final conclusions on the reliability of the latest
geochemical paleothermometers will be available for our samples

Session: Climate and Oceans: Past, Present and Future69

5th International Sclerochronology Conference, ISC 2019

Microscale stable isotopic analytical system (MICAL3c)
reveals high-resolution temperature history of fish otoliths
Kozue Nishida1,2*, Tatsuya Sakamoto2,3, Tomoya Aono1,3, Saburo Sakai4, Toyoho
Ishimura1
1

National Institute of Technology, Ibaraki College, Japan,
The Japan Society for the Promotion of Science (JSPS), Japan
3
Atmosphere and Ocean Research Institute, The University of Tokyo, Japan
4
Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Japan
2*presenting author: nishida@gm.ibaraki-ct.ac.jp

Since the 1950’s, stable carbon and oxygen isotope (δ13C and δ18O) of biological carbonate havebeen used for paleoenvironmental and paleoecological studies, and, in particular, δ18O is a
powerful tool for estimating environmental history (such as temperature, seawater δ18O).
Recently, we have been developed the method of high resolution stable carbon and oxygenisotope analysis by using customized microscale isotopic analytical system (MICAL3c with
IsoPrime100: Ishimura et al. 2004, 2008). MICAL3c enabled us to determine δ13C and δ18O values
for small amounts of carbonate, as low as 0.2 μg, which is less than 1/100 of the amount requiredby conventional methods, with analytical precision less than 0.1‰. Recently, we have reported
micro-volume stable isotopic data by using MICAL3c system of various carbonate, such as the
single foraminiferal specimens (Ishimura et al., 2012; Takagi et al., 2015), the single grain of theinternational reference materials (Ishimura et al., 2008; Nishida and Ishimura, 2017) and fish
otoliths (Kitagawa et al., 2013; Sakamoto et al., 2017, 2018). In this study, we introduce our recent
studies using the microscale isotopic analytical system which is applicable for sclerochronology ofvarious calcifiers.
To track the movements of fish in open oceans is of great importance for efficient fisheries
management to understand population structures and the environmental cause of recruitment
variabilities, and, recently, fish otolith has been focused on for understanding of fish ecology.
Otolith δ18O is known to reflect ambient water temperature through fish growth; however, it has
been difficult to obtain time-series stable isotope data because of the limits of milling techniqueof small-sized specimens and carbonate weight for isotopic analysis. To solve these issues, we haveapplied our MICAL3c system in combination with the high precision micro-milling system(Geomill326, Izumo-web, Japan) for realizing high-resolution time-series stable isotope data of fish
otolith. By using this milling system, we can obtain about 40 samples from a 1 mm-length otolith,
and the milling line width is 10 to 50 μm. This resolution is close to the reported resolution ofSecondary Ion Mass Spectrometry analysis (e.g. Shiao et al., 2014). We will present our challenges
including the evaluation of the otolith-δ18O thermometer of Japanese sardine, Sardinops
melanostictus through the temperature-controlled culture experiment for rigorous temperature
calculation (Sakamoto et al., 2017), and the estimation of high-resolution migration history ofJapanese sardine in the North West Pacific by using microvolume isotope analysis and numericalsimulation (Sakamoto et al., 2018).

Session: Proxy Development: Challenges and Opportunities

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Drivers of synchrony among deep-water snappers
Joyce Ong1*, Corey Wakefield2, Malin Pinsky1, Stephen Newman2
1

Department of Ecology, Evolution and Natural Resources, Rutgers University, 14 College Farm Road, New
Brunswick, New Jersey 08901, USA
2
Western Australian Fisheries and Marine Research Laboratories, Department of Primary Industries andRegional Development, Government of Western Australia, PO Box 20, North Beach, WA, 6920, Australia*presenting author: joyce.ong.jl@rutgers.edu

Marine fisheries contribute significantly to food security, nutrition, employment and trade ofmany countries. Hence, the sustainability and vulnerability of marine fisheries is a critical concern,
especially given the increased risks related to climate changes and the potential for overfishing.
Synchrony of population fluctuations has become an important lens for understanding fisheries
because of its negative effects on the stability of aggregate properties such as total biomass
production and yield. In addition, synchrony points to major drivers of population dynamics suchas climate, trophic interactions or anthropogenic factors. Most fisheries studies detecting
synchrony from ecological timeseries data use correlation-based methods, however, thesemethods do not take non-stationarity, temporal autocorrelation, lags and timescale-specificchanges into account. Here, we use wavelet analysis, which can account for such issues, to detect
timescale-specific synchrony within populations of two deep-water snappers along the northwest
coast of Australia. We constructed otolith biochronologies from 113 fishes of the species
Pristipomoides zonatus and Lutjanus bohar. These timeseries spanned a 37 year series from 1970
to 2006. Population synchrony within and between species was investigated followed by an
examination of potential drivers of synchrony. Examples of potential drivers included strength ofthe major boundary current and several large-scale oceanographic processes such as the Pacific
Decadal Oscillation, Indian Ocean Dipole and ENSO. We identify the dominant timescales at which
synchrony occurs, time-specific changes in synchrony and the phase relationships (in-phase, phaselagged and anti-phase) between the population dynamics of these deep-water snappers andpotential drivers of synchrony. Preliminary analyses reveal that both species are not responding
synchronously to each other. Lutjanus bohar has a dominant timescale pattern of 6-8 years andseems to be related to the Pacific Decadal Oscillation and the Indian Ocean Dipole. Pristipomoides
zonatus has a shorter dominant timescale pattern of around 4 years and is strongly related to thestrength of the major boundary current and ENSO. Detecting synchrony and lags, both within
populations and between potential drivers, is helpful for understanding how to mitigate andprepare for future populations responses to climate and anthropogenic changes.

Session: Fisheries Ecology and Management715th International Sclerochronology Conference, ISC 2019

Biomineralization in Spirula spirula: first proteomic data andnew microstructural inputs
Morgane Oudot1*, René Hoffmann2, Emmanuel Fara1, Pascal Neige1, FrédéricMarin1
1

Biogéosciences, UMR CNRS 6282, Université Bourgogne Franche-Comté, 6 boulevard Gabriel, 21000, Dijon,
France2
Department of Earth Sciences, Institute of Geology, Mineralogy, and Geophysics, Branch Paleontology, RuhrUniversität Bochum, Universitätsstrasse 150, 44801 Bochum, Germany*presenting author: morgane.oudot@u-bourgogne.fr

The ram’s horn squid Spirula spirula (Linné 1758) is an enigmatic small-sized mesopelagic
cephalopod (Coleoidea, Decabrachia) with a specific anatomy, made of a mosaic of plesiomorphic
characters and synapomorphies, and resulting in a predominantly head-down swimming position.
In contrast to the highly abundant shells that can be collected on the beaches of the Atlantic,
Indian and west Pacific Oceans, the life habits of Spirula remains poorly known. A few studies haveinvestigated the shell microstructure but the shell biochemistry has never been examined so far.
Yet, considering the enigmatic anatomy and the differing microstructure of the Spirula shells, itappears quite interesting to characterize the organic matrix responsible for the shell formationand compare it with other cephalopods (such as cuttlefishes or nautiloids), or other shell-bearing
marine molluscs. Accordingly, this study aims at bringing the first biochemical characterisation of
the spirulid organic matrix and novel microstructural inputs, and at confronting thebiochemical/proteomic data with the morphological one. Our main results show that the organic
matrix is sugar-rich and protein-rich, with macromolecules ranging from low to high molecularweights. Nevertheless, low molecular weights proteins may be more abundant. We also noticed
the presence of a putative calcium-binding component around 17 kDa. The saccharides of theorganic matrix are predominantly represented by mannose, galactose and acetylglucosamine. The
first proteomic analyses performed on diverse shell extracts of S. spirula identified numerous
peptides. However, few of them actually match with already known mollusc skeletal proteins,suggesting that the shell matrix of the ram’s horn squid is quite different from that of other shellbearing molluscs studied so far. In parallel, SEM observations reveal some structures rarely
described in the literature: at the junction of the septa with the shell wall, the lamello-fibrillar
structure of the septa is inserted between two sub-layers of the internal microstructure of thewall, in the form of a bevel. Besides illustrating the complexity of S. spirula's shell microstructures,
our study provides the first exhaustive characterization of the shell organic matrix of this species.

Session: Biomineralization72

5th International Sclerochronology Conference, ISC 2019

Separating seasonality in temperature and the oxygenisotopic composition of water: Sub-annual clumped isotope
analysis of gastropods
Sierra V. Petersen1*, Jade Z. Zhang1, Serena R. Scholz1, Rebecca C. Heaman1,
Niels J. de Winter2, Johan Vellekoop2,3
1

University of Michigan, Ann Arbor, Michigan, USA
AMGC, Vrije Universiteit Brussel, Belgium
3
KU Leuven, Belgium
2*presenting author: sierravp@umich.edu

High-resolution oxygen isotope records from fossil marine mollusks are an important archive of
past sub-annual climate change. However, the oxygen isotopic composition of shell carbonate is
influenced by both growth temperature and changes in the oxygen isotopic composition of local
waters (d18Owater). Mollusk species targeted for sclerochronology studies commonly live in coastal
regions where changes in d18Owater are likely occurring, which would interfere with interpreted
temperature seasonality in unquantified constructive or destructive ways. In contrast, theclumped isotope paleothermometer (D47), based on the ordering of heavy isotopes of both carbon
and oxygen within the carbonate lattice, can determine growth temperature independent of
d18Owater. When combined with simultaneously-measured d18O of carbonate, can additionallydetermine past d18Owater values themselves. It has been difficult to apply this powerful new
paleothermometer at sub-annual scales due to large sample size requirements. Althoughtechnological advances continue to reduce sample sizes, typical sclerochronological micromilling
methods are still generally out of reach of the clumped isotope proxy, or require pooling of manyadjacent samples. Large, fast-growing marine gastropod species produce enough shell material
per year to easily allow for sub-annual sampling for D47. However, published clumped isotope
calibration efforts targeting any marine gastropod species (i.e. modern specimens collected fromknown environments) are limited to five individual shells representing only two species (Cittarium
pica and Conus ermineus), each sampled at one point per shell.
In this study, we expand this small marine gastropod calibration dataset with the addition of many
more species (Campanile symbolicum, Busycon carica, Busycon (Sinistrofulgur) sinistrum, andothers) from a variety of modern localities and apply both bulk and sub-annual isotopic samplingstrategies. We use high-resolution d18O analyses to define seasonal structure and growth rate,then take larger samples at sub-annually spaced intervals for D47. We compare D47-derived
temperature and d18Owatervalues to known environmental conditions to determine whether these
species reliably record climate conditions or whether 'vital effects' cause offsets fromthe expected D47-Temperature relationship founded on analysis of synthetic carbonates. We
investigate sub-annual changes in d18Owater and estimate the impact observed changes would haveon d18O-based paleoclimate reconstructions if not considered. Overall, this study serves todemonstrate the potential of a combined d18O-D47measurement scheme to eliminate potential
biases caused by changing d18Owater and reveal more accurate sub-annual paleoclimate
information.

Session: Proxy Development: Challenges and Opportunities
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5th International Sclerochronology Conference, ISC 2019

Coupling individual natural tracers to assess the connectivity
within a flatfish metapopulation
Marine Randon1*, Le Pape Olivier1, Bruno Ernande2, Kélig Mahé2, Filip
Volckaert3, Eric Petit1, Gilles Lassalle1, Thomas Le Berre1, Nathan Martin1, Elodie
Réveillac1
1

ESE, Ecology and Ecosystem Health, Agrocampus Ouest, INRA, 35042 Rennes, France
Fisheries Laboratory, IFREMER, 150 Quai Gambetta, BP 699, 62321, Boulogne-sur-Mer, France
3
Laboratory of Biodiversity and Evolutionary Genomics, Charles Deberiotstraat 32, box 2439, 3000 Leuven,
Belgium
2*presenting author: marine.randon@agrocampus-ouest.fr

In marine exploited populations, precise understanding of population structure and connectivity
is required to ensure sustainable fisheries. The common sole (Solea solea) of the Eastern English
Channel (EEC) stock is currently assessed and managed as a single and homogeneous populationand has been overexploited over the past decade. The existence of three subpopulations (withdifferent levels of exploitation by fisheries) has been recently suggested but has not been deeply
investigated so far. Whereas the connectivity induced by early life stages was assessed as low
inside the EEC stock, sub-adult and adult mixing between putative subunits remains unknown.
Here, we hypothesized that the common sole of the EEC stock presents a metapopulation
structure of three sub-populations. We assessed both genetic and demographic connectivity
within the common sole metapopulation of the EEC stock by analyzing, on the same adultindividuals, three complementary natural tracers: otolith microchemistry, otolith morphometry
and genetic markers. First, we assessed demographic connectivity between the juvenile and adultstages by introducing the otolith composition in trace elements into a Bayesian model to assign
adults to their nurseries of origin. Specifically, we implemented an atlas of nurseries otolithcompositions based on a reference data set comprised of juvenile individuals. Comparing adultotolith composition with the juvenile signatures allowed the allocation of adults to their nurseriesof origin. In parallel, we investigated, on the same adult individuals, genetic connectivity andpopulation structure using up to date genetic markers (Single Nucleotide Polymorphism from RAD
sequencing). Also, we tested for spatial segregation of sub-populations using the adults’ otolithshape (elliptical Fourier descriptors) as integrative tracer of life history. Finally, we compared anddiscussed the synergy and discrepancies between individual tracers. Otolith microchemistryindicated that a large part of adults were assigned to a nursery close to the spawning grounds
where they were sampled, which means that adults mainly reproduced in a local sub-population,
thus supporting a metapopulation functioning. Genetic assignments and otolith shape analyses
also suggested a metapopulation structure and especially highlighted the isolation of a subpopulation located in the South West from the rest of the EEC. Our findings support the hypothesisof a metapopulation structure of three sub-populations with relatively low connectivity andisolation of a southwestern subunit. Congruence and complementarity between otolith
microchemistry, otolith shape and genetic analyses were found and highlighted the interest of aholistic approach in connectivity studies.

Session: Fisheries Ecology and Management74

5th International Sclerochronology Conference, ISC 2019

Influence of El Niño Southern Oscillation events on otolith
growth and chemical chronologies in dusky grouper
Patrick Reis-Santos1,2*, Mario V. Condini3, Alexandre Garcia4, Cristiano Q.
Albuquerque3, Bronwyn Gillanders2, Susanne E. Tanner1
1

MARE — Marine and Environmental Sciences Centre, Faculdade de Ciências, Universidade de Lisboa, 1749-016
Campo Grande, Lisboa, Portugal
2Southern Seas Ecology Laboratories, School of Biological Sciences, The University of Adelaide, SA 5005,
Australia
3
Departamento de Ciências Animais, Universidade Federal Rural do Semi-Árido, CEP: 59625-900, Mossoró, RN,
Brasil4
Laboratório de Ictiologia, Instituto de Oceanografia, Universidade Federal de Rio Grande, Av. Itália Km 08,
Carreiros, CEP: 96.201-900, Rio Grande, RS, Brasil*presenting author: pnsantos@fc.ul.pt

Dusky grouper Epinephelus marginatus is the only large Epinephelidae species commonly foundalong subtropical latitudes, and is listed as ‘Endangered’ (IUCN Red List) due to a combination of
overfishing and complex life history strategy (slow growth rate, late maturation, aggregative
spawning behavior and sequential hermaphroditism). Here we develop otolith growth andchemical chronologies spanning a 30-year period for dusky grouper collected in the coastal region
adjacent to the Patos Lagoon - a major estuarine system in the Southwest Atlantic and one of themost productive fishing areas in Brazil. In this region, variations in the El Nino Southern Oscillation(ENSO) are renowned for modifying rainfall and estuarine biogeochemical cycles, and such
dynamism in environmental conditions likely influences individual fish growth. Therefore, we used
increasingly complex mixed models to partition intrinsic and extrinsic factors (including SST,
salinity, chlorophyll a, multivariate ENSO index, prey availability), evaluate their relative
importance to individual growth and otolith chemical composition, as well as to identify climateor environment-driven variations, namely how cold (La Niña) and warm (El Niño) episodes of ENSO
influence grouper population dynamics. Ultimately, understanding how local and regional
environmental variability drive grouper population productivity is key for management andconservation of this endangered species.

Session: Fisheries Ecology and Management75

5th International Sclerochronology Conference, ISC 2019

Northern Hemisphere ocean atmosphere interactions overthe last 500 years
David Reynolds1*, Bryan Black1, Ian Hall2, Freya Garry3, Paul Halloran3, James
Scourse4
1

Laboratory of Tree Ring Research, University of Arizona, Bryant Bannister Tree Ring Building, 1215 E Lowell St,
Tucson, AZ, 85721, USA
2
School of Earth and Ocean Science, Cardiff University, Main Building, Park Place, Cardiff, CG10 3AT, UK
3
School of Geography, College of Life and Environmental Science, University of Exeter, North Park Road, Exeter,EX4 4QE, UK
4
Centre for Geography and Environmental Science, College of Life and Environmental Science, University of
Exeter, Penryn Campus, Treliever Road, Penryn, Cornwall, TR10 9FE, UK*presenting author: davidreynolds@email.arizona.edu

Pre-industrial Northern Hemisphere climate variability is driven by the interplay between external
climate forcings (solar variability and volcanic aerosols) and internal mechanisms, such asatmospheric and oceanic feedbacks. Over the last 500 years the Northern Hemispheretransitioned from the relatively cold interval of the Little Ice Age into the industrial era
characterised by the modern anthropogenic warming. These intervals are also characterised bysignificant variability in total solar irradiance, volcanic aerosols and greenhouse gases. Hitherto
the lack of absolutely-dated marine reconstructions that extend over this period has precluded
the investigation of the role the oceans play in mediating Northern Hemisphere climate variability.
We utilise a hemispheric suite of absolutely dated sclerochronologies and dendrochronologies toinvestigate the mechanisms that drive inter-annual to centennial scale Northern Hemisphericclimate variability over the last 500 years. The absolutely dated nature of the records facilitates
the identification of coherent patterns of variability across large spatial scales on inter-annual tomulti-centennial timescales. These analyses suggest there is significant coherence between North
Atlantic Ocean and North Pacific Ocean variability over the last 500 years mediated by atmosphericcirculation patterns (Polar Jet stream, Pacific North America Pattern [PNA] and the North Atlantic
Oscillation [NAO]). Comparison of the spatial network with external forcing timeseries highlightsthat solar variability and explosive volcanic eruptions play a significant role in driving both theoceans and atmosphere. These analyses highlight the power of integrating sclerochronology anddendrochronology archives to reconstruct coupled ocean-atmosphere system dynamics, external
forcings, and internal mechanisms at a hemispheric scale.

Session: Climate and Oceans: Past, Present and Future76

5th International Sclerochronology Conference, ISC 2019

Hindcasting for forecasting. Disentangling the impact ofenvironment and fishing in Flemish Cap Atlantic cod
dynamics
Raquel Ruiz-Díaz1*, Rosario Domínguez-Petit2, Fran Saborido-Rey3
1

University of Gent, Marine Biology Research Group, 9000 Gent, Belgium
Spanish Oceanographic Institute, (IEO), 36390 Vigo, Spain
3
Marine Research Institute, (IIM-CSIC), 36208 Vigo, Spain
2*presenting author: raquel.ruiz103@gmail.com

The Flemish Cap (FC) Atlantic cod (Gadus morhua) population experienced a sharp decline that
ended up with the collapse of the stock by mid 1990s and, as consequence, the stock was on
fishing moratorium from 1999 to 2009. The goal of this study is to ascertain the environmental
variables that have influenced growth in a long time series that includes several decades ofimportant shifts in environmental conditions and fishing regime. In this study, sclerochronology isapplied to develop a multidecadal growth chronology from the increment widths of Atlantic cod
otoliths. Cod samples were collected in the Flemish Cap (FC), a seamount located in the Northwest
Atlantic (NAFO division 3M) at 200 m depths. A scientific survey is carried out by the Institute ofMarine Research and the Spanish Institute of Oceanography in this area since 1988. Otoliths are
selected base in the year of capture and the age of the individuals (+10 years). Otoliths are
sectioned, polished and mounted on resin. High resolution digital pictures of the section are taking
with the Leica stereomicroscopy M205 C at the highest magnification. Annuli are measured by thesoftware Fiji with the plugin ObjectiveJ from transversal section of aged otoliths. Finally, total
length and width as well as growth increments are measured. These measures of growthincrement are crossdated with COFECHA software. The detrended series are averaged withrespect to calendar year and a master biochronology is generated with the ARTSAN software. The
quality of the chronology is quantified using the Expressed Population Signal (EPS) statistic. Finally,
General Linear and Additive Mixed Models (GLMM and GAMM) are used to relate population
growth variability with indexes of exploitation, food availability (prey abundance index andcondition), climate (NAO and bottom temperature) and denso-dependency (cod abundance andcohort effect). Based on these results, growth trends could be[r1] forecasted under different
climatic scenarios to assess the potential impact of climate change on cod growth performanceand hence in productivity at mid and long term.

Session: Fisheries Ecology and Management77

5th International Sclerochronology Conference, ISC 2019

The “jewel of Mediterranean” Spondylus gaederopus:
insights into the biomineralization through biomolecularanalysis
Jorune Sakalauskaite1,2*, Beatrice Demarchi1, Frédéric Marin2
1
2

Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
UMR CNRS 6282 Biogéosciences, University of Burgundy-Franche-Comté, Dijon, France*presenting author: jorune.sakalauskaite@unito.it

Mollusc shells are one of the most fascinating systems for studying the fundamental processes of
biomineralization. Despite the great attention that this field has attracted over the years, ourknowledge on the mechanisms controlling biomineralization is still limited. This is due to thediversity of shell structural architectures and the size of the phylum. In-depth analysis is usually
carried out on model systems, hence the amount of information available for non-model systems,
especially with regard to the skeletal matrix, is even more scarce.
The thorny oyster Spondylus gaederopus is such an example. Considered as “the jewel of
Mediterranean”, it was used in rare occasions as climate archive but not for biomineralization
purpose, in spite of its peculiar evolution: on the basis of morphological arguments, spondylids
are supposed to have diverged from a pectinid ancestor in the middle Jurassic. But molecular
genetics suggests that the spondylid clade is rather a sister group of pectinids. This evolutionary
question is intriguing because Pectinidae shells are fully foliated (calcitic) whereas Spondylus ismostly crossed-lamellar (aragonitic). Even though this microstructure is the most common among
bivalves, very few studies have targeted the biomineralizing organic matrices of these shells.
We aim to get a deeper insight into the formation of Spondylus shells, which would extend ourknowledge on the mechanisms of biomineralization for “non-model” systems. Approaching thisfrom a biomolecular angle, we focus on studying the organic shell matrix and compare our new
molecular data with closely related taxa, i.e., Pectinidae and Ostreidae. We present preliminary
data that reveal the peculiarities of the “biomolecular toolkit” controlling Spondylus shellbiomineralization: this is one of the first studies attempting to probe the whole set of biomolecules(proteins, sugars, lipids and pigments) occluded in the shell skeleton. We discuss possible methods
for “big data” analysis and interpretation, given the paucity of comparative ‘omics datasets fornon model system. Our work sheds light on the complexity and rapid evolution of molluscan
skeletal matrices.
Finally, our work emphasizes an important question for the future: what drives the selection ofmodel organisms for biomineralization studies? Many studies have focused on commercially
important species. Our starting point is cultural: Spondylus has been an iconic shell since
Prehistory, and the presence of Spondylus ornaments can be used by archaeologists as an effective“tracker” for the movements and cross-cultural interactions of prehistoric communities. Our
biomolecular data will contribute to important archaeological projects.

Session: Biomineralization78

5th International Sclerochronology Conference, ISC 2019

Assessing geochemical seawater temperature proxies in the
deep sea bivalve Acesta excavata
Nicolai Schleinkofer1*, Jacek Raddatz1, Max Wisshak2, Axel Gerdes1, Jens
Fiebig1, Sascha Flögel3, Sebastian Streng1, Alexander Wacholz1, Silke Voigt1
1

Goethe University Frankfurt, Institute of Geosciences, Altenhöferallee 1, 60438 Frankfurt am Main, Germany
Senckenberg am Meer, Marine Research Department, Südstrand 40, 26382 Wilhelmshaven, Germany
3
GEOMAR Helmholtz Zentrum für Ozeanforschung Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany
2*presenting author: nicolai.schleinkofer@live.com

Cold-water coral reef communities provide a valuable source of proxy material for intermediatewater-depths. Unfortunately, strong vital effects and difficult growth patterns makeenvironmental reconstructions on cold-water corals, like Lophelia pertusa, rather difficult.
Organisms that inhabit the same habitat, such as the bivalve Acesta excavata could provide a
proxy-source which is less affected by vital effects and exhibits easier growth patterns.
Here we present solution based ICP-OES elemental ratios (Mg/Ca, Sr/Ca, Li/Mg, Mn/Ca, Fe/Ca)and stable isotope (δ18O & δ13C) measurements on A. excavata from two Norwegian cold-watercoral reefs (Sula & Nordleksa). Environmental parameters for proxy calibration are provided bythree landers that were deployed in close proximity to the observed reefs over the period of 13
months.
Our results reveal a significant correlation between Mg/Ca ratio and temperature in the high-Mg
calcite of A. excavata with a very high sensitivity that has not been observed so far in any othermarine carbonate or inorganic calcite. The calculated temperatures deviate from the in-situ
measured temperatures by a maximum of 0.5°C. Mg/Ca ratios in A. excavata therefore holds
promise to serve as a temperature proxy for intermediate water mass reconstructions withrelatively low variations. Furthermore, Li/Mg, measured by LA-ICP-MS, and Mg/Sr ratios also showpromising results as temperature proxies, by reducing the temperature deviations between
different specimens that are visible when using Mg/Ca ratios. This is presumably caused by similarvital effects on Mg/Ca, Sr/Ca and Li/Ca ratios (e.g., changes in the rate of skeletogenesis, nutrient
availability, etc.) which are minimized by using the elemental ratios in combination.
The δ18O ratio appears to be only partly controlled by temperature, but reveals a similar seasonal
cyclicity as the Mg/Ca ratio. The calculated temperatures however deviate by up to 2°C from thein-situ and the Mg/Ca temperatures. We propose that this is caused by kinetic effects that are due
to rapid calcification or changes in the hydrology either caused by freshwater influence orascending/descending water masses with concomitant changes of the ambient water δ18O signal.
Additionally, the high magnesium content in the skeleton could also cause increasing δ18O-values
which would lead to an underestimation of calculated temperatures.

Session: Proxy Development: Challenges and Opportunities

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5th International Sclerochronology Conference, ISC 2019

Brachiopods – faithful recorders of ocean properties?
Bernd R. Schöne1*, Eric O. Walliser1, Carsten Lüter2
1

Institute of Geosciences, University of Mainz, Joh.-J.-Becher-Weg 21, 55128 Mainz, Germany
Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43,10115 Berlin, Germany
2*presenting author: schoeneb@uni-mainz.de

Phanerozoic trends of ocean temperature were largely estimated from brachiopods. Respective
studies were triggered by Lowenstam (1961) according to which brachiopod shells preserve welland form in equilibrium with δ18Owater. However, this long-standing view was rivaled in the mid1990s demonstrating that species-specific isotopic disequilibrium occurs and certain shell portions
are affected by vital/kinetic effects. Auclair et al. (2003) and Yamamoto et al. (2011) also identified
growth rate-related isotopic offsets from expected thermodynamic equilibrium as well as
ontogenetic changes in modern cold-water terebratulids. Here, we followed in the footsteps ofthese authors and tested if the same applies to another modern, live-collected terebratulid,
Neothyris lenticularis from Chatham Rise (134 m water depth), New Zealand. Data of fossil atrypids(Devonian) and rhynchonellids and terebratulids (Cretaceous) were then compared to Veizer’s
isotope compilation. We also tested a variety of different illumination techniques and contrasting
methods in conjunction with polished, stained and etched cross-sections to identify shell growth
patterns in modern brachiopods. Findings on the latter were compared to concepts reported by
Ye et al. (2018).
Serial sampling from the posterior to the anterior margin was completed in the outer secondary
shell layer. Results of the modern brachiopod were contrasted to δ18Oshell time-series of a coeval
bivalve mollusk, Glycymeris sp., collected at the same locality. Whereas the glycymerid
δ18Oshell data fluctuated in a narrow range of +1.58 to +2.45 ‰ which closely reflects the seasonal
water temperature range (8-10°C), the δ18Oshell of N. lenticularis were more than -2.00 ‰ offset(considering the different isotopic fractionation between glycymerid aragonite and low-Mg calciteof the brachiopod) and showed seasonal fluctuations with an amplitude of up to 2.59 ‰ as wellas an ontogenetic shift to higher δ18Oshell (lifespan ca. 10 years). During the first six years of growth,δ18Oshell fluctuated around ca. -0.50 to -1.00 ‰ followed by a gradual increase. However, oxygenisotopic equilibrium was never reached, i.e., even the highest δ18Oshell values (likely representing
winter) were still ca. 0.70 ‰ more negative than expected. Following these findings, temperatures
reconstructed from δ18Oshell of N. lenticularis can at most provide a rough estimate of wintertemperatures, and only the most positive values determined at the anterior edge of old-grownspecimens are least affected by kinetic and vital effects. Although terebratulids are typically not
used for paleotemperature estimates, existing Paleozoic temperature estimates are most likely
far too high. Initial data from fossil brachiopods confirm this hypothesis.

Session: Climate and Oceans: Past, Present and Future80

5th International Sclerochronology Conference, ISC 2019

Atlantic herring recruitment in the North Sea for the past
455 years based on the δ13C from annual shell increments ofArctica islandica
Juan Estrella-Martínez1, Bernd Schöne2, Ruth Thurstan3, Elisa Capuzzo4, Paul
Butler5, James Scourse5*
1

School of Ocean Sciences, Bangor University, Bangor, Wales, UK
Institute of Geosciences, Johannes Gutenberg University, Mainz, Germany
3
Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK
4
Centre for Environment, Fisheries and Aquaculture Science (Cefas), Lowestoft, UK
5
Centre for Geography and Environmental Sciences, University of Exeter, Penryn, Cornwall, UK2*presenting author: j.scourse@exeter.ac.uk

Understanding the recruitment variability of the Atlantic herring (Clupea harengus) North Sea
stock remains a key objective of stock assessment and management. Although efforts have been
undertaken linking climatic and stock dynamic factors to herring recruitment, no major attempt
has been made to estimate recruitment levels before the 20th century. Here we present a novel
annually-resolved, absolutely dated herring recruitment reconstruction, derived from carbon
stable isotope geochemistry (δ13C) of Arctica islandica shell increments from the Fladen Ground(northern North Sea). Our age model is based on a standardised growth increment chronology
obtained from fourteen shells. Ten of these were micromilled at annual resolution for δ13C
analysis. Our results indicate that the anthropogenically-driven relative depletion of 13C, theoceanic Suess effect (oSE), became evident in the northern North Sea in the 1850s. We calculated
a regression line between the oSE-detrended δ13C results (δ13CṠ) and phytoplankton primary
production in the North Sea, which is modulated by the effect of the latter on the δ13C of theambient dissolved inorganic carbon. We used this regression to build an equation mediated by anutritional link to reconstruct herring recruitment using δ13CṠ. The reconstruction suggests that
there were five extended episodes of low recruitment levels before the 20th century. These results
are supported by measured recruitment estimates and historical fish catch and export
documentation. This work demonstrates that molluscan sclerochronological records cancontribute to the investigation of ecological baselines and ecosystem functioning impacted byanthropogenic activity with implications for conservation and stock management.

Session: Fisheries Ecology and Management815th International Sclerochronology Conference, ISC 2019

Ecological responses of coral reef under different seawaterconditions inferred from mid-Holocene coral reefs at thecentral Ryukyu Islands, Japan
Kohki Sowa1*, Chuki Hongo2, Saburo Sakai1, Kosei E Yamaguchi3,4
1

JAMSTEC, 2-15 Natsushima-cho, Yokosuka-city, Kanagawa, Japan
University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami-gun, Okinawa, Japan3
Toho University, 2-2-1 Miyama ,Funabashi-shi ,Chiba, Japan
4
NASA Astrobiology Institute2*presenting author: sowak@jamstec.go.jp

The Kuroshio Current provides favorable environmental conditions for the coral reef ecology of
the Ryukyu Islands, Japan, where one of the highest coral species diversities in the world is found.
Currently, coral reefs are threatened by both global and local environmental changes. To assist
with effective coral ecology restoration plans, data on coral species and cover and environmental
data on the “pre-industrial era” conditions are essential. However, most of the existing coral reefs
have been affected by global and local environmental stresses, as a result of which, data frommodern monitoring would not reflect conditions of the “pre-industrial era.” The Holocene uplifted coral reefs emerge around the Ryukyu Islands coastal area. Studies of the sediment coresshow that sea surface temperatures of the Kuroshio Current have been persistent during the past
7500 years. Therefore, an integrated analysis of coral geochemistry using coral skeletons andpaleontology of the up-lifted Holocene coral reef at the Ryukyu Islands would provide valuable
data on the “pre-industrial era” coral reef conditions. Previous studies have been limited to the
Kikai Island, situated along the higher latitudes of the Ryukyu Islands, whereas the current study
scrutinizes the central part of the Ryukyu Islands. We show an integrated analysis of coralgeochemistry and paleontology of up-lifted Holocene coral reefs at the central Ryukyu Islands,
Japan. The 14C age of the fossil Porites coral estimated to be 5400±140 cal. yr BP. The seasonal
δ18O of the fossil Porites coral (~26-year, N=1) averages -4.36‰, which is ~+0.54‰higher thanthat of the modern coral (~5-year, N=2). XRD analyses and SEM observation show goodpreservation of the fossil coral skeletons. The averaged extension rates of the fossil/modern coral
cores have been calculated at >6 mm/year, indicating a minor kinetic isotopic effect related toskeletal growth. Fossil and modern coral skeletal δ18O values imply that the Kuroshio Current was
saltier in the mid-Holocene than it is today. Despite higher salinity, the fossil coral species were nodifferent than those found in the modern coral reefs. Research results also show that coral
coverage in the Holocene was higher than that observed in the modern coral reefs (14.4% vs.
10.5%). Coral cover diminution has been likely caused by recent negative impacts of global andlocal environmental stress. We have further discussed the effects of reconstructed local-SST and
sediment loading/upwelling using coral skeletons.

Session: Paleoecology and Evolution82

5th International Sclerochronology Conference, ISC 2019

How do deep-sea fish respond to environmental change:
Patterns and drivers of growth variation among space, time
and taxonomy
Susanne E. Tanner1*, Eva Giacomello2, João Neves2, John R. Morrongiello3,
Patrick Reis-Santos1,4, Rita P. Vasconcelos1,5, Ana Rita Vieira1
1

MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências, Universidade de Lisboa, 1749-016
Lisboa, Portugal
2
IMAR/Okeanos/MARE, Rua Prof. Dr. Frederico Machado 4, 9901-862 Horta, Portugal
3
School of Biosciences, University of Melbourne, Victoria 3010, Australia
4Southern Seas Ecology Laboratories, School of Biological Sciences, The University of Adelaide, SA 5005,
Australia
5
IPMA – Instituto Português do Mar e Atmosfera, Rua Alfredo Magalhães Ramalho, 6, 1495-006 Lisboa,
Portugal*presenting author: setanner@fc.ul.pt

The deep ocean remains the least explored biome on Earth and is inhabited by many organismsthat are highly vulnerable to human pressures and environmental change due to their life histories
characterized by long lives, late reproduction and low fecundity. Here, we use growth as a proxy
to measure organisms’ response to environmental change as growth is sensitive to a range ofdrivers including temperature effects on physiology, changes in food webs and fishing intensity,
as well as playing a fundamental role in determining fitness. Growth rate information naturally
archived within otoliths of a set of deep-sea fish species (Helicolenus dactylopterus, Pontinus
kuhlii, Pagellus bogaraveo) is used to develop chronologies documenting growth variations in awide marine region (Iberian Atlantic coast and oceanic islands of Azores and Madeira). We use
among and within species mixed effects models capturing both intrinsic (e.g. age, sex, age at
capture, species) and extrinsic sources (e.g. temperature at depth, climatic indices, fishingpressure) of variation in growth to assess the relative importance of drivers as well as the temporaland spatial patterns in population productivity. These models are also used 1) to investigatetransferability of temporal patterns and drivers of growth variation between fish species in the
deep-sea; and 2) to evaluate spatial upscaling of identified patterns of growth variation and drivers
for individual species from 10s to 1000s of kms. The integrated assessment of growth variation
across species and over wide temporal and spatial extents provides a means to better understandhow human-induced and climate driven effects impact understudied systems, such as the deepsea.

Session: Fisheries Ecology and Management83

5th International Sclerochronology Conference, ISC 2019

Investigating scale trace element microchemistry as a tool to
track adult North Atlantic salmon populations
Elizabeth Tray1,3*, Quentin Crowley2, Niall O'Maoileidigh3, Deirdre Brophy1
1

Marine and Freshwater Research Centre, Galway Mayo Institute of Technology, Co. Galway H91 T8NW, Ireland
Trinity College Dublin, Geology, Dublin 2, Co. Dublin, Ireland
3
Marine Institute, Furnace, Co. Mayo F28 PF65, Ireland2*presenting author: Elizabeth.Tray@gmit.ie

Despite ongoing global conservation measures for north Atlantic salmon, the species has
experienced recent population declines. Marine habitat use of salmon is still widely unknown.
Non-invasive and robust methods are needed to monitor salmon marine habitat use on large
temporal and spatial scales. Microchemical analyses of scales and otoliths can provide insight into
the environmental history of migrating salmon. Scales are an advantageous sample type because
they can be easily and non-lethally obtained. Reconstruction of environmental histories fromanalyses of scale growth trajectories may however be confounded by metabolic re-working ofscale calcium after deposition. The mechanism controlling post-depositional chemical exchange infish scales is underexplored, and further investigation is needed to determine the extent ofcompromised material. In addition, many scale microchemistry studies report trace elements asratios (element: calcium), assuming calcium is constant through the hydroxyapatite (HAP). Thereis a lack of published data on salmon scale calcium variability within a single sample and between
individuals. Understanding HAP calcium variability is important when reporting elemental
concentrations, because small changes in calcium could greatly impact trace element ratio
values. Recently, advances in material science technologies have provided new (non-destructive)
methods that allow for more precise measurement of fish scale structure and composition. The
aims of the study were to: 1) use new tools to measure salmon scale HAP calcium variability andre-evaluate the significance of post-depositional exchange, 2) determine if trace element profiles
from adult salmon scales can be used to characterize feeding grounds inhabited by returning
migrants.
Scanning electron microscopy (SEM) and white light interferometry were used to characterize
scale HAP, and energy dispersive spectrometry (EDX) was used to measure scale calcium. Laser
ablation inductively coupled mass spectrometry (LA-ICP-MS) was used to investigate traceelements within salmon scale HAP. Scales were sampled (n=59) from salmon actively feeding fromthe Greenland fishery (marine), and from an Irish population of returning adults (river). Scale
growth marks were used to partition the freshwater (FW) and saltwater (SW) portions of the
microchemistry transect. Trace element profiles were compared between fish collected from thefeeding grounds and fish collected in the rivers on their return migration, to evaluate the extent
to which over-plating or resorption affects the feeding ground signature. In addition, traceelement data was analysed for variability between individuals, to determine if adult individuals inthe same habitat record similar trace element profiles.

Session: Fisheries Ecology and Management84

5th International Sclerochronology Conference, ISC 2019

Inferring movement tracks of individual baleen whales fromchemical records combined with coupled simulation models
Clive Trueman1*
1

Ocean and Earth Science, University of Southampton, UK*presenting author: trueman@noc.soton.ac.uk

Movement ecology has been revolutionised by the development of animal-based telemetry.
Smart tag deployment remains relatively expensive, however, and is not suitable for a wide rangeof organisms, and seldom records individual behaviour for periods greater than a year. Chemicalrecords contained in incrementally grown tissues provide the only retrospective records of animal
movements, but inferring location from tissue chemistry can be complex. Stable isotope
compositions are especially promising chemical proxies for location as the isotopic composition oftissues can be referred to spatial models of isotopic distribution (isoscapes).
Many marine organisms possess incrementally-grown tissues suitable for recording migration andmovement, but the isotopic composition of the marine environment is complex, temporally
dynamic and difficult to sample at sufficient spatio-temporal resolution. Consequently, few
studies have attempted to reconstruct marine animal movement paths based on chemical records
from incrementally-grown tissues.
In this talk I will outline how coupled simulation models can be used to infer individual animal
movement tracks from stable isotope records in incrementally grown tissues. I focus on baleen as
an incrementally grown tissue and stable carbon isotopes as my environmental tracer. I simulate
the isotopic composition of baleen plates expected under different migration trajectories bycoupling a simple agent-based movement model with a temporally-explicit global model of carbon
isotope composition of phytoplankton at 1 degree and monthly resolution. The simulation model
framework can then be used to generate multiple potential baleen isotope chronologies which
can then be compared to measured baleen data and most likely movement trajectories selected.
I will show how this approach has been used to infer probable movement trajectories in historicand modern blue whales in the Atlantic and Pacific Ocean, and show how the conceptual approach
can be extended to any animal-isotope system where a suitable predictive isoscape model isavailable.

Session: Growth, Bioenergetics and Ecosystems

85

5th International Sclerochronology Conference, ISC 2019

Linking sclerochronology to fish population dynamics
Peter van der Sleen1*, Bryan A. Black2
1
2

Department of Wetland Ecology, Karlsruhe Institute of Technology, 76437 Rastatt, Germany
Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA*presenting author: j.p.vandersleen@gmail.com

The population dynamics of fish are often characterized by conspicuous low-frequency variability
at multi-annual to multi-decadal scales. Understanding the origin of this variability is an urgent
need for fisheries management and allows to disentangle the effects of climate and humanactivity. Here, we propose that much of the low-frequency variability in fish populations can arise
from the “buffering” of higher-frequency climate signals through fish vital rates (e.g. growth,mortality and recruitment) and the species’ lifespan. The longer the lifespan, or the slower thevital rates, the greater the climate is “buffered”, which can be modeled by adding autocorrelation
to climate variables closely associated to fish biology. A key feature of higher autocorrelation isthe emergence of low-frequency variability, which would therefore be more likely in longer-lived
species. To test this hypothesis, we used an extensive, global-scale dataset on life-history traits offishes to demonstrate that the life span of fish is roughly related to trophic position andtemperature. We show how relatively simple models can be used to quantify low-frequency
variability in fish species from different trophic positions. Lastly, we added autocorrelation to
gridded global sea surface temperature data to modeled the level of “buffering” (autocorrelation)
we expected at each trophic level. In so doing, we quantify the patterns of low-frequency
variability we expect in fish populations, and identify regions where fish population may be more
prone to large-amplitude state transitions. These results provide context with which to distinguishpotential anthropogenic ecosystem change from “natural” population dynamics. Furthermore, weshow that sclerochronology can provide the information necessary to model and understand the
population dynamic of fish.

Session: Fisheries Ecology and Management865th International Sclerochronology Conference, ISC 2019

Relating patterns in annual growth of a Western Irish
European eel Anguilla anguilla Linnaeus, 1758 population tohabitat and climatic conditions
Louise Vaughan1,2*, Deirdre Brophy2, Russell Poole1, Ciar O'Toole1, Conor
Graham2, Niall Ó Maoiléidigh1, Elizabeth Tray1,2
12Marine Institute, Furnace, Newport, Co. Mayo, Ireland
Marine and Freshwater Research Centre, Galway-Mayo Institute of Technology, Galway, Ireland*presenting author: louise.vaughan@marine.ie

The European Eel (Anguilla anguilla) is a facultative catadromous species living in fresh, brackish
and coastal waters. Recruitment has been declining since the early 1980s at a European wide scale.
The collapse in recruitment and its catadromous lifestyle leaves the species vulnerable to climatic
influences. The Burrishoole catchment is situated on the North West Coast of Ireland. Lough
Feeagh and Lough Bunaveela are the two largest freshwater lakes in the catchment bothcontaining stocks of European Eel. Full trapping facilities have been in place between the Lough
Feeagh and the estuarine Lough Furnace since 1970 allowing for the sampling of downstream
migrating silver eels. Individual growth trajectories of silver eels collected on their outward
migration were examined using otoliths (1987, 1988, 2007, 2012, 2013 and 2017). Eels in the
Burrishoole catchment are particularly long lived with many eels achieving ages of 35 plus giving
growth trajectories spanning over 6 decades of growth. This study examined the use of mixed
effects models to account for both intrinsic and extrinsic effects on eel growth. The best fitting
model of intrinsic growth showed an age and sex dependent pattern of growth declining as thefish aged. This varied among individuals, year and cohort year. The models showed a difference ingrowth between male and female eels with females growing larger. Both sexes showed a decline
in growth with age.
Historically water temperatures in Irish systems were considered suboptimal for eel growth. Lakewater temperature data available from the 1960’s showed an increase in water temperatureacross all seasons particularly from the mid-1990’s onwards. Rising temperatures in Irish systems
could be expected to positively affect growth and survival of European eel. In this study the mean
temperature experienced by an individual fish over its lifetime was shown to have a positive effecton eel growth. Increasing water temperature in the Burrishoole system may have a positive effecton eel survival however further investigation is needed.
Future work will look to extend the modelling approach to other environmental variables andextreme events associated with climatic change. An in-depth examination of the microchemistryof otoliths will also be carried out to identify habitat usage of the eel population within the
Burrishoole catchment.

Session: Fisheries Ecology and Management87

5th International Sclerochronology Conference, ISC 2019sclero: an R package to measure growth patterns and alignsampling spots in chronologically deposited materials
Mikko Vihtakari1*
1

Institute of Marine Research, Fram Centre, Tromsø, Norway*presenting author: mikko.vihtakari@gmail.com

Visible growth lines can be used as time markers in chronologically deposited materials (i.e. proxyrecords) to reconstruct growth patterns of the material back through time. In general, proxyrecords do not deposit linearly through time and along the material complicating the dating of
geochemical signatures from proxy records, sampled using techniques such as milling, laser
burning, or particle bombarding. Consequently, to relate the samples to the time of deposition, it
is critical to identify the location of sampling spots in relation to the adjacent growth lines rather
than to measure a distance from a defined point along the proxy record. Further, sampling spots
introduce a time-averaging error, which varies depending on the area of the sampling spot,
curvature of growth lines and growth rate of the material.
An open-source package, sclero, was developed to solve the above-mentioned issues whenrelating the location of sampling spots to the time of deposition. The package is written in R, a
popular statistical programming language, and uses ImageJ for image analysis. This presentation
describes how to use the package to align sampling spots consistently to growth lines and how toestimate the time-averaging error in proxy records with complex inconsistently curved growthlines.

Session: Proxy Development: Challenges and Opportunities

88

5th International Sclerochronology Conference, ISC 2019

Temperature association and exposure of Icelandic cod(Gadus morhua) over the last 100 years
Gotje von Leesen1*, Ulysses Ninnemann2, Ásta Guðmundsdóttir3, Steven E.
Campana1
1

University of Iceland, Faculty of Life and Environmental Sciences, Sturlugata 7, 101 Reykjavik, Iceland
University of Bergen, Department of Earth Science and Bjerknes Centre for Climate Research, Allegaten 41,5007 Bergen, Norway
3
Marine and Freshwater Research Institute, Skúlagata 4, 101 Reykjavik, Iceland2*presenting author: gotjevonleesen@gmail.com

Increasing water temperatures are predicted around the globe with high amplitudes of warmingin Subarctic and Arctic regions where Atlantic cod (Gadus morhua) populations currently flourish.
To determine if cod will move or migrate to avoid increasing water temperatures, we havereconstructed oxygen isotope and temperature chronologies from otoliths of one of the largest
cod stocks in the world. Samples of the last 100 years were collected reflecting the environmental
conditions of the Icelandic waters. For δ18Ootolith analysis, individual annual growth incrementsfrom immature and mature stages were micromilled. Preliminary data show differences intemperature association and exposure between different life stages. Higher oxygen isotope values
were measured for mature cod suggesting that mature cod lives in deeper, colder water masses
relative to immature cod. Oxygen isotope values suggest that substantial temperature variations
occurred across the past century.

Session: Fisheries Ecology and Management89

5th International Sclerochronology Conference, ISC 2019

Paleoseasonality in the benthic environment of the Tethys
during the Late Cretaceous
Eric O. Walliser1*, Bernd R. Schöne11Institute of Geosciences, University of Mainz, Johann-Joachim-Becher-Weg 21, 55128 Mainz, Germany*presenting author: walliser@uni-mainz.de

Following the Cenomanian/Turonian event (OAE 2), the Late Cretaceous world experienced a timeinterval of significant global cooling, which mainly affected intermediate and deep waters intropical oceans. In the Tethyan realm, this climate transition coincides with a positive shift of ca.
1 ‰ in bulk carbonate δ18O values, which reflects a relative decline of ca. 4°C in bottom watertemperatures. However, precise information on the absolute water temperatures during this timeinterval is still lacking. Novel sclerochronological data (δ13C and δ18O) of a wellpreserved Inoceramussp. shell from the Turonian-Coniacian deposits of the Scaglia Rossa
Formation (Trento Plateau, Italy) suggest a mean annual temperature of ca. 15°C and seasonal
oscillations of ca. 1°C at the seafloor (ca. 150 m water depth) in the northwestern region of the
Tethys. According to the results, shell δ13C were positively correlated to shell δ18O values
suggesting that the process governing temperature fluctuations also affected food availability inthe water column. The reconstructed benthic temperatures, however, were consistently lower
than those estimated for the upper ocean layers in previous studies (21 to 35 °C). Such discrepancy
likely indicates a thermal decoupling of the two habitats which can possibly be explained by the
influence of deep and cold water masses on the benthic environment of the Trento Plateau likely
promoted by upwelling.

Session: Climate and Oceans: Past, Present and Future90

5th International Sclerochronology Conference, ISC 2019Local perspectives on ENSO mean states ~2300 B.P. andnow: δ¹⁸O reconstructions from the short-lived bivalves
Donax obesulus and Mesodesma donacium
Jacob Warner1*, Kristine L. DeLong1, David Chicoine1, C. Fred T. Andrus2,
Kaustubh Thirumalai3, Alan Wanamaker, Jr.4
1

Department of Geography and Anthropology, Louisiana State University, 227 Howe-Russell Geoscience
Complex, Baton Rouge, LA 70803, USA
2
Department of Geological Sciences, University of Alabama, 2003 Bevill Building, Tuscaloosa, AL 35487, USA
3
Department of Earth, Environmental, and Planetary Sciences, Brown University, Box 1846, 324 Brook St,
Providence, RI 02912, USA
4
Department of Geological & Atmospheric Sciences, Iowa State University, Ames, IA 50011, USA*presenting author: jwarn11@lsu.edu

Some areas lack long-lived organisms suitable for sclerochronological studies, creating a need fornovel archives. The presence of short-lived (<5 years) bivalves in archaeological contexts fills thisneed by allowing for the examination of “snapshots” of past climatic conditions rather than thecreation of continuous time series. Mesodesma donacium, a short-lived intertidal bivalve, is anestablished paleoclimate archive for coastal Peru. However, modern populations are functionallyextinct north of ~14°S, restricting the possibility for modern analog studies to southern Peru. M.
donacium is vulnerable to extreme El Niño events, which are increasingly common and strongly
impact the north coast of Peru. We use Donax obesulus, a short-lived surf clam, to compliment M.
donacium. D. obesulus populations survive the warmer sea surface temperatures (SSTs) of El Niño
events, though they are vulnerable to colder SSTs, especially those associated with extreme La
Niña events. The internal banding of D. obesulus is often difficult to distinguish, requiring the useof alternative age-determination methods alongside band counting to time-assign geochemical
data. Our method supplements band counting with a Von Bertalanffy growth curve for D. obesulus
determined by the Instituto del Mar del Peru from near our collection site adjusted to daily growthalong the axis of maximum height. We collected live D. obesulus from the Nepeña Valley,
department of Ancash, Peru in 2012 (La Niña), 2014 (ENSO-neutral), and 2016 (El Niño) for modern
analog studies. We compared forward models of δ¹⁸Oshell (a proxy for SST and δ¹⁸Owater) createdfrom SST and SSS measurements to δ¹⁸Oshell values obtained by subsampling modern shells thatwere time assigned by daily growth along the axis of maximum height. Our results indicate that D.
obesulus δ¹⁸Oshell captures on average 55±21% of modeled SST range (RMSE = 2.8°C), with seasonal
upwelling affecting the influence of δ¹⁸Owater on the overall signal. We sampled one M. donaciumand six D. obesulus from a Nepeña Valley archaeological site (Caylán) to test the two species ascomplimentary paleoclimate archives. M. donacium mean δ¹⁸Oshell is enriched ~0.8‰ compared
to preceding periods and ~1.1‰ compared to modern on the south coast of Peru, while Caylán D.
obesulus mean δ¹⁸Oshell is enriched ~0.7‰ compared to modern. Both shell species suggest La
Niña-like (~2–4 °C cooler) mean conditions or a shift in δ¹⁸Owater compared to modern ~2300 B.P.
These results suggest D. obesulus is a suitable compliment to M. donacium for paleoclimate
reconstruction.

Session: Climate and Oceans: Past, Present and Future91

5th International Sclerochronology Conference, ISC 2019

A 150 years Margritifera shell record reveals that summer
air temperature in northern Japan is linked to Atlantic
Multidecadal Oscillation
Tsuyoshi Watanabe1*, Mayumi Suzuki1, Kotaro Shirai2, Atsuko Yamazaki3
1

Faculty of Science, Hokkaido University, N10W8, Kita-ku, Sapporo 060-0810, Japan
Atmosphere and Ocean Research Institute The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba,277-8564 Japan
3
Faculty of Science, Kyushu University, 744 Motooka Nishiku, Fukuoka 819-0395 Japan
2*presenting author: nabe@sci.hokudai.ac.jp

We demonstrate the possible link of summer air temperature in northern Japan to Atlantic
multidecadal oscillation (AMO) using by sclerochronological and geochemical approaches on long
lived fresh water mussels Margritifera laevis, collected from Hokkaido, northern part of Japan. We
used the total 75 specimens from Shiribetsu and Teshio rivers in the side of Japan sea and from
Obetsu and Abira rivers in the side of Pacific Ocean, respectively. Observation of daily growth lines
and high-resolution analysis of trace elements (Sr/Ca, Mg/Ca, and Ba/Ca ratios) and stable oxygenand carbon isotopes suggest that distinct annual growth lines observed in each increments formed
in winter season. We calculated the standard growth index (SGI) for each river using annual growth
patterns in individual shell specimens and found that the SGI for Japan sea side was correlated to
winter snow volume and the SGI for Pacific side to summer air temperature. Here, we concentrate
to demonstrate SGI and geochemical records from Obestu river of Pacific side where the longest
lived shell of 150 years old was found. The sharp peaks of trace elements were observed in theshell increments of 1960. These indicate that the salt water inflow to the river induced by Tsunami
of Chili earthquake were recorded in corresponding shell deposition and confirm the fidelity ofage model of our shell records. A 150 years sclerochronological and geochemical records reveal
the positive correlation between AMO and SGI and negative between AMO and Ba/Ca ratio. We
discuss the possible climatic and environmental mechanisms such as the linkage between Pacificand Atlantic oceans through atmospheric interaction.

Session: Climate and Oceans: Past, Present and Future92

5th International Sclerochronology Conference, ISC 2019

Insights on AMOC dynamics over the last 300 years using
multiple geochemical proxies from an Arctica islandica
record in the western North Atlantic
Nina M. Whitney1*, Alan D. Wanamaker1, Beverly J. Johnson2, Caroline
Ummenhofer3, Shelly M. Griffin1, Erin Lower-Spies1, Karl J. Kreutz4, Philip T.
Dostie2, Katherine Luzier1, Douglas S. Introne4
1

Department of Geological and Atmospheric Sciences, Iowa State University, 2237 Osborn Drive, Ames, Iowa,
50011, USA
2
Geology, Bates College, 44 Campus Avenue, Lewiston Maine, 04240, USA
3
Woods Hole Oceanographic Institution, 86 Water Street, Woods Hole, Massachusetts, 02543, USA
4
School of Earth and Climate Sciences, University of Maine, 5790 Bryand Global Sciences Center, Orono, Maine,
04469, USA*presenting author: nwhitney@iastate.edu

Several recent studies, including both modeling and paleoceanography studies, have suggested
that the Atlantic Meridional Overturning Circulation (AMOC) has weakened in recent years as aresult of an anthropogenic freshening of the northern North Atlantic. However, there is no current
consensus on the timing of this weakening and the extent to which it is exceptional. More highresolution, absolutely dated paleoceanography records from locations strongly influenced by
AMOC variability are therefore necessary in order to help put recent changes in AMOC strength
into a broader context.
The Gulf of Maine, a semi-enclosed sea on the east coast of North America, is one such location
thought to be influenced by the AMOC. The Gulf of Maine hydrographic properties are affectedby changes in AMOC strength via the AMOC’s influence on the position of the Gulf Stream relative
to the entrance to the Gulf of Maine. These shifts in current position impact the composition ofwaters entering the Gulf of Maine and therefore can be recorded by geochemical proxies.
Here we present three different water mass proxies measured from Arctica islandica shells
collected near Seguin Island in the western Gulf of Maine and crossdated into a chronology that
extends back to 1762. Shell carbonate was sampled to obtain a decadally resolved radiocarbon
reservoir age record and an annually resolved oxygen isotope record. Shell periostracum was
sampled to obtain a decadally resolved nitrogen isotope record.
All three water mass proxies indicate more Gulf Stream derived waters entering the Gulf of Maine
recently, suggesting a weakening AMOC in agreement with other recently publishedpaleoceanography records. Proxies presented in this study suggest that this weakening beganaround the beginning of the 20th century but that, unlike conclusions drawn by other studies, thisweakening is not anomalous over the last 250 years as AMOC also appears to have been weak atthe end of the Little Ice Age.
This multi-proxy approach derived from a shell-based record therefore contributes a highresolution, absolutely dated reconstruction to the current understanding of how the AMOC has
behaved in the last several hundred years. Given the complexity of the AMOC system, no one
paleoceanography reconstruction can be expected to fully capture how the AMOC has changed
over this time period. However, by developing multiple records such as this one from locations
throughout the North Atlantic, a better understanding of past AMOC behavior and potential futurechanges can be gained.
Session: Climate and Oceans: Past, Present and Future93

5th International Sclerochronology Conference, ISC 2019

Seasonal patterns in shell gape activity of Arctica islandica
Rob Witbaard1*, Michael Carroll2, Irene Ballesta-Artero3
1

NIOZ; Netherlands Institute for Sea Research and Utrecht University, Department of Estuarine and Delta
Systems, PO Box 140, 4400 AC Yerseke, The Netherlands
2
Akvaplan-niva, FRAM-High North Centre for Climate and the Environment, 9296 Tromsø, Norway
3
NIOZ; Netherlands Institute for Sea Research and Utrecht University, Department of Coastal Systems, PO Box
59, 1790 AB Den Burg, Texel, The Netherlands*presenting author: rob.witbaard@nioz.nl

Arctica islandica (bivalvia) has a prominent role in the study of past ocean climate. Shell growth
patterns as well as the geochemical composition of the shell are used to reconstruct pasttemperatures and study the interaction between atmospheric and oceanic climate. In thisapproach, the bivalve biology is in most cases approached as a black box. There is insufficientknowledge on the behavior of these animals despite this information being crucially important tounderstand how and what aspects of the environmental signal is actually recorded in its shell.
Between February 2014 and September 2018 we deployed a lander frame in a shallow Arctic bay
in northern Norway. This lander was equipped with an array of self-logging instruments, among
which were 2 so-called valve gape recorders. With the latter the shell gape activity of 16 animals
was monitored at a time resolution of one minute over more than 4 years.
Analyses of these data showed that there are marked seasonal patterns in activity, i.e. wide open
valves in spring and summer and closed valves in winter. PCA analyses of this time series
corroborated the dominant relationship between valve gape and the concentration of Chlorophyll
previously observed over a shorter (19 month) interval. Temperature however, has a minor rolein the gaping activity patterns.
Comparison of the seasonal activity cycles showed that there are significant differences in thetiming and duration of valve gape among years. For example, at a valve gape threshold of 50%,
the difference in length of the active period between years is as long as 8 weeks. This suggeststhat the duration of the active period in this shallow arctic bay is variable among years and, might
partially control the observed inter-annual differences in shell growth observed in this species.

Session: Environmental Biomonitoring & Entrepreneurship94

5th International Sclerochronology Conference, ISC 2019

Linkage between climate condition and coral reefdevelopment on Holocene uplifted terraces in Kikai Island,
Japan
Atsuko Yamazaki1,2,3*, Wataru Kobayashi3, Kevin Garas3, Tsuyoshi Watanabe2,3
1

Faculty of Science, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, Japan
KIKAI institute for Coral Reef Sciences, Shiomichi 1508, Kikai-town, Kagoshima, Japan
3
Faculty of Science, Hokkaido University, N10W8, Kita-ku, Sapporo, Japan
2*presenting author: yamazakiatsuko@geo.kyushu-u.ac.jp

Decline of coral reefs have been concerned due to recent climate change and sea level rise.
However, the relationship between climate conditions and coral reef development is still
unknown. In this study, we reconstructed the composition of coral communities, coral carbonate
production, and climate condition (sea surface temperature; SST and salinity) from Holocene
uplifted terraces in Kikai Island, Japan, and discussed the relationship between reef growthpotential and climate change during mid to late Holocene.
Kikai Island is located at the central Ryukyus and on border between East China Sea and Pacific
Ocean. The coast of Kikai Island is composed by four terraces (Terrace Ⅰ - Ⅳ) developed from 8.1
ka to 1.4 ka. We measured topographic profiles and coral genus composition along four transects
crossed over from Terrace Ⅱ to Ⅳ (6.3 ka to 1.4 ka) around the Island. Coral carbonate production(CCP) in each terrace was calculated from the coverage, the skeletal density and the growth ratein each coral genus. Seasonal variation of SST and salinity were reconstructed by oxygen isotopes
and strontium/calcium ratios in fossil Porites corals sampled from each terrace.
The composition of coral community showed that Acropora sp., powerful reef builder, wasgenerally dominant in each site. The coverage of Acropora sp.was small on terrace Ⅲ at east coastand vice versa at west coast. The diversity of coral genus was increased with decreasing Acropora
sp. among each terrace. Average of CCP in four sites was 7.3 kg CaCO3 m-2 yr-1 at terrace Ⅱ anddecreased to 5.5 and 4.6 kg CaCO3 m-2 yr-1 at terrace Ⅲ and Ⅳ, respectively. CCP values weregenerally correlated with the coverage of Acropora sp. The seasonal variation of reconstructed
SST and salinity suggested the strength of east Asian monsoon.
These results revealed the relationship between climate and coral reef developments. Terrace Ⅱ
was highly developed under warm climate (Holocene climatic optimum) and strong summer
monsoon. On terrace Ⅲ at east coast, cooling climate decreased distribution of Acropora sp.and
CCP, however, coral diversity was increased to keep the reef growth. On terrace Ⅲ at west coast,strong winter monsoon (north west wind) developed coral reef. On terrace Ⅳ, the cover ofAcropora sp.and CCP were recovered with the transition to modern warm climate. Reef Corals
changed their diversity and have kept the reef growth through the Holocene in Kikai Island.

Session: Paleoecology and Evolution95

5th International Sclerochronology Conference, ISC 2019

Large-scale mapping of 143Nd/144Nd ratios in bivalve shells
for geographical traceability
Liqiang Zhao1*, Kentaro Tanaka1, Hirofumi Tazoe2, Tsuyoshi Iizuka3, Kaoru
Kubota4, Naoko Murakami-Sugihara1, Kotaro Shirai1
1

Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba 277-8564, Japan
Institute of Radiation Emergency Medicine, Hirosaki University, Aomori 036-8564, Japan3
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Tokyo 1130033, Japan
4
Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Nankoku
783-8502, Japan
2*presenting author: lzhao@aori.u-tokyo.ac.jp

Geographical traceability of marine bivalves is critical to guarantee their quality and safeguard theinterest of both consumers and producers. The neodymium isotopic ratio (143Nd/144Nd) of thecoastal water mainly reflects the geology of its neighboring watershed, displaying the distinct andsystematic variability at high level of geographical detail and thereby shedding light on its potential
as a geochemical tracer. For the first time, the present study investigated the utility androbustness of 143Nd/144Nd archived in mytilid mussel shells for geographical traceability purposes.
The consistency of 143Nd/144Nd ratios maintained in mussels shells from the same cohort
demonstrates that the Nd isotopic ratio meets the major requirement for an ideal geochemical
tracer, i.e., the biologically induced variation should be rather minimal. The distribution andvariability of mussel shell 143Nd/144Nd patterns were subsequently mapped along the Japanese andChinese coastal waters. Neodymium isotopes of mussel shells record 143Nd/144Nd variations
among local regions and between the two countries, which are rather compatible with the ages
and lithology of the continental bedrocks. These findings highlight the great potential of143
Nd/144Nd for tracing the geographical origin of marine bivalves.

Session: Fisheries Ecology and Management96

5th International Sclerochronology Conference, ISC 2019

Evidence that coralline red algae are tougher than wethought - Industrial era pH seasonality and long-term trends
in the Canadian Arctic Archipelago
Meghan Zulian1*, Jan Fietzke2, Jochen Halfar1
1
2

Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON, Canada
GEOMAR Helmholtz Zentrum für Ozeanforschung Kiel, Wischhofstr. 1-3, D-24148 Kiel, Germany*presenting author: meghan.zulian@mail.utoronto.ca

As anthropogenic carbon emissions reduce ocean pH, marine ecosystems will experience adverse
effects from acidification. Ecosystem models predict faster acidification rates for the Arctic ocean
due to their low alkalinity waters and near calcium carbonate under-saturation. In lower pH waters
calcification will require more energy, leading to declines in the survival of carbonate secretingorganisms. Despite the projected impacts of acidification, no high-resolution, continuous,
historical data exist for high Arctic Ocean pH.
The coralline red algae Clathromorphum compactum is the only established high-resolution,
continuous, paleoclimate pH proxy inhabiting the shallow high Arctic seafloor. Their growth is afunction of temperature and light availability. As C. compactum form annual growth increments,
they incorporate boron into their high magnesium calcite skeleton. Skeletal boron concentrations
and boron isotopic composition depend on environmental pH conditions. Throughout the multicentennial lifespan of C. compactum, it records seasonal pH dynamics and long-term trends.
Here, we examine seasonal and century scale pH dynamics in multiple locations from the Canadian
Arctic Archipelago (CAA), where sea ice duration limits annual growth of C. compactum to lessthan 100 μm. C. compactum boron concentration and isotopic composition were analyzed at 25
μm resolution, using laser ablation multi-collector inductively coupled mass spectrometry (LA-MCICPMS).
Our results indicate that throughout the CAA, B/C ratios and boron isotopes document distinct
changes in pH during the Industrial Era. Lower algal boron concentrations and lighter boron
isotopic composition indicate a strong pH decline post-1930, likely driven by anthropogenic carbon
emissions. The seasonal amplitude of recorded pH also increases by 50% post-1930, with summer
pH higher, and winter pH lower than any values in the 250-year algal record. Summer pH highs
and winter lows are likely a result of intensified primary productivity and the subsequent decay oforganic matter. Our data suggest that declining sea ice extent increases light availability,
permitting greater bulk primary production that sequesters CO2, and drives up ocean pH. In
winters when the organic material decays, CO2 is released to the environment, drawing down pH.
Despite the long-term acidification trend, annual growth of C. compactum continues to increase.
Thicker annual growth increments indicate that increased photosynthetic rates are compensating
for lower pH conditions, suggesting C. compactum maintains strong control over calcifying fluid
pH and may be less vulnerable to acidification than previously predicted.

Session: Climate and Oceans: Past, Present and Future97

Fishing vessel, Kaštela Bay, Croatia
Photo by Mišo Pavičić

Poster presentations

98

5th International Sclerochronology Conference, ISC 2019

Increment microstructure of the gladius in recent squid
helped to assess duration of ontogenetic phases in Jurassic
belemnites (Mollusca: Cephalopoda)
Alexander Arkhipkin1*, Robert Weis2, Zhanna Shcherbich1
1

Falkland Islands Fisheries Department, Bypass Road, Stanley, FIQQ 1ZZ, Falkland Islands
Palaeontological Department, National Museum of Natural History, 25 Rue Münster L-2160 Luxembourg,
Luxembourg
2*presenting author: aarkhipkin@fisheries.gov.fk

Belemnites originated in the Lower Jurassic and quickly became one of the most abundant coleoid
cephalopods that inhabited the shelves of Mesozoic seas. They had the functional phragmoconein the internal shell with counterweighted calcitic rostrum, giving them neutral buoyancy in thewater. The structure of the internal shell with the dorsal plate (proostracum) formed to theanterior side of their phragmocone left free the ventral part of the muscular mantle, enabling
belemnites to produce jet propulsive movements in analogy to modern cuttlefish. The shape ofthe rostrum of Jurassic belemnites, varying from short conical to long conical (sometimes with
developed posterior part called epirostrum) indicated that their swimming abilities were not asstrong as in their Cretaceous successors. Despite frequent occurrence of belemnite shells in
Mesozoic deposits, very little is known about their life cycles including duration of ontogenetic
phases and growth rates.
We have investigated microstructure of the rostra in the gladius of recent squid Onykia ingens andO. robusta (Onychoteuthidae) and Illex argentines (Ommastrephidae) and compared it with thatof the guards (rostra) of Jurassic belemnites. Those included Dactyloteuthis semistriataand
Acrocoelites riegrafi that formed an elongated epirostrum anteriorly to their orthorostrum in adultanimals, as well as several species of large Megateuthis that increased their rostral growth byforming non-dense aragonite layers in the inner part of their otherwise calcitic epirostrum. Growthincrements within the rostra of both recent squid and extinct belemnites had similar features thatmade it possible to date the formation of various zones within the rostrum microstructure bycounting growth micro-increments. Assuming daily nature of growth micro-increments, it waspossible to date ontogenetic stages that putatively correspond to the periods of late embryonicstage, hatching and formation of the orthorostrum and epirostrum and estimate their growth
rates and life span. It was found that belemnites lived generally longer than modern squid, from
2 years in small D. semistriata and A. riegrafi to 3-4 years in large Megateuthis spp. Taking into
account ontogenetic changes in the microstructure and shape of the rostra, a new hypothesis on
possible ecological role of tail formation in adult of Jurassic belemnites has been suggested.

Session: Paleoecology and Evolution99

5th International Sclerochronology Conference, ISC 2019

Unravelling native nanostructured details in high resolution
scanning electron microscopy (HRSEM) of wasted marine
biomaterials
Lucian Barbu-Tudoran1,2*, Maria Suciu1,2, Fran Nekvapil1,2, Simona Cinta
Pinzaru2, Branko Glamuzina3
1

National Institute For Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, Ro400293 Cluj-Napoca, Romania
2
Babes-Bolyai University, Kogalniceanu 1, RO-400084 Cluj-Napoca, Romania
3
University of Dubrovnik, Department for Aquaculture, Ćira Carića 4, 20000, Dubrovnik, Croatia*presenting author: lucianbarbu@yahoo.com

Ultrastructural approach for native biomaterials analysis with scanning electron microscopy
implies a series of smart sampling steps to be able to preserve the native details at nanoscale.
Organic scaffolds like chitin-protein fibrils in biomaterials exhibiting Bouligand pattern are
particularly difficult due to their sensitivity to the electron beam. Their real-time movement during
HR-SEM imaging makes the experimental data difficult to collect when nanoscale details are
aimed. Here we demonstrate using several marine biomaterials that their nanomorphology could
be imaged and unexpected particularities drives to novel bioinspired applications. Skeletonsfragments of sea creatures aimed for HR-SEM of their structural layers are very similar from thechemical point of view (calcium carbonate polymorphs) and extremely different and diverse frommorphological point of view. The differences were born from their different needs andadaptations. HR-SEM in conjunction with EDX and guided by preliminary Raman spectroscopy
analysis are crucial to approach down to nanometer size the delicate morphological details. For
example, sea urchins have a spongy calcite stereom with high magnesium content and with spinesthat contain glycoproteins. Pores are micron-sized and have an arranged spongy order withporosity of much interest for new biocomposites. Crabs' exoskeleton is much more compact, withnanometer-sized pores and with a considerable amount of protein content, in the form of orderly
layered protein foils between compact calcite sheets, all connected in a fabric-like structure oforganic and inorganic network. Understanding the complex formation of skeleton structures andfunction can provide valuable information about their possible applications and novel 3d-orderedstructures or their ability to capture and host certain pollutants.
Comparative nanometer scale HR-SEM images from biomaterials harvested from marineorganisms are discussed. Derived from their morphology and chemical properties, several
applications of sea urchins and crab skeletons porous biomaterial are highlighted.

Session: Biomineralization100

5th International Sclerochronology Conference, ISC 2019

Examining the potential of Pacific abalone as a novel highresolution archive of seasonal upwelling in the Channel
Islands, CA, USA
Christine N. Bassett1*, C. Fred T. Andrus1
1

The University of Alabama, Tuscaloosa, Alabama, USA*presenting author: cbassett@crimson.ua.edu

Upwelling is an important seasonal oceanographic process that brings up cold, nutrient-richwaters to the surface. These nutrients encourage the growth of phytoplankton and seaweed,
which form the foundation of most coastal food webs as well as the fisheries that depend on them.
Consequently, the occurrence of upwelling directly affects the health of coastal ecosystems, aswell the ability of human populations to depend on them for dietary resources. An array of proxies
from sediment cores inform the bulk of upwelling reconstructions throughout Earth’s history.
More recently, organisms which precipitate calcium carbonate skeletons have also provided
invaluable information from stable oxygen and carbon isotopes from which upwelling conditions
can be inferred. This study explores the potential of using stable isotope analysis of shells from
Pacific black abalone, Haliotis cracherodii (Leach 1817), in the Channel Islands. We present highresolution time-series stable nitrogen isotope data (δ 15N) that, together with table oxygen (δ 18O)
and carbon (δ13C) isotopes, reflect seasonal variability that is closely linked to upwelling andpropose a more comprehensive study that would measure seasonal variations in water properties
and nutrient availability in order to more confidently interpret variations recorded in abalone
shells. The implications of this research are twofold: The ability to reconstruct seasonal upwelling
patterns from abalone shell may provide more detailed knowledge on the cycling of nutrientsduring times of upwelling, and perhaps more importantly, during its absence. Furthermore, in the
Channel Islands, shell middens contain an abundance of both black and red abalone date back to
the early Holocene, meaning that reconstructions of upwelling can potentially span the entire
Holocene.

Session: Proxy Development: Challenges and Opportunities

1015th International Sclerochronology Conference, ISC 2019

Climate variability of North Atlantic water masses along the
Irminger Current: Insights from Arctica islandica shells fromSW Iceland
Fabian Bonitz1*, Carin Andersson1, Tamara Trofimova1, Vilde Melvik1, Madelyn
Mette11

Norwegian Research Centre, Bjerknes Centre for Climate Research, Bergen Norway, Jahnebakken 5, 5007
Bergen, Norway*presenting author: fabian.bonitz@norceresearch.no

The shells of the marine bivalve mollusc Arctica islandica have proven to be a valuable paleo proxyfor climatic and environmental conditions in the northern North Atlantic. In this study, we use
shell growth variability and stable oxygen isotope variability in A. islandica shells from the Faxaflói
area close to Reykjavik, SW Iceland to gain insights into the dynamics of northward flowing North
Atlantic water masses along the Irminger Current. The area SW of Iceland has not been targeted
for sclerochronological investigations so far. Thus, our results will enhance the network ofsclerochronologically-derived paleoclimate reconstructions in the North Atlantic. Further, ourstudy enables for the first time comparisons between sclerochronological data from northern
Iceland and SW Iceland, allowing for a detailed comparative study of two geographically similar
yet oceanographically distinct regions.
So far, 19 live-collected and 5 sub-fossil shells have been successfully cross-matched and havebeen used to construct a statistically robust master chronology spanning the last two centuries.
The chronology was compared to various instrumental data to determine the main forcing for theshell growth in this area as well as to other sclerochronological data from the northeastern North
Atlantic. Frequency analyses were applied to reveal recurrent modes of climate variability such as
the Atlantic Multi-decadal Variability and the North Atlantic Oscillation. In addition, annual d18Oshellsamples were taken from two specimens, providing a d18Oshellrecord covering 1890-2008.
Currently, more d18Oshell samples are being collected to extend the isotope chronology further
back in time. The preliminary d18Oshell record is negatively correlated with instrumental
temperature data from the area and a field correlation between the d18Oshell record and SST data
reveals strongest correlations along the main inflow branches of North Atlantic Waters into the
Arctic. This indicates that the temperature signal recorded in the chemical composition of theshells (d18Oshell) is a reliable proxy for water temperature estimates in the Iceland area.

Session: Climate and Oceans: Past, Present and Future102

5th International Sclerochronology Conference, ISC 2019

Coral calcification during the geological past – why was it sodifferent?
Thomas C. Brachert1*, Philipp Spreter1, Christine Perrin2, Markus Reuter1
1

University of Leipzig, Institute of Geophysics and Geology, Talstraße 35, 04103 Leipzig, Germany
SETE UMR5321, 2 Route du CNRS, 09200 Moulis, France; and: Centre Européen de Recherches en Préhistoire
Muséum National d´Histoire Naturelle HNHP UMR 7194 CNRS-MNHN, France
2*presenting author: brachert@uni-leipzig.de

The present increase in atmospheric carbon dioxide (pCO2) due to the burning of fuels is
unprecedented in earth history. As a result, ongoing ocean acidification increasingly endangers
marine calcareous biota such as reef corals. For testing predictions on the carbonate saturation
state of the surface ocean in reef settings over geological time, we present the first comprehensive
set of reef-coral sclerochronological records and calcification data from specimens being between
23 and 1 million years old. The sclerochronological data document environmental variability atannual and inter-annual time-scale compatible with the Recent. The calcification patterns of thefossil corals differ from corals in present-day reef settings (warm and oligotrophic), but are
indistinguishable from those in oceanic low carbonate supersaturation (CS) environments. Thisfinding may indicate to low seawater CS during the geological past. By now it is not clear, however,whether low CS was an effect of globally high pCO2, or local environmental stressors (lowtemperature, siltation stress, upwelling, etc.). We also find that investing calcification resources
preferentially in skeletal extension rather than skeletal density is a conservative evolutionary traitof the scleractinian reef corals. It reflects an adaption to colonizing space on a reef in low CS
environments of the past and likely was an essential pre-adaption to compete with rapid, deglacial
sea-level rises.

Session: Climate and Oceans: Past, Present and Future103

5th International Sclerochronology Conference, ISC 2019

Sclerochronology and stable isotope records (δ18O) of Lower
Jurassic lithiotid bivalves from the Trento Platform(Southern Alps, Italy)
Valentina Brandolese1*, Hideko Takayanagi2, Davide Bassi1, Thuy Thi Nhu Ha2,
Yasufumi Iryu2, Renato Posenato1
1

Department of Physics and Earth Sciences, University of Ferrara, via Saragat 1, 44122 Ferrara, Italy
Institute of Geology and Paleontology, Graduate School of Science, Tohoku University, Aobayama, Sendai,Japan
2*presenting author: valentina.brandolese@unife.it

Lithiotids are Lower Jurassic, mainly Pliensbachian, larger thick-shelled bivalves characterized byaberrant and frame-building morphologies. They include several gregarious taxa with a wide
geographical distribution in the Tethyan and Panthalassa shallow-water carbonate platforms,
where they built considerable biogenic accumulations. Since the large shell size has been so far
related to longevity or photosymbiosis, here we performed a sclerochronological study based ona high-resolution oxygen isotope records (δ18O). Carbon isotope data (δ13C) testing thephotosymbiosis hypothesis are in progress.
In the present study, the specimens with a complete and possibly almost complete original
aragonitic shell composition were analysed. The material was collected from the Rotzo Formation(Trento Platform, northern Italy) and includes following species: Cochlearites loppianus,
Lithioperna scutata, Lithiotis problematica, Opisoma excavatum, and Pachyrisma durga. Beside
the growth patterns, the study provided palaeoenvironmental and palaeoclimatic information.
Diagenetic screening (SEM and XRD analyses) were conducted on polished slabs, while thinsections were used for sclerochronological assessement.
In the feather-like areas of the cardinal area, Lithiotis and Cochlearitesshow growth periodicity
characterized by prominent regular intervals. These intervals were interpreted as annual growths.
Lithioperna usually shows thin dense and not well-defined ribs. Opisoma and Pachyrisma do notdisplay growth pattern on shell surface. In Cochlearites and Opisoma the δ18O shell profiles show
distinct sinusoidal oscillations related to regular seasonal growth cycles. In Cochlearites, the δ18O
profile confirms an annual periodicity of the first order growth lines occurring on the feather-likeareas. Lithioperna and Pachyrisma are characterized by less defined regular δ18O cycles
presumably due to the lower sampling resolution related to a lower growth rate.

Session: Paleoecology and Evolution

104

5th International Sclerochronology Conference, ISC 2019

Analysis of the persistence of seasonal stratification in thenorthern North Sea using a δ18Oshell - based bottom watertemperature reconstruction for the last 455 years
Juan Estrella-Martínez1, Bernd R. Schöne2, James D. Scourse3, Paul G. Butler3*
1

School of Ocean Sciences, Bangor University, Bangor, Wales, UK
Institute of Geosciences, Johannes Guttenberg University, Mainz, Germany
3
College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, UK2*presenting author: p.butler@exeter.ac.uk

The development of seasonal stratification in epicontinental seas Is a first-order hydrographic
phenomenon with physical, biological, biogeochemical and geological impacts. Instrumental
series of stratification dynamics are of very high resolution but they are limited to the very recent
past. Millennial-length proxy records, on the other hand, lack the temporal resolution required toassess the persistence of stratification under the influence of high frequency atmospheric forcings.
Here we present a c.500-year, annually-resolved, absolutely-dated bottom water temperature(BWT) reconstruction for the Fladen Ground, northern North Sea, based on the stable oxygenisotope geochemistry of Arctica islandica shells (δ18Oshell). Micromilling of samples from annual
increments yielded an annually resolved and precisely dated δ18Oshell record for the period 15512004 CE. Sub-annual sampling suggests that the average growing season of A. islandica in the
Fladen Ground extends from February to October. The reconstruction shows an averagetemperature of 7.20°C for the past c. 500 years, with warming trends of 0.05 ± 0.02°C decade-1 forthe years 1640-1740 and 0.08 ± 0.02 °C decade-1 for the years 1880-2001, and a cooling trend of 0.11 ± 0.02°C decade-1 for the years 1810-1910. These trends cannot be attributed to North
Atlantic sea surface temperatures (SST). 9-54 % of variability in average Feb-Oct BWT can be
attributed to low frequency changes in the winter North Atlantic Oscillation (NAO). Higher
frequency NAO variability does not show a consistent effect for any season. A BWT/SST regression
analysis suggests that the thermal stratification in the northern North Sea can be overturned by
local storm activity, but that it persists under calmer conditions and when the storm tracks passthrough the central and southern North Sea.

Session: Climate and Oceans: Past, Present and Future105

5th International Sclerochronology Conference, ISC 2019

Growth and age validation of thornback ray in the WestCentral Mediterranean basin
Pierluigi Carbonara1*, Andrea Bellodi2, Francesca Capezzuto3, Cristina Follesa2,
Giuseppe Lembo1, Porzia Maiorano3, Michele Palmisano1, Paola Pesci2, Maria
Teresa Spedicato1, Letizia Sion3
1

COISPA Tecnologia & Ricerca, Stazione Sperimentale per lo Studio delle Risorse del Mare, Via dei Trulli 18/20,
Torre a Mare (BA), Italy2
Dipartimento di Biologia Animale ed Ecologia, Universita di Cagliari, Cagliari, Italy
3
Department of Biology, University of Bari, Bari, Italy*presenting author: carbonara@coispa.it

Despite their evolutionary success, many chondrichthyans are increasingly threatened withextinction as a result of human activities and the conservative life history traits of this group offishes. In Mediterranean basin, the thornback ray (Raja clavata), represents among the Rajids themost commercially utilized species and it is actually included in the IUCN-RedList as Threatened
species. In particular, in the West-Central Mediterranean basin, where the fishing activity is welldeveloped, R. clavata represents one of the most important by-catch species mostly for thebottom trawl and long line fishery. Despite being a very widespread species, some gaps still exist
on its biology mostly on the growth pattern. The lack of biological data constitutes, for theMediterranean, one of the impediments in order to assess and take appropriate management
measures for this species. Indeed, stock-assessment models, particularly the analytical ones,
require growth parameters as important input data. The aim of the present study is to fill thisknowledge gap. Specimens of R. clavata were collected during the experimental trawl surveys,
commercial landings and discard monitoring in Sardinia, Central-Southern Tyrrhenian, West Ionianand South Adriatic Sea. Thin sections of vertebrae were performed in order to determinate theage and calculate the parameters of the von Bertalanffy growth function for both sexes in eachstudy area. Moreover, on specimens captured in Adriatic, Sardinia and West Ionian, the marginal
analysis of the vertebrae was also carried out as a semidirect ageing analysis validation. In the
Adriatic, a mark-recapture experiment, marking by both external (spaghetti tags) and chemical(oxytetracycline injection) tags, 98 specimens of R. clavata was also realized. In total two
recaptures after 11 and 14 months were recorded with an increment in total length respectivelyof 11.4 cm (from 49.5 to 60.9 cm) and 10.3 cm (from 63.5 to 73.8 cm). In both specimens
recaptured the oxytetracycline mark together with the subsequent deposition of a completed
annulus (one transparent and opaque ring) was observed on the sections of vertebrae.
The marginal analysis highlighted the deposition of one annulus (one opaque ring and one
transparent ring) per year. Moreover, the results from tag-recapture experiment seems validate
the age criteria adopted in this study to read the vertebrae of thornback ray in the West-Central
Mediterranean basin, although they are related to only two specimens.

Session: Fisheries Ecology and Management1065th International Sclerochronology Conference, ISC 2019

Ring deposition patterns in common sole otoliths from the
Adriatic Sea
Pierluigi Carbonara1*, Enrico Arneri2, Petra Bratina3, Loredana Casciaro1,
Sabrina Colella4, Ilija Cetković5, Fortunata Donato4, Robert Grgičević6, Nicoletta
Milone2, Tomaz Modic3, Giulio Pellini4, Stefan Ralević5, Nedo Vrgoč6, Giuseppe
Scarcella4
1

COISPA Tecnologia & Ricerca, Via dei Trulli 18/20, Torre a Mare (BA), Italy
FAO-AdriaMed Project, Viale delle Terme di Caracalla, 00153 Roma, Italy3
Fisheries Research Institute of Slovenia, Sp. Gameljne 61, SI-1211 Ljubljana-Šmartno, Slovenia
4
Istituto per le Risorse Biologiche e le Biotecnologie Marine (CNR-IRBIM) Largo Fiera della Pesca, 1 60125,
Ancona, Italy
5
University of Montenegro - Institute of Marine Biology of Kotor, PO Box 69--85330 Kotor, Montenegro
6
Institute of Oceanography and Fisheries, Š. Ivana Meštrovića 63, 21000 Split, Croatia
2*presenting author: carbonara@coispa.it

Common sole (Solea solea) represent one of the most commercially important fishery resources
for the Mediterranean basin and in particular for the Adriatic Sea. As for other exploited resources,
age and growth estimations are essential to study life-history traits, and in turn to understand the
population dynamics thus providing indication to proper manage the stocks. Fish ageing analysis
relies on the presence on calcified structures (e.g. otolith, vertebrae, scale) with a structural
pattern of growth rings in terms of succession of opaque and translucent zones, as well on
knowledge of the periodicity of the deposition and growth pattern. The seasonal appearance of
opaque and translucent rings in the whole otolith of flatfish shows a reversal pattern for otoliths
as regards fishes of temperate and cold water. However, the deposition pattern of theopaque/translucent area for the S. solea in the Adriatic is poorly known or based on studies fromthe 80s. Therefore, the aim of the present work is to investigate the deposition pattern on soleotoliths by qualitative (marginal analysis, MA) and quantitative (marginal increment analysis, MIA)
methods as a semi-direct age validation approach. The otoliths analyzed are part of a common set
of otoliths shared by the research institutions of five countries in the Adriatic Sea. Indeed, thedeposition pattern shall be determined as the first step to understand whether the increments
are laid down according to a periodicity related to a regular time scale. The results obtained showthat one transparent and opaque area per year are laid down in S. solea in the Adriatic Sea. The
transparent zone is laid down between July and December, while the opaque between Januaryand June. The marginal increment analysis shows a significant otolith growth higher in thewinter/early-spring months. Moreover, these results are compared with previous data tounderstand if the increase of Adriatic water temperature has influenced the growth/deposition of
the common sole otoliths. The results of the MA and MIA are strategic for the defininition of thenumber of annulus/i laid down per year; the margin type represents a key element to obtain aclear age scheme that improve the standardization of age analysis, by increasing the
reproducibility between age readers.

Session: Fisheries Ecology and Management107

5th International Sclerochronology Conference, ISC 2019

Extended chronology of the bivalve Serripes groenlandicus
from a high-Arctic fjord in Svalbard, Norway
Michael Carroll1*, William Ambrose2, Colin Eimers3, Amanda Eller4
1

Akvaplan-niva, Fram Centre for Climate and Environment, 9296 Tromsø, Norway
Coastal Carolina University, School of the Coastal Environment, Conway, South Carolina, 29528, USA
3
University of Maine, School of Marine Sciences, Orono, Maine, 04469, USA
4
Bates College, Department of Biology, Lewiston, Maine, 04240, USA
2*presenting author: mc@akvaplan.niva.no

Knowledge of how marine organisms are influenced by past climate may help us better
understand how they will respond to climate change. Climate change is occurring rapidly in the
Arctic, so observing the links between change and biological effects there can provide key
information on the ecosystem consequences of climate change in the world's oceans. Analysis ofshell-based records of mollusks (sclerochronology) provides an approach to reconstructing
environmental-ecological linkages. We explored the relationship between large-scale climate
regimes, local environmental conditions, and the growth of the Greenland Cockle (Serripes
groenlandicus) from Rijpfjorden, a high-arctic fjord in Svalbard, Norway (80°10’N, 22°15’E).
Ambrose et al. (2006, Global Change Biology 12, 1595-1607) published a 22-year growthchronology, spanning 1981 through 2002, based on samples collected in 2003. Here we extend
the growth chronology through 2017 (based on samples collected in 2007, 2010, 2012, 2013, and2017), increase the sample size to 80 individuals, and examine the influence of environmental
variables on the extended 37-year chronology.
Individuals ranged in age from 5-29 years, and raw shell increment series were detrended withthe von Bertalanffy growth function to obtain a Standard Growth Index (SGI) for all samples. SGI
ranged from a low of 0.6 in 1988 to a high of 1.6 in 1994. From the peak SGIs in the mid-1990s,
there has been a steady downward trend despite smaller-magnitude oscillation cycles of 5-6 years.
Temperature of the West Spitsbergen Current (WSC) explained the most variability in shell growth(R2 = 0.33), while the WSC, the Arctic Climate Regime Index (ACRI) and maximum arctic-wide sea
ice cover explained a total of 62% of the interannual growth variability. We will also explore
temporal trends within the environmental regulation of the growth chrononology, i.e. variation in
the environmental factors most strongly associated with shell growth in the original chronology
from Ambrose et al. 2006 and in the updated master chronology. These results suggest that theGreenland Cockle is quite sensitive to environmental changes over annual to decadal scales andtherefore can serve as a proxy of climate change effects on ecosystem processes in the Arctic.

Session: Growth, Bioenergetics and Ecosystems

108

5th International Sclerochronology Conference, ISC 2019

Micro-chemical and micro-mineralogical techniques forsclerochronological studies – which one should I choose?
Simon Chenery1*, Charlotte Colvin2, Pedro Freitas3,4, Phil Hollyman2,5,
Konstantin Ignatyev6, Ion Microprobe Facility7, Andy Marriott1, Ian McCarthy2,
Chris Richardson2
1

Centre for Environmental Geochemistry, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
School of Ocean Sciences, College of Environmental Sciences and Engineering, Bangor University, Menai Bridge,
LL59 5AB, UK
3
Danish Shellfish Centre, Technical University of Denmark, Øroddevej 80, 7900 Nykøbing M, Denmark4
Instituto Português do Mar e da Atmosfera (IPMA), Rua Alfredo Magalhães Ramalho, 1495-006 Lisboa,
Portugal
5
British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
6
Diamond Light Source, Harwell Campus, Didcot, Oxon, OX11 0DE, UK
7
Ion Microprobe Facility, Edinburgh University, Edinburgh, EH9 3JW, UK
2*presenting author: srch@bgs.ac.uk

Our multi-institute research group have been using micro-chemical and micro-mineralogical
techniques as investigative tools for sclerochronological studies of shells, statoliths and fish
otoliths for more than two decades. The primary technique used, has been point analysis by laser
ablation-ICP-MS. This provided spatial trace element concentrations and Sr isotopic data on
several hundred points per day, typically at 20-50 micron resolution. Considerable valuable
information has been gained, but has been limited due to the small fraction of the total area of ashell measured or insufficient fine-scale resolution for chemical banding in small structures, suchas statoliths. Our recent investigations have made use of the ion-probe for precise small spot
analysis (2 micron) and synchrotron micro-XRF to map Sr concentrations at a similar scale. The
synchrotron provides mineralogical information on which calcium carbonate polymorphs exist,
using micro-XRD and molecular structural information via XANES and EXAFS. With limited accessto a synchrotron Raman spectroscopy has been investigated as an alternative for providing
mineralogical information. Laser ablation as a technique has not stood still, with recent advancesin the laser ablation systems coupled with increasingly sensitive ICP-MS is revolutionizing traceelement mapping in terms of data acquisition speed. In this presentation we will briefly explore
and review, using examples, what each technique has to offer sclerochronology and theiradvantages and limitations, with the aim of helping others to best choose from this menu oftechniques for their own applications.

Session: Biomineralization109

5th International Sclerochronology Conference, ISC 2019

Determining spatial and temporal compositional variation in
Buccinum undatum shells
Charlotte Colvin1*, Philip Hollyman2,3, Simon Chenery3, Chris Richardson1,
Konstantin Ignatyev4, Ian McCarthy1
1School of Ocean Sciences, College of Natural Science, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK
British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
3
Centre for Environmental Geochemistry, British Geological Survey, Keyworth, Nottingham, G12 5GG, UK
4
Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
2*presenting author: ospa5d@bangor.ac.uk

Trace element variations in mollusc shells are studied as proxies for historical conditions, e.g.
seawater temperature. These proxies may also vary due to animal physiology and shellmineralogy. The commercially important whelk Buccinum undatum, frequently experiences
damage from anthropogenic activities and unsuccessful predatory attacks. As an example of this,the process of removing under-sized animals for release can cause damage to shells as they are
passed through a series of metal bars called a “riddle”. All of these damage incidences combine todelay normal shell growth and thicken the shells through re-growth. The shells of B. undatum,form as a solid calcareous exoskeleton are formed of 4 distinct layers of aragonite around thecentral columella.
LA-ICP-MS was used to determine concentrations of key trace elements (Sr, Mg, U, Ba, Fe, Mn andNa) both within and between shell layers. Crystallographic (μXRD), fluorescence (μXRF) andabsorption (μXANES/EXAFS) techniques on the Diamond I-18 microspectroscopy beamline werethen used to further establish differences in shell mineralogy and crystal structure in response tolaboratory-controlled shell damage and re-growth.
Results from LA-ICP-MS have shown concentrations of trace elements to significantly change
during periods of rapid growth between the newly formed shell layers, with differing chemicalcompositions amplified in areas of rapid growth and shell repair. Mapping using the μXRF
confirmed the Sr elemental distributions whereas the μXRD show mineralogical changes between
layers to be minimal.

Session: Biomineralization

110

5th International Sclerochronology Conference, ISC 2019

Deciphering high resolution structural and geochemicalsignals present in Stromatoporoids from the upper
CretaceousThierry Corrège1*, Laurent Londeix1, Josue Polanco-Martinez2, Luc Feuillerat1,
Badr Bennani1, Mériadec Le Pabic1
1

UMR 5805 EPOC, Université de Bordeaux, Pessac, France
Econometrics Research Group (ERG), Institute of Public Economics (IEP), University of the Basque Country,
Bilbao, Spain
2*presenting author: thierry.correge@u-bordeaux.fr

Stromatoporoids flourished during the Paleozoic and the Mesozoic, but are now extinct. Theirtaxonomic classification is still debated, although they are generally considered as Porifera.
Actinostromaria stellata (Stromatoporoids) collected from the southwest of France (Ile Madame,
Charente) and dating from the Cenomanian (Upper Cretaceous) possess an extremely dense andwell-preserved low-Mg calcitic skeleton. The skeleton is composed of fine laminae and pillars, andshow conspicuous banding, several mm wide. The banding is an alternance of light and dark bands,
similar to the density banding present in most massive corals. The growth rate of Stromatoporoids
has been studied by various authors, with no consensus being reached. Some consider that thelaminae may be annual, while others consider that it is the colour banding which is annual. To
assess the origin of these bands, and their potential as paleoclimatic and paleoenvironmentalarchives, their nature was investigated using high resolution scans of polished sections, thinsections, scanning electron microscopic observations, and geochemical analyses.
Three specimens of Actinostromaria stellata were slabbed and polished. The slabs were scanned
at high resolution (typically 8 µm), and the distance between laminae was measured across severaltransects. This distance ranges from 153 to 180 µm. Grey levels were also measured on thetransects. Spectral analyses were conducted on both the inter-laminae distance and the grey level.
Two specimens reveal a periodicity of 24 to 27 laminae, which is consistent with the number oflaminae present in a couplet of light and dark bands. The third specimen yielded a periodicity of
33 laminae, slightly higher than the two others.
Geochemical analyses of Mg/Ca and Sr/Ca were conducted at high resolution (i.e. every 400 µm)
along the same transects. They reveal a variability linked to the colour banding, and similar toannual cycles of sea surface temperature seen in corals.
It seems therefore likely that the colour banding present in Actinostromaria stellata is annual. The
cause for this difference in colour is still being investigated, as SEM observation did not yield any
clue. The number of laminae per year is unusual, ranging from 24-27 to 33. A possibility could bethat laminae deposition was linked to the tidal cycle.

Session: Proxy Development: Challenges and Opportunities111

5th International Sclerochronology Conference, ISC 2019

Bivalve shells as archives of seasonality during the early
Pleistocene in the Mediterranean Sea
Gaia Crippa1*, Lucia Angiolini1, Fabrizio Felletti1, Melanie Leng2, Gianluca
Raineri3
1

Università degli Studi di Milano, Dipartimento di Scienze della Terra ‘A. Desio’, via Mangiagalli 34, Milano,
20133, Italy
2
NERC Isotope Geosciences Facilities, British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
3
Parco Regionale dello Stirone e del Piacenziano, Loc. Millepioppi, Salsomaggiore Terme, 43039, Italy*presenting author: gaia.crippa@unimi.it

The early Pleistocene is characterised by several climatic oscillations linked to glacial/interglacial
cycles. The Mediterranean area was strongly affected by these climatic oscillations in both marine
and continental settings; in the marine environment the most important biotic event isrepresented by the appearance of the “northern guests” – such as the bivalve Arctica islandica –at the beginning of the Calabrian, suggesting a progressive climatic deterioration (i.e., cooling) in
the Mediterranean region.
The lower Pleistocene (Calabrian) Arda River marine succession, cropping out in Northern Italy,
deposited continuously during this time interval; it represents an ideal site to study the climaticoscillations of the early Pleistocene using pristine bivalve shells as geochemical archives tounderstand if and how seasonality varied in this interval. The marine succession represents the
subaqueous extension of a fluvial system, originated during phases of advance of fan deltas
affected by high-density flows triggered by river floods, which are an expression of early
Pleistocene climate changes. The top of the succession is bounded by conglomerates indicating asea level drop and the establishment of a continental environment, testifying the approaching of
the Middle and Upper Pleistocene continental glaciations.
249 fossil bivalve shells belonging to species of Glycymeris, Aequipecten and Arctica, collectedfrom 141 beds were analysed for bulk shell isotopic compositions (δ18O, δ13C), after having
checked their preservation. Ten pristine bivalve shells (A. islandica and Glycymeris spp.) collectedfrom six discrete intervals along the section were sclerochemically analysed (δ18O, δ13C) toreconstruct seasonality.
The sclerochemical analyses indicate an increase in seawater temperature seasonality through theearly Pleistocene. However, the isotope data from the bulk shells do not indicate cooling of overall
sea surface temperatures throughout the interval, except for a significantly cold and seasonal
event at the first occurrence of Arctica islandica. Strong seasonality and low winterpalaeotemperatures were assumed to be the main drivers for the widespread establishment of
the "northern guests" populations in the Palaeo-Adriatic Sea around 1.80 Ma. This study indicatesthat the variations in seawater temperature seasonality was the main variable of climate change
within the study area, preparing the ground for the onset and establishment of the Middle andUpper Pleistocene continental glaciations.

Session: Paleoecology and Evolution112

5th International Sclerochronology Conference, ISC 2019

Highlighting inter-individual variability in Patella vulgata
shell growth: what consequences for paleo-environmental
proxies?
Jean-François Cudennec1*, Yves-Marie Paulet1
1

Institut Universitaire Européen de la Mer, Technopôle Brest-Iroise, Rue Dumont d'Urville, 29280 Plouzané,France*presenting author: JeanFrancois.Cudennec@univ-Brest.fr

To achieve reliable paleoenvironmental reconstructions from biogenic carbonates of marine
molluscs, growth model of the studied species must be well known. In mollusc shells, growthmarks produced in response to different rhythmicities (lunar-daily, fortnightly, annual) are usedas milestones for estimating and measuring growth patterns, from the daily scale to the whole lifeof the individuals. For this purpose, it is necessary to develop a toolkit based on present-day shells
to understand the recording of environmental variables in the carbonates.
Several recent studies are using sclerochemical analyzes of oxygen isotopes in shells of theintertidal gastropod Patella vulgate to perform paleo-SST reconstructions. We have studied
growth in this species through several approaches, including population studies on the shore,
calcein marks experiment and the study of different growth rings in the shells.
The results highlight a very strong inter-individual variability, questioning the size/age relationshipin this species. Various environmental factors (SST, tidal coefficients) have been taken into accountin an attempt to explain this variability and its impact on the high-resolution δ 18O profiles used
for paleo-environmental reconstructions. This variability rises the question of the interest ofclassical methods of growth rings studies in Patella vulgata, which cannot for the moment be used
to enlighten growth cessation periods on δ18O profiles.

Session: Proxy Development: Challenges and Opportunities

113

5th International Sclerochronology Conference, ISC 2019

Structural order in biogenic carbonates: Screening fordiagenesis with FTIR
Marisa Dusseault1*, Meghan Burchell2, Kristin M. Pouduska1
1
2

Department of Physics and Physical Oceanography, Memorial University, St. John's, NF A1C 5S7, Canada
Department of Archaeology, Memorial University, 310 Prince Philip Drive, St. John's, NF A1C 5S7, Canada*presenting author: mad872@mun.ca

Fourier Transform Infrared spectroscopy records the chemical composition and crystal structureof a material by probing a sample with infrared radiation, which is absorbed by the sample’s
vibrational modes. This method is useful for distinguishing between polymorphs – substances thathave the same chemical composition but different crystal structures. The two most common
polymorphs of calcium carbonate (CaCO3) are calcite and aragonite – also the most common
minerals composing mollusk shells. In addition to being useful for identifying the crystals of calcite
and aragonite, FTIR can also be used to analyze amorphous substances which allows us to assessthe degree of structural disorder within a sample. Studies implementing analyses and methods
that provide such information have been applied to archaeological calcite samples but have notbeen used previously to analyze bivalve mollusks from shell midden sites. The data obtained fromFTIR analyses can provide information on chemical composition, crystal structure, and diagenesis;
providing critical information to evaluate the diagenesis and the suitability of the sample for stable
isotope and radiocarbon analysis. To illustrate this, we show that comparing relative peakintensities in FTIR spectra can be used to understand the degree of structural disorder withinsamples of aragonite from archaeological mollusks. We use samples from three distinct
archaeological and geographic contexts to explore variability in shell structure and preservation:1) Saxidomus gigantea, from British Columbia (~4000-2000 years BP); 2) Mya Arenaria from Nova
Scotia (~1500-1000 years BP); 3) Pomecea palludosa from Cuba (~1700 years BP). To further
understand cultural and environmental post-depositional alteration in shell, we tested shells fromcontrolled boiling and roasting experiments, and also selected sun-bleached specimens withvisible outer damage to the shell surface. The inner and outer layers of all shell samples are
distinguishable when analyzing the relative peak intensities of multiple FTIR spectra, whichindicates differing degrees of structural disorder. These differences are not detectable whenanalyzing individual spectra. Further research will combine these methods with growth data,
radiocarbon and stable oxygen and carbon isotope analyses to study how sample preservationand diagenesis is linked to radiocarbon variability.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

114

5th International Sclerochronology Conference, ISC 2019

Sclerochronology of oyster shells – differences in trace andminor element composition between native Ostrea edulis
and invasive Magallana gigas
Krešimir Markulin1, Hana Uvanović1, Daria Ezgeta-Balić1*, Regina Mertz-Kraus2,
Melita Peharda1, Ivan Župan3
1

Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia
Institute of Geosciences, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 21, 55128 Mainz,
Germany3
Department of Ecology, Agronomy and Aquaculture, University of Zadar, Trg Kneza Višeslava 9, 23000 Zadar,
Croatia2*presenting author: ezgeta@izor.hr

In the northern Adriatic Sea, European flat oyster Ostrea edulis and invasive Pacific oyster
Magallana gigas coexist in the same area. Growth performance of oysters is one of the mostimportant parameters in terms of O. edulis aquaculture and in terms of M. gigas invasion success.
As both species do not have clear periodic growth lines on their outer shells or in shell crosssections they are both a challenging species for ontogenetic age determination.
Objectives of this study were: (i) to estimate the potential of LA-ICMP-MS analysis for ontogenetic
age determination of oyster shells, (ii) to compare trace and minor element composition within
and between shells of two species, (iii) to compare results obtained for oysters with geochemical
results previously obtained for other bivalve species in the Adriatic Sea, (iv) to evaluate thepotential of oyster shells as environmental archives.
Oysters shells were collected alive in November 2017 from the aquaculture farm in the Lim
channel, in the North Adriatic Sea. Three similar sized specimens of each species were prepared
for the analysis. Analyses were performed at the Institute of Geosciences, JGU, Mainz, Germany,
using LA-ICP-MS. Analyses yielded high resolution time-series of Na/Cashell, Mg/Cashell, Mn/Cashell,
Sr/Cashell, Zn/Cashell and Ba/Cashell. Since oysters do not have clear periodic growth lines in shellcross sections of their hinge area, obtained chemical data could not directly associate to certain
calendar years. Furthermore, time series of trace and minor element composition to calcium ratios
had low reproducibility among different individuals and between different species. Evidence ofyearly cyclicity in Na/Cashell, Mg/Cashell, and Sr/Cashell ratios, previously found for shellsof Glycymeris pilosa, Callista chione, and Venus verrucosa from the Adriatic Sea (Markulin et al.,unpublished data), were only hinted for Mg/Cashell time series obtained from oysters indicating its
potential use in estimating age and growth. Na/Cashell time-series showed higher values in M.
gigas than in O. edulis. Oyster species showed higher values of Zn/Cashell and Mn/Cashell and lower
values of Ba/Cashell in comparison to other analyzed bivalve species from the Adriatic Sea (Markulin
et al., unpublished data). Uneven and irregular growth of oysters could be the reason of low
reproducibility among different individuals, and future data should aim to find and study shellparts that are comparable among different individuals.

Session: Proxy Development: Challenges and Opportunities

115

5th International Sclerochronology Conference, ISC 2019

Bivalve mollusk sclerochronology in a changing world:
Environmental controls on the growth of Mercenaria
mercenaria from North Carolina, USA
David H. Goodwin1*, David P. Gillikin2, Alan D. Wanamaker Jr.3
1

Department of Geosciences, Denison University, Granville, OH 43023, USA
Geology Department, Union College, Schenectady, NY 12308, USA
3
Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA 50011, USA
2*presenting author: goodwind@denison.edu

Bivalve mollusks shells archive environmental conditions in the form of biogeochemical variations
and periodic growth lines and increments. When calibrated with observed environmental records,
these archives become valuable sources of (paleo)autecological information. Here we present new
information of the growth of Mercenaria mercenaria from Jarrett Bay, in the Cape Lookout regionof North Carolina, USA. Environmental records were collected between August 2016 and June
2018. Hourly water temperatures were recorded with multiple in situ loggers in Jarrett Bay(±0.2°C). Weekly water samples were collected from the same site between August 2016 and June2018 (n = 89), to determine water oxygen isotope (d18OW) variation (analytical uncertainty±0.07‰). In addition, regional water sample transects collected in April 2017; October 2017; and,June 2018 document d18OW spatial variability in the spring, summer, and autumn seasons,respectively. Daily maximum and minimum temperatures, together with interpolated daily d18Ow
values from Jarrett Bay, were used to calculate the predicted carbonate oxygen isotope (d18OC)
envelope (i.e., the daily range of potential d18OC values). Multiple specimens of M. mercenaria
were grown under natural conditions at the same site between 2016-2018. Clams were stainedwith calcein, which fluoresces under UV light, on three dates: 8/13/16; 4/8/17; and, 7/13/17.
Shells were then collected on 10/21/17. Carbonate samples were collected from thick-sections
using a computer-controlled XYZ micromill. Analytical uncertainty of measured d18OC samples was±0.07‰. Measured d18OC samples were fit within the oxygen isotope envelope using the stained
samples and known collection date to calibrate the timing of shell growth. Our results suggest M.
mercenaria in Jarrett Bay grow essentially throughout the year. Surprisingly, the dark annual
bands, thought to form between May and October, were deposited between early April andOctober. These bands likely reflect heat stress and may reflect earlier warming of Jarrett Bay
waters in the spring. Placement of the measured d18OC samples in the oxygen isotope envelope
suggests these specimens grew preferentially during the warm hours of the day. Finally, our results
suggest these specimens stopped growing during the extreme precipitation event, Tropical Storm
Julia (September 2016). If these storm-induced growth cessations can be recognized it may
provide a new tool for reconstruction of prehistoric tropical storms.

Session: Growth, Bioenergetics and Ecosystems

116

5th International Sclerochronology Conference, ISC 2019

The carpet shell Ruditapes decussatus in archaeologicalcontext: insights on season of collection and coastal paleotemperature
Marc Gosselin1*, Catherine Dupont1, Céline Poulain2, Xavier Le Coz3, Gregor
Marchand1, Jean-Marie Munaron2, Christine Paillard2, Yves-Marie Paulet2,
François Plustoc’h1, Julien Thébault2
1

CNRS, UMR 6566 CReAAH « Centre de Recherche en Archéologie Archéosciences Histoire » Université deRennes, 35000 Rennes, France
2
LEMAR, UMR 6539 CNRS/UBO/IRD/IFREMER, Institut Universitaire Européen de la Mer, Place Nicolas Copernic,
29280 Plouzané, France
3
Géosciences Rennes Atelier Géomatériaux, UMR 6118 CNRS, OSUR, Université de Rennes 1, 35042 Rennes
cedex, France*presenting author: mar.gosselin@gmail.com

Specimens of carpet shell Ruditapes decussatus from the Mesolithic shell midden (6th millenniumBC) of Beg-an-Dorchenn (Brittany, France) were studied in order to access their period of collectas well as some insight on Paleo-temperature reconstructions. Cross sectioned shells display veryclear growth structures free from diageneses allowing to assess a growth rhythm of 2 increments
per lunar day. From this temporal framework, daily growth increments, fortnightly ridges, winterannual growth break and spawning events were characterized. The R. decussatus studied shells
collected in late autumn and/or early spring period. Chemical analyses of shell carbonates werealso conducted to access a preliminary range of potential sea temperature data from oxygenisotopes values (δ18Oshell). δ18Oshell shows seasonal variations but do not displays the whole rangeof temperature as R. decussatus have a growth break during winter. However, the range ofreconstructed SST did not show nonsensical values and suggest sea temperatures slightly higher
than the current ones. Thus, R. decussatus is particularly suited to address paleo-environmental
issue at high temporal resolution such as the seasonal periodicity. To conclude additionalsclerochronological and chemical researches on other mollusk species from Beg-an-Dorchenn orother Mesolithic shell middens along the European Atlantic façade will contribute to the
problematics of seasonal occupation as well as climate variability at the Mesolithic-Neolithic
transition.
This work was supported by the EPT of the European University of Brittany PROXARCHEOBIO France (2010-2012 / CReAAH-LEMAR Leader C Dupont) France, the scientific challenges of the
University of Rennes 1 « SMS Shell-Middens Seasonality (2017 / Leader C. Dupont) » and private
donations (2017).

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

1175th International Sclerochronology Conference, ISC 2019

Reconstruction of Arctic Oscillation driven sea ice variabilityin Lancaster Sound, Canadian Arctic, using the long-lived
coralline alga Clathromorphum compactum
Jochen Halfar1*, Annelotte Van der Linden2, Kent Moore1, Sarah Shana1, Sasha
Tsay3, Zoltan Zajacz3
1

Department of Chemical and Physical Sciences, University of Toronto at Mississauga, 3359 Mississauga Rd. N,
Mississauga, ON, L5L 1C6, Canada
2
Department of Earth Sciences, Utrecht University, Princetonlaan 8a, 3584 CB Utrecht, Netherlands
3
Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto, ON, M5S 3B1, Canada*presenting author: jochen.halfar@utoronto.ca

Arctic sea ice cover has been rapidly declining since the beginning of satellite observations in the
1970s. However, limited length satellite records do not allow for an assessment of the long-term
behaviour of sea ice. Recently, the shallow benthic coralline alga Clathromorphum compactum has
been shown to archive annual resolution proxy information of sea ice cover. C. compactum isfound throughout the Arctic and can exhibit a life-span of up to 650 years while depositing annual
growth increments in a High-Mg calcite skeleton. Annual growth increment widths and Mg/Ca
ratios in this photosynthesizing marine plant are strongly dependent on light availability on theshallow seafloor, where low growth rates and Mg/Ca ratios are related to long duration sea-ice
cover. Here, we have analyzed Mg/Ca ratios in two specimens of C. compactum live-collected from
Lancaster Sound, Nunavut, Canada in summer 2016. Mg/Ca ratios exhibit annual cyclicities, whichwere used to calculate annual growth increment widths and generate an age model extending
back to 1863. The sea-ice proxy was constructed by averaging of annual growth increment widthand Mg/Ca anomalies of both samples. Proxy strength was tested by comparison with satellite
derived regional summer sea ice concentration data between 1979-2015 yielding significant
negative relationships (western Lancaster Sound r=-0.8, p<0.0001; central Lancaster Sound r=-0.4,
p<0.03). Spatial comparisons with satellite-derived sea-ice concentrations across the Canadian
Arctic Archipelago exhibit highest correlations in the western-central Lancaster Sound and Barrow
Strait region, further confirming the suitability of C. compactum for regional scale sea-ice
reconstructions. The algal time series prior to satellite observations indicates a long-term sea-ice
decline which was most pronounced between 1910-1950 followed by a period high sea-ice coverfrom the 1960s to 1980s. Lancaster Sound sea ice anomalies have previously been related tovariability of the Arctic Oscillation (AO) - a measure of Northern Hemisphere sea-level pressure
differences determining the exchange of atmospheric mass between the Arctic and mid-latitudes.
The AO influences Lancaster Sound through wind patterns, where a positive AO results in strong
winds driving ice out of the Sound. Variability of the algal sea ice reconstruction is closely related
to an AO index (rannual=0.67, p<0.0001, 1899-2000) demonstrating the long-term stability of thesea-ice – AO relationship in Lancaster Sound. However, from 2000 onwards algal anomalies
indicate a steep decline in sea ice unrelated to the AO, suggesting that Lancaster Sound sea-ice
variability has started to respond to other drivers, such as increasing Arctic temperatures.

Session: Climate and Oceans: Past, Present and Future118

5th International Sclerochronology Conference, ISC 2019

Annually resolved NE Atlantic Ocean variability through the
8.2K cold event
Ian Hall1*, David Reynolds2, Sophie Slater1, James Scourse3, Paul Halloran4,
Freya Garry4
1

School of Earth and Ocean Science, Cardiff University, Main Building, Park Place, Cardiff, CG10 3AT, UK
Laboratory of Tree Ring Research, University of Arizona, Bryant Bannister Tree Ring Building, 1215 E Lowell St,
Tucson, AZ, 85721, USA
3
Centre for Geography and Environmental Science, College of Life and Environmental Science, University of
Exeter, Penryn Campus, Treliever Road, Penryn, Cornwall, TR10 9FE, UK
4School of Geography, College of Life and Environmental Science, University of Exeter, North Park Road, Exeter,EX4 4QE, UK
2*presenting author: hall@cardiff.ac.uk

The 8.2K event is regarded as one of the largest climate perturbations of the Holocene, whichbrought generally widespread, especially wintertime, cold and dry conditions to northernhemisphere regions, in response to a very large outburst flood that freshened the North Atlantic.
As a result, it is suggested that the Atlantic Meridional Overturning Circulation (AMOC)
significantly weakened. Understanding the response of the AMOC to rapid freshening in the
subpolar North Atlantic Ocean is of significant interest due to the role AMOC plays in heattransport from the tropics to the mid and polar latitudes as well as the potential for significant
socioeconomic impacts if, as numeric climate models predict, the AMOC weakens over the 21st
century in response to increased fresh water input from melting ice due to anthropogenic
warming. Here we report the stable isotopic composition (d18Oshell and d13Cshell) of live and fossil
G. glycymeris shells collected from the Tiree Passage in northwest Scotland. These shells spanned
two distinct intervals from ca. 8900 BP to 8000 BP (i.e. spanning the 8.2K event) and 800 CE to2011 CE. The isotopic data, from both intervals, are characterised by significant inter-annual tocentennial scale variability with the coldest temperatures over the last millennium occurring
between 1500 CE and 1800 CE and, for the 8.2K event shells, between 8300 BP and 8400 BP. The
timing of the cold interval over the last millennium coincides with the Little Ice Age, whilst thecoldest interval from the 8k shells is broadly consistent with the timing of the 8.2K event. The
comparison of the d18Oshell data with the corresponding d13Cshell data, which is sensitive to changes
in salinity, suggest there were likely large shifts in both sea water temperature and salinity during
the 8.2K event in this region. Given the proven sensitivity of hydrographic variability in Northwest
Scotland to changes in North Atlantic Ocean circulation patterns, and the fortunate timing of theshell collections that capture the 8.2k event and variability over the last millennium, these data
may facilitate the attribution of the role of the AMOC in driving climate variability over the last
millennium and help constrain uncertainties associated with quantifying the current state of
AMOC variability.

Session: Climate and Oceans: Past, Present and Future

119

5th International Sclerochronology Conference, ISC 2019

Age estimation and corroboration of four-spot megrim(Lepidorhombus boscii) on the Porcupine Bank (west of
Ireland)
Carmen Hernández1*, Jorge Landa11Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Santander, Promontorio de San Martín s/n,
39004 Santander, Spain*presenting author: carmen.hernandez@ieo.es

Age and growth of four-spot megrim (Lepidorhombus boscii) on the Porcupine Bank, a relevant
European fishing area for the demersal fleet, is estimated based on the analysis of otolith (sagittae)
annuli. The state of the stock in Celtic Seas (including Porcupine Bank) and northern Bay of Biscay,
has not been assessed in ICES so far, and biological information for a forthcoming stock
assessment process is required. In this study, the age was estimated by counting translucent bands(annuli) of the sagittal otoliths following internationally standardized protocols. Otoliths wereobtained from specimens caught in five annual bottom trawl surveys (2008-2012) carried out in
Porcupine Bank.
The consistency of the age interpretation of L. boscii is demonstrated by analyzing the regularityof the distances of the (supposed) annuli to the otolith primordium and by the back-calculation of
the annuli. The growth patterns obtained from direct otolith age estimation and from backcalculation are also compared.
The age estimation is corroborated by tracking year-class abundance indices from the surveys. The
strength of the year-classes was well tracked in the first abundant age groups, highlighting thevery abundant 2008 year-class.
Furthermore, the von Bertalanffy growth parameters are also estimated and compared with thosefrom other stocks. The parameters obtained here are available for the upcoming analytical stock
estimation.

Session: Fisheries Ecology and Management120

5th International Sclerochronology Conference, ISC 2019

Northeast Atlantic chub mackerel (Scomber colias): growth
pattern and age validation in Northern Iberian waters
María Rosario Navarro1, Jorge Landa1, Begoña Villamor1, Carmen Hernández1*,
Rosario Domínguez2
1

Instituto Español de Oceanografía (IEO), C.O. Santander, Promontorio de San Martín s/n, 39004 Santander,
Spain
2
Instituto Español de Oceanografía (IEO), C.O. Vigo, Subida a Radio Faro, 50, 36390 Vigo, Spain*presenting author: carmen.hernandez@ieo.es

During the last years, chub mackerel has increased its abundance at its northernmost distribution
limit (Northern Iberian waters), possibly influenced by oceanographic shifts, with potential impact
on other important pelagic fisheries and the ecosystem. Fishery advice has been recently
recommended within ICES to be performed in the near future. Based in samples from commercial
catches and scientific surveys between 2011 and 2017, this study shows the growth pattern andparamenters of chub mackerel in Northern Iberian waters. Absolute and relative otolith marginalincrement analyses and otolith edge nature analysis, based on speciemens from two consecutive
years, are performed to validate the periodicity of growth increments of this population. With the
purpose of corroborating the growth pattern, length-frequency analyses are also peformed. In
addition, the consistency of the age interpretation is tested by the regularity of the otoliths
increments formation and with back-calculation analysis. The growth parameters obtained fromdirect age estimation and back-calculation are also compared between them and with those fromother areas. Our parameters could be used as input in fisheries assessment models.

Session: Growth, Bioenergetics and Ecosystems

121

5th International Sclerochronology Conference, ISC 2019

Automation of bivalve microstructure analysis: Making a
new proxy feasible
Nils Höche1*, Eric O. Walliser1, Melita Peharda2, Bernd R. Schöne112University of Mainz, Institute of Geosciences, Joh.-J.-Becher-Weg 21, 55128 Mainz, Germany
Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia*presenting author: nhoeche@uni-mainz.de

As recently demonstrated, shell microstructure properties can potentially serve as a proxy forambient water temperature. For example, Cerastoderma edule forms larger and more elongatedbiomineral units (BMUs) in warmer waters. Before this method can be broadly applied, it needs tobe validated in different species with the same microstructure and tested for different
microstructures and environments. Furthermore, some analytical challenges require attention: (1)Proper etching techniques are needed for unequivocal BMU recognition; (2) Image analysis iscurrently done in only two dimensions, whereas BMUs are three-dimensional objects; (3)Algorithms are required that can faithfully recognize BMU outlines without manual correction.
Here, we present preliminary results from Glycymeris spp. (Croatia) and Arctica islandica (Iceland
and Baltic Sea) for homogenous, crossed-acicular and crossed-lamellar microstructures.
Best results to study BMUs of homogeneous microstructures were achieved by gently etchingpolished cross-sections under constant stirring for 2h in 0.0001vol% formic acid. Crossed-acicular
microstructures required shorter immersion and higher concentration, i.e., 20s in 0.5vol% formic
acid. Crossed-lamellar microstructures turned out best when oxidized for 30m in 3.5% H2O2.
Subsequent O2-plasma-etching removed superfluous organics and improved image quality.
SEM micrographs were automatically processed and analyzed with ImageJ. Preprocessing withsuitable filters removes noise (median filter) and sharpens BMU contours (Laplacian filter). To
quantify BMU properties, the use of an automatic mean threshold combined with a distancetransform watershed algorithm performed best. Bias induced by differing cutting angles wascounteracted by considering only the sample surface and the 10% largest BMUs. Furthermore,
only lamellae cut perpendicular to their longest axis were analyzed in crossed-lamellar andcrossed-acicular microstructures. Microstructures of the hinge plate of A. islandica (cross-acicular,fine complex crossed-lamellar) offered more numerous morphometric features suitable foranalysis than the homogenous microstructure of the outer shell layer.
In agreement with the seasonal temperature ranges, BMUs of A. islandica from Iceland showed
considerably lower variability in size and shape than specimens from the Baltic Sea.
The new methods hold great promise to reliably and automatically generate morphometric BMU
data in short time, which is crucial to further calibrate and establish the new microstructure-based
temperature proxy.

Session: Proxy Development: Challenges and Opportunities122

5th International Sclerochronology Conference, ISC 2019

Mapping and quantification of sub-annual trace element
variation in otoliths of toothfish (Dissostichus eleginoides)
using µXRF and LA-ICP-MS
Phil Hollyman1,2, Simon Chenery2*
12

British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
Centre for Environmental Geochemistry, British Geological Survey, Nottingham NG12 5GG, UK*presenting author: srch@bgs.ac.uk

Trace element concentrations within fish otoliths can be used as proxies for reconstructing several
aspects of environmental and ecological histories. The efficacy of these proxies varies acrossspecies groups and environmental contexts but with appropriate validation, they remain apowerful tool for retrospective studies. The Patagonian toothfish (Dissostichus eleginoides)
supports several fisheries in Southern latitudes, notably around the island of South Georgia, which
has a fishery that is widely acknowledged as well managed and sustainable. Due to their longevity,
otoliths from South Georgia toothfish toothfish have the potential to contain long time series of
elemental information of up to 60 years, roughly 3x longer than existing in-situ environmental
datasets from the same location. Whilst micro-chemistry of D. eleginoides otoliths has been
undertaken in the past, this has been for the purpose of stock discrimination and until now, no
sub-annual or full growth axis analysis has been performed. This poster will outline the findings
from an exploratory LA-ICP-MS and synchrotron µXRF study to identify potential proxies andinvestigate spatial distributions of trace elements contained within these otoliths. Distinct annual
cycles in key trace elements (e.g. Sr) were observed along with clear ontogenetic changes in traceelement incorporation. These findings are being developed to answer important fisheries related
and ecological questions. These include the timing of ontogenetic depth migrations, the timing
and drivers of growth line formation and the timing of apparent pre-maturation migrations to theSouth Sandwich Islands, an archipelago roughly 550 km East of South Georgia. This project will
form a basis of understanding, allowing us to approach these key life history questions andimprove the long-term management of this species.

Session: Fisheries Ecology and Management

1235th International Sclerochronology Conference, ISC 2019

Using anually-resolved bivalve records and biogeochemical
models to understand and predict climate impacts in coastal
oceansSarah Holmes1*, Paul Halloran1, Paul Butler1, Johan van der Molen2, John
Aldridge3, Chris Perry11Department of Geography, University of Exeter, UK
Royal Netherlands Institute for Sea Research (NIOZ), Netherlands
3
Center for Environment, Fisheries and Aquaculture Science (CEFAS), UK
2*presenting author: s.holmes@exeter.ac.uk

Projected to warm at substantially greater rates than those in the open ocean, the shelf seas are
extremely vulnerable to the effects of climate change. These highly productive coastal ecosystems
are therefore of great socio-economic significance and understanding how they will change in the
future is of major importance to decision-makers. However, attempts to do so are hindered byinsufficient observational data. Long-term, highly spatially- and temporally-resolved datasets ofthe marine environment simply do not exist.
Simulating the shelf seas with biogeochemical models can provide valuable data and huge efforts
across the modelling community are invested into developing and increasing the reliability ofthese models. However, in the current state of knowledge, these are typically validated using (atbest) the aforementioned sparse observational datasets, and often against climatologicalobservational fields. With increasing pressures on coastal ecosystem services, we need to do
better. For the first time, this research is attempting to assess model skill with the use of marine
proxies. Of all marine proxies available, sclerochronology (the study of the growth bands on longlived marine clams) is the only one (at mid-to-high latitudes) that provides absolutely-dated, multicentennial, annually-resolved archives of past ocean environment, analogous todendrochronology in terrestrial environments.
This PhD project is attempting to demonstrate the benefits of proxy-model fusion by combining
the European Regional Seas Ecosystem Model (ERSEM) with the sclerochronologies of bivalve
molluscs (clams) Glycymeris glycymeris and Arctica islandica on the North West European Shelf(NWES). The research aims to better parameterise the “filter feeder” component of ERSEM (using
1D hindcasts) and give insight into the factors controlling bivalve growth in order to betterinterpret these proxy records. A key finding has been that by controlling meteorological inputs
into the model, we can mechanistically attribute bivalve growth variability to wind speed
variability. This novel research will contribute to a better understanding of the NWES sea
environment with potential to improve predictions of future climate change in this region andbeyond.

Session: Climate and Oceans: Past, Present and Future124

5th International Sclerochronology Conference, ISC 2019

Extracting seasonality signals from Late Albian bivalve shells:
A multiproxy multispecies approach
Stefan Huck1*, Niels de Winter2, Rute Coimbra3, Philippe Claeys2, Ulrich
Heimhofer11Institut für Geologie, Leibniz Universität Hannover, Germany
AMGC research group, Free University of Brussels (VUB), Brussels, Belgium
3
3GeoBioTec, Dpt. of Geosciences, University of Aveiro, Portugal and MARE, Earth Sciences Dpt., University of
Coimbra, Portugal
2*presenting author: huck@geowi.uni-hannover.deCretaceous rudist bivalve shells have been shown to faithfully record inverse cyclic changes ofoxygen isotope ratios and Mg contents, which are interpreted to represent seasonal temperaturechanges of the ambient sea water (Steuber, 1999). Estimating the impact of salinity changes on
the rudist shell oxygen isotope composition at a given setting, however, is still problematic andcalls for a calibration of oxygen-isotope based sea surface temperatures by means of additionalpalaeothermometers (e.g. clumped isotopes or TEX86). Moreover, a metabolic control on theisotopic composition of the low-Mg calcite rudist shell cannot be completely ruled out, as nomodern analogues of these extinct bivalves exist.
In order to disentangle the influence of palaeoenvironment, diagenesis and ‘vital effects’ on the
rudist shell geochemistry, the current study compares highly resolved multi-proxy (stable
isotopes, trace elements) sclerochronological records of different Late Albian bivalve taxa
(requieniid and radiolitid rudists, pectinids, chondrodonts and oysters) derived from the same
proto-North Atlantic palaeoenvironmental setting in Portugal (Lusitanian Basin, Horikx et al.,2014). In contrast to classical methods such as ICP-OES, the here applied micro-XRF scanningtechnique allows to simultaneously measure a variety of elements, which help to (i) distinguishbetween natural and diagenetic enrichments of indicative elements such as iron and manganeseand to (ii) identify the influence of palaeoenvironmental changes (SST, nutrients, salinity etc.) onbivalve shell growth (see de Winter et al., 2017). A multivariate statistical approach is presented
to identify the influence of differential diagenesis on these multi-proxy records.
In particular, the comparison of rudist and pectinid sclerochronological records is a very promising
approach, as pectinids have living analogues and therefore much more is known about the
metabolic control on the shell geochemistry. This in turn will help to better understand thepalaeoecology of rudist bivalves and how these animals recorded palaeoceanographic signals intheir shells.
Referencesde Winter, N.J. et al. (2017) Palaeogeography, Palaeoclimatology, Palaeoecology, 485, 740-760.
Horikx, M. et al. (2014). Newsletters on Stratigraphy, 47, 85-106.
Steuber, T. (1999) International Journal of Earth Sciences, 88, 551-570.

Session: Proxy Development: Challenges and Opportunities

125

5th International Sclerochronology Conference, ISC 2019

Recent ENSO Evidence from Fiji: Climate Archives inMiddens (REEFCLAM)
Eleanor H. John1*, Elia Nakoro2
1
2

School of Earth and Ocean Sciences, Cardiff University, Park Place, Cardiff CF10 3AT, UK
Fiji Museum, Suva, Fiji*presenting author: johne11@cardiff.ac.uk

Giant clam shells are highly valuable archives of past climate data: they are fast-growing, longlived, and their dense shells have annual growth bands that can be subsampled and analysed to
produce sub-annually resolved climate proxy records spanning multiple decades. Moreover, they
are common in the tropical Pacific, where paleoclimate data is particularly valued as sub-annual
to decadal-scale changes in this region have been linked to dramatic global temperature andrainfall anomalies with far-reaching socioeconomic and environmental effects. The challenge inusing them is finding material of suitable age and quality to investigate pre-industrial climate
variability. Giant clams have been (and are) a common food and tool supply in the tropical Pacificand are abundant in Lapita-age (~3500–2500 cal BP) shell middens, providing unique opportunities
for paleoclimate research that have not yet been exploited. I plan to use shells from a Lapita-age
shell midden in southwest Viti Levu, Fiji, to generate the first pre-industrial Tridacna-based recordof climate variability in Fiji. This will provide a snapshot of past seasonal to decadal variability insea surface temperature and salinity in an important yet understudied region and test the
hypothesis that the first major pulse of eastward human migration into the Pacific by the Lapita
people was associated with an interval of more frequent El Niño events.

Session: Climate and Oceans: Past, Present and Futuere126

5th International Sclerochronology Conference, ISC 2019

Microgrowth-increment and isotopic data from subthermocline Aequipecten opercularis: recognition of setting
and fidelity of temperature records
Andrew L.A. Johnson1*, Melita Peharda2, Bernd R. Schöne3, Ivica Janeković4,
Annemarie Valentine5
1

School of Environmental Sciences, University of Derby, Derby DE22 1GB, UK
Institute of Oceanography and Fisheries, 21000 Split, Croatia
3
Institute of Geosciences, University of Mainz, 55128 Mainz, Germany
4
UWA Oceans Institute, University of Western Australia, Crawley, WA 6009, Australia
5
School of Geography and Environmental Science, Nottingham Trent University, Southwell NG25 0QF, UK
2*presenting author: A.L.A.Johnson@derby.ac.uk

The shell δ18O of benthic marine molluscs is commonly an accurate reflection of seafloor
temperature. Ontogenetic profiles from organisms that lived in continuously well-mixed settings
can be read as a record of surface temperature but those from depths below the summer
thermocline cannot: the maximum benthic temperature recorded will always be less than thesurface temperature. For the purposes of interpreting palaeoclimate (i.e. surface temperature)from the δ18O of fossil shells it is important to be able to tell whether the organism lived in a supraor sub-thermocline setting and, if the latter, whether even benthic temperature is accurately
represented. We investigated ontogenetic variation in δ18Oshell, δ13Cshell and microgrowthincrement size in three modern specimens of the pectinid bivalve Aequipecten opercularis,collected live on 13thSeptember 2016 from a seasonally stratified setting (38 m depth) in thenorthern Adriatic Sea. Fluctuations in δ18O (undoubtedly due to seasonal temperature variation)
indicate that two shells started post-larval life in winter 2013-14 and one in winter 2014-15. Shell
δ13C does not parallel δ18O, contradicting a model for variation of this parameter in seasonallystratified settings (Arthur et al. 1983; Geology 11:655-659), but microgrowth-increment sizeshows substantial seasonal variation (out of phase with δ18O) in two of the shells, in accordancewith a model for this parameter (Johnson et al. 2009; Palaeogeography, Palaeoclimatology,
Palaeoecology 284:164-179). The δ18O of material apparently deposited during winter 2013-14,
summer 2014 and winter 2014-15 in general closely matches predicted values based on modelledtemperatures and salinities (hence water δ18O) for the location, depth and interval. However, theminimum shell δ18O values (corresponding to the warmest temperatures) recorded during
summer 2015 are substantially above the values predicted for this unusually warm summer, whenbenthic temperature reached 23°C. Temperatures approaching this are recorded in the shell δ18O
of A. opercularis from elsewhere in the Mediterranean (Malaga area and Gulf of Tunis). Theirabsence for summer 2015 in northern Adriatic shells probably reflects cessation of growth, notdue to high benthic temperature but perhaps because of low oxygen availability associated witha stable (stratified) water column and high benthic respiration. Physical evidence of growth
cessation in summer 2015 is scant so while sub-thermocline examples of A. opercularis can be
identified (from microgrowth-increment data) and provide a faithful isotopic record of benthic
temperature in winters and some summers, extremely warm summers are neither recorded nor
suggested.

Session: Proxy Development: Challenges and Opportunities

127

5th International Sclerochronology Conference, ISC 2019

Understanding growth variation and life history diversity in a
migratory salmon population using otolith microstructuraland microchemical analysis
Brian P. Kennedy1,2*, Jensen Hegg1, Katherine Gilles-Rector1
12

Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho 83844-1136, USA
Department of Biology and Geology, University of Idaho, Moscow, Idaho 83844-1136, USA*presenting author: kennedy@uidaho.edu

Understanding the conditions that create and maintain a portfolio of salmon migration strategies
is challenging in large river systems where life history diversity can be the product of many factors.
Here, we paired a long-term otolith dataset of life history expression with a bioenergetic analysis
of early growth opportunity in a salmon population to identify how growth conditions related tolife history expression for individual fish for which we isotopically reconstructed migratory paths.
In the Snake River, Idaho, USA, populations of fall Chinook salmon (Oncorhynchus tshawytscha),appear to be exhibiting novel life history strategies in response to the widespread alteration ofmainstem migratory corridors. Using otolith microchemistry and microstructure analysis, we havestudied spatially-explicit variation in migratory timing and its implications for how water resources
are stored and managed throughout the Columbia River system. Our laboratory has explored theapplication of novel data acquisition techniques, such as Laser Ablation Split Stream ICPMS, as well
as data analysis methods, such as Dynamic Time Warping, to optimize the resolution and efficiencyof our life history reconstructions. Our combined bioenergetics and life history analyses havedemonstrated differences in mainstem reservoir use and early life history growth that are based
upon natal rearing locations as well as annual differences in climate. Specifically, our findings
indicate that delayed migration of some individuals is correlated with larger sizes at ocean entry,
but that this strategy is not expressed evenly across the species’ distribution. In source habitats
where delayed migration is more common, its prevalence in any given year is significantly affectedby annual variation of flow in the basin. Our long-term dataset has improved our understandingof the selection for migratory timing across an altered landscape and its implications for
population resilience.

Session: Fisheries Ecology and Management128

5th International Sclerochronology Conference, ISC 2019

Giant clam growth in the Gulf of Aqaba is accelerated
compared to fossil populations: The role of nitrate aerosol
fertilization
Daniel Killam1*, Tariq Al-Najjar2, Matthew Clapham3
1

University of Haifa, Department of Marine Geosciences, Israel
University of Jordan, Aqaba Branch, Jordan
3
University of California, Santa Cruz; Department of Earth and Planetary Sciences, USA
2*presenting author: daniel.e.killam@gmail.com

The giant clams are globally distributed reef-dwelling bivalves which use the same photosymbiotic
partnership characteristic of reef-building corals. But while the declining health of corals in theface of climate change and human pollution are the topic of intensive research, comparatively
little work has been dedicated to understanding trends in the health of giant clams in relation toenvironmental change. We have collected fossil and modern specimens of three species of
Tridacna from reefs fringing the Gulf of Aqaba in the Northern Red Sea. After calibrating thedaily/twice-daily growth bands from the outer layer of their shells, we have determined that all
three species are growing more quickly in the modern day compared to fossil specimens from
Holocene and Pleistocene reefs. We found that giant clam shell organic δ15N of modern specimensshow a 4.5‰ lower average value compared to fossil specimens, an offset which we propose ismost likely attributable to increased deposition of isotopically light nitrate aerosols in the modern
era. As nitrate is a known accelerant of giant clam growth, it may play a role in the faster growthseen in modern populations. We found that that growth is positively correlated to temperature asmeasured by oxygen isotope paleothermometry of their shell carbonate, and discuss how lower
winter cold temperatures in the past may have depressed giant clam growth compared to therelatively small seasonal availability seen today. Giant clams can serve as isotopic and physiologicalsentinels of reef environmental change, both to determine their own comparative health and thatof the coral reefs they inhabit.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

1295th International Sclerochronology Conference, ISC 2019

Dramatic growth anomalies and isotopic disequilibrium
characterize the shell portion of oysters formed during thejuvenile period
Damien Huyghe1,2, Marc de Rafelis3, Mathieu Daëron4, Laurent Emmanuel5,
Vincent Mouchi5, Michel Ropert6, Nathalie Labourdette5, Maurice Renard5,
Franck Lartaud1*
1

Sorbonne Université, CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques, LECOB, Observatoire
Océanologique de Banyuls, F-66650 Banyuls-sur-mer, France
2
Centre de Géosciences, MINES Paris tech, PSL University, 35 rue St Honoré, 77305 Fontainebleau cedex, France
3
Géosciences Environnement Toulouse, UMR 5563 CNRS, UR 234 IRD, UM 97 UPS, Observatoire Midi-Pyrénées,
CNES, 14 avenue Edouard Belin, 31400 Toulouse, France
4
Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-USVQ, Université Paris-Saclay,
Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex, France
5
Sorbonne Université, CNRS-INSU, Institut des Sciences de la Terre Paris, ISTeP, F-75005 Paris, France
6
Ifremer, Laboratoire Environnement Ressource de Normandie, Avenue du Général de Gaulle, BP 21, 14520
Port-en-Bessin, France*presenting author: franck.lartaud@obs-banyuls.fr

Biomaterials are now widely used as an archive of past and present environmental conditions. The
development of sclerochronology and sclerochemistry provides clues in the characterization of both
long-term and high frequency environmental changes (e.g., infra-seasonal). But in many cases,
interpretations are limited by the metabolism impact on growth increment formation and thegeochemical signal they hold. To solve this limitation, a multi-proxy approach can be useful together
with a better insight into skeleton growth processes, particularly at high-resolution. The lack of achronological constraint in the accretion of hard tissues is a major obstacle for the use of proxy, whichneeds to be clearly defined for each studied species.
Based on monthly mark and recapture techniques applied in the field over two years, we conducted
an insightful study on oyster shell growth and the potential use of isotopic proxies (oxygen stable
isotopes and clumped-isotopes). The cathodoluminescence microscopy of shells previously stainedwith manganese reveals two distinct patterns depending on the age of the organism. After one year
old (i.e., reaching the sexual maturity), the formation of growth increments follows a tide-related
model, leading to the mineralization of ~2 incr. per day. Also, growth rate changes at lunar and semilunar periodicities are recorded during this period, as well as a seasonal trend interrupted by growth
breaks when temperature decreases below 6°C. But in the shell portion younger than one year old,
although the general growth rate is higher, growth increments analysis reveals unconventional
patterns. We observe either up to five growth increments formed per day or less than one yet large
increment per day, associated with frequent growth cessations. These juvenile patterns haveconsiderable consequences on the use of isotopic proxies. Although oxygen stable isotopes (δ 18O) andclumped-isotopes (∆47) match well with the seasonal trend during most part of the shell mineralization(i.e., oysters aged of ≥ 1 year old), during the juvenile period (i.e., < 1 year old), both δ 18O and ∆47areout of isotopic equilibrium. For these two proxies, the estimated temperatures are ~10°C higher
compared to the environmental monitoring, likely related to kinetic effects in the incorporation of
isotopes. We thus recommend to carefully consider this potential bias during the juvenile
mineralization prior to use biomaterials as (paleo)environmental archive from geochemical proxies.

Session: Proxy Development: Challenges and Opportunities
1305th International Sclerochronology Conference, ISC 2019

A multi-decade record of increasing growth rates in a Mid
Atlantic population of ocean quahogs
Matthew Long1*, Sara Pace2, Roger Mann1, Eric Powell2, Theresa Redmond1
1

Virginia Institute of Marine Science, Gloucester Point, VA 23062 USA
Gulf Coast Research Laboratory, University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS
39564; USA
2*presenting author: mclong@vims.edu

The Mid Atlantic continental shelf of the United States east coast is a highly productive region forcommercially important fish and shellfish species. A cold pool of water persists below an intense
seasonal thermocline in this region with annual water temperature ranges more reflective of
higher, boreal latitudes. An extensive population of the ocean quahog, Arctica islandica (Linnaeus
1767), occurs throughout the bathymetry of this cold pool region. Large ocean quahogs (>100mm
shell length) collected from this region have recently been demonstrated to exhibit increased
growth rates over two centuries from 1775 to 1975. An examination of growth increments for acollection of immature and small mature ocean quahogs from the same location provided
evidence of a continued trend of increasing growth rates between 1975 and the present.
Examination of growth in immature animals required the development of methods, describedherein, to address the unique challenges posed by erosive loss of early growth lines in the outershell material of ocean quahogs; specifically, for estimation of missing or incomplete internal
growth lines in other hard-shelled marine organisms. Application of this approach demonstrated
an acceleration of the increase in growth rate within the most recent decade.

Session: Climate and Oceans: Past, Present and Future131

5th International Sclerochronology Conference, ISC 2019

Otolith morphometry relations of Trachurus picturatus(Bowdich, 1825) from two different areas: the CanaryIslands and the Ligurian-Northern Tyrrhenian Seas
Alba Jurado-Ruzafa1, Andrea Massaro2*, Alessandro Ligas3, María Teresa García
Santamaría1
1

Spanish Oceanographic Institute (IEO), Canary Oceanographic Centre, Vía Espaldón, Dársena Pesquera 8,
38180, Santa Cruz de Tenerife, Spain
2
APLYSIA, via Menichetti 35, 57121, Livorno, Italy
3
CIBM, viale Nazario Sauro 4, 57128, Livorno, Italy*presenting author: andrea.massaro@aplysia.it

Relationships between otolith morphometry and fish size of Trachurus picturatus (Bowdich, 1825)
from the Canary Islands (CI, CE Atlantic) and the Ligurian-Northern Tyrrhenian Seas (LNT,
Mediterranean Sea) were investigated. The blue jack mackerel is a benthopelagic species
occurring from the Bay of Biscay to Mauritania (including Azores and the Canary Islands), and in
the Mediterranean. In the CI, this species is caught exclusively by the artisanal purse-seine fleet
and represents the second-most important species of small pelagic fish in terms of landings,
accounting for approximately 700 tonnes in 2017. In LNT, this species is landed together with T.
trachurus and T. mediterraneus, therefore it is not possible to gather accurate estimates of theirlandings. Anyway, the abundance of blue jack mackerel is lower than the other two species.
A total of 153 specimens were collected: 58 individuals from LNT, ranging from 8.0 to 42.5 cm total
length (TL) and 95 individuals from CI (10.4-40.5 cm TL). The analysis of covariance (ANCOVA) wasused to test the effect of the categorical factor area in the fish length-weight relationship, in therelationship between fish TL and otolith length, and in the otolith morphometric relationships (i.e.
length, width, radius, perimeter). The factor splits the relationship between dependent andindependent variables into two equations (one for each area). Regression lines were compared bystudying the interaction of the factor with the independent variable. If the interaction issignificantly different from zero, the regression lines have different slopes, thus there is significant
difference between the two areas.
The results of the analyses showed no significant effect of the factor area in the fish length-weight
relationship. In contrast, significant differences were found in the otolith morphometric
relationships due to the effect of the factor area, supporting the hypothesis of a possible
segregation between Atlantic and Mediterranean populations of the blue jack mackerel.

Session: Fisheries Ecology and Management1325th International Sclerochronology Conference, ISC 2019

Inferring the population dynamic from otolith phenotypes
Alba Jurado-Ruzafa1, Víctor Manuel Tuset2, José Luis Otero-Ferrer3, Andrea
Massaro4*, María Teresa G. Santamaría1
1

Spanish Oceanographic Institute (IEO), Canary Oceanographic Centre, Vía Espaldón, Dársena Pesquera 8(38180), Santa Cruz de Tenerife, Spain
2
Institute of Marine Sciences (CSIC), Department of Renewable Resource, Passeig Marítim 37-49 (08003),
Barcelona, Spain
3
University of Vigo, Departament of Ecology and Animal Biology, Fonte das Abelleiras (36310), Vigo, Spain
4
APLYSIA, via Menichetti 35 (57121), Livorno, Italy*presenting author: andrea.massaro@aplysia.it

The polymorphism is commonly unexplored in studies on fish dynamic population despite its
relationship with the life histories and spatial distributions. Considering the phenotypic variabilityof otolith contour, we provide a new perspective on the population of Trachurus picturatus(Bowdich, 1825) inhabiting the Canary Islands (eastern central Atlantic Ocean). Our findings
revealed the presence of three otolith phenotypes (M1, M2 and M3) in similar proportions, which
are not linked to sex, age and fish size. They showed temporal variations associated to life cycle:
spawning, recruitment and feeding. The best model to explain this population structure could be
the “contingency theory” where a population is composed by migrants and residents. In addition,
each fish group showed significant differences in the Von Bertalanffy growth parameters. Bothresults revealed that the insular population of the Canary Islands would be more complex than apriori was expected.

Session: Fisheries Ecology and Management1335th International Sclerochronology Conference, ISC 2019

Fish and sclerochronology research in the Mediterranean –challengies and opportunities
Sanja Matić-Skoko1*, Melita Peharda1, Dario Vrdoljak1, Hana Uvanović1,
Krešimir Markulin1
1

Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia*presenting author: sanja@izor.hr

Over the past two decades, field of sclerochronology has been rapidly developing and scientists
are devoting significant efforts studying physical and chemical variations in hard tissues ofdifferent marine organisms. Most of this research has been limited to certain taxa and geographic
areas. Although growth increments in fish otoliths are being used for sclerochronological
purposes, very little has been done in the Mediterranean Sea. The main reasons include following:(i) the longevity of very few fish species in the Mediterranean Sea extends over several decades,(ii) there are almost no otolith samples available prior to 1950s, (iii) there are problems associatedwith reliable age determination for certain long-lived fish species (e.g. Sparidae, Scorpaenidae,
Serranidae), (iv) efforts to model the impact of climate change on fish growth have been hampered
by a lack of long-term (multidecadal) data needed to understand the effects of temperature on
growth rates in natural environments and (v) funding, expertise and instrumentation is limited.
Despite these challenges, fish sclerochronology research does have the potential in the
Mediterranean, and adjacent Seas. Recent studies in the Adriatic Sea resulted in construction ofbivalve chronologies as well as geochemical analysis of shells and provide important time-series
data for comparative analysis and multispecies approach. Furthermore, studies conducted inother parts of the world have demonstrated potential for use fish otolith as monitors ofenvironmental variability and the effects of pollutants and disturbance. In a framework of NURSE
fish project, financed by the Croatian Science Foundation, we recently started geochemical
analysis of otoliths from Sparidae family and are investigating ways and possibilities for developing
this line of research at the Institute of Oceanography and Fisheries in Split.

Session: Fisheries Ecology and Management1345th International Sclerochronology Conference, ISC 2019

An otolith biochronology provides evidence for species
interactions in the Aleutian Islands ecosystem
Mary Elizabeth Matta1*, Kimberly Rand2, Morgan Arrington3, Bryan Black4
1

Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric
Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA
2
Lynker Technologies, LLC, 202 Church Street SE #536, Leesburg, VA 20175, USA
3
School of Aquatic and Fishery Sciences, University of Washington, 1122 NE Boat Street, Seattle, WA 98105, USA
4
Laboratory of Tree-Ring Research, University of Arizona, 1215 E Lowell Street, Tucson, AZ 85721-0045, USA*presenting author: beth.matta@noaa.gov

Fish otolith increment chronologies developed using mixed effects models can reveal factors
contributing to growth. These annually resolved, multi-decadal chronologies have been used to
identify temporal and spatial patterns in growth variability. Here, we used a mixed modelingapproach to determine the relative importance of intrinsic factors (e.g., sex, age) and extrinsic
factors (e.g., temperature, abundance of con-specifics and competitors) to growth of Atka
mackerel, a commercially important groundfish dominant in the Aleutian Islands ecosystem. A
yearly alternating pattern of wide and narrow increments was observed, and was negatively
correlated with abundance of pink salmon, suggesting possible competition over shared foodresources such as copepods (which were positively correlated with the otolith chronology). We
also contrast the otolith chronology with a body condition index to examine the relationshipbetween otolith and somatic growth.

Session: Fisheries Ecology and Management

1355th International Sclerochronology Conference, ISC 2019

Depth-dependent environmental factors control Arctica
islandica shell growth variability in SW Iceland
Madelyn Mette1*, Fabian Bonitz1, Paul Halloran2, Vilde Melvik1, Tamara
Trofimova1, Carin Andersson1
1
2

Norwegian Research Centre, Bjerknes Centre for Climate Research, Bergen, Norway
Department of Geography, University of Exeter, Exeter, United Kingdom*presenting author: mame@norceresearch.no

Cross-dated sclerochronologies are the foundation of absolutely dated, annually resolved proxyreconstructions using growth and geochemical measurements of bivalve shells. Synchronous shell
growth patterns indicate the presence of a common environmental forcing, however, it is notalways possible to determine the combination of factors controlling shell growth in different
settings due to limited environmental data. The present study investigates differences between
shell growth chronologies from two sites, one at 50m depth and one at 100 m depth, located 50
km apart in Flaxafloi, SW Iceland. Instrumental and model data reveal significant differences in theannual temperature cycle and thermocline dynamics between the two study sites. Hypotheses will
be presented to explain the prevalent environmental forcings at each site and their resulting
influences on shell records.

Session: Climate and Oceans: Past, Present and Future136

5th International Sclerochronology Conference, ISC 2019

Determination of age and growth in fish of the Pacificpomfret (Brama australis) in south central and southern off
Chile
Guillermo Moyano1*
1

Instituto de Fomento Pesquero, Calle Blanco 839, Valparaíso, Chile*presenting author: guillermo.moyano@ifop.cl

The main life history parameters of the Pacific pomfret (Brama australis) of samples from theindustrial (trawl) and artisanal vessels (longline and gillnet) that operate in south-central andsouthern off Chile (35°00'S and 57°16'S) during the period 2012 to 2016, represented byindividuals between 25.0 to 58.0 cm fork length (FL). The growth parameters were obtained fromthe annuli reading in sagittal otoliths, where the location of the first annulus was verified throughdaily microincrements analysis. The highest growth rates occurred during the first year of life,
reaching a size of 30.13 cm FL at a daily rate of 0.55 mm*day-1. The catches of the different fishinggears were mostly represented by individuals of 4 years of age. The average length of sexual
maturity (L50%), corresponding to 37.7 cm FL was reached at age 3. Finally, otolith shape indexes
analisys showed 3 different morpho-types, which are not associated with capture zones, fishinggears, sex or length of the individual

Session: Growth, Bioenergetics and Ecosystems

137

5th International Sclerochronology Conference, ISC 2019

Stereoscopic vision of otoliths by microphotogrammetry
Lizandro Muñoz1*, Luis Cid1
1

Instituto de Fomento Pesquero, Blanco 839, Valparaíso, Chile*presenting author: lizandro.munoz@ifop.cl

Microphotogrammetry of otoliths is a technique that consists of obtaining 3D models from 2D
images, which considerably broadens the possibilities of morphometric studies of otoliths invarious fishing resources with specific applications such as stock differentiation among others. It
is possible through the sequential acquisition of images to obtain digital reconstructions in three
dimensions. The objective of this work is to develop a working methodology for obtaining otoliths
images 3d with materials and tools available in the age and growth laboratory of the Instituto de
Fomento Pesquero and that can be replicated in other laboratories. Otoliths of some of the main
species that make up the commercial fisheries of Chile were used, as well as an image analysis
device with Image Pro Premier, Agisoft, VSCD softwares and an adjustable speed cutting machine.
By means of this procedure, several measurements can be obtained in both two-dimensional andthree-dimensional planes that can be used in various inter and intraspecific characterization
studies. As a final result three-dimensional images of otoliths are obtained that offer possibilities
for further studies, mainly of morphometric characterization and species differentiation.

Session: Growth, Bioenergetics and Ecosystems

138

5th International Sclerochronology Conference, ISC 2019

The trace element composition of mussel shells reflected thetsunami-induced environmental changes inherent inindividual bays
Naoko Murakami-Sugihara1*, Kotaro Shirai1, Hiroshi Ogawa1
1

Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan*presenting author: nsugihara@aori.u-tokyo.ac.jp

Coastal zones are one of the most important habitats for organisms, but vulnerable to be natural
disasters or manmade event. On 11 March 2011, the eastern coast of Japan was seriously
damaged by a massive tsunami following the 2011 Tohoku Earthquake. This devastating tsunami
altered the coastal ecosystems and biogeochemical cycles. To accurately understand the impact
of such natural disaster on the coastal environment, continuous environmental information frombefore to after the event is essential. However, data before the event is often lacking and fieldobservations are also difficult during and immediately after such event.
High-resolution reconstruction of the past environment using biological hard tissues, such asbivalve shells, is a promising method for solving such a problem. During their growth, bivalve shellgeochemical compositions reflect the external environment. Here we investigated the impact of
the tsunami on the coastal environment based on trace element analysis of mussel shells. On
September 2011, Mediterranean mussels (Mytilus galloprovincialis) were collected alive fromseven intertidal locations along the northeastern Pacific coast from Iwate to Fukushima. Shells
were cut along the maximum growth axis. Trace element compositions on the polished shell crosssection were analyzed along the growth direction using LA-ICP-MS. Prior to this study, Sugihara etal. (in review) analyzed trace element composition of a mussel shell from the Otsuchi Bay. We
found that changes in oxygen isotopic ratio was synchronous with the shell Mg/Ca ratio, indicating
seasonal cycles. We also revealed that the shell Mn/Ca ratio rapidly increased just after thetsunami, of which age model was established by growth line counting. Increased shell Mn/Ca ratio
just after the tsunami was likely attributed to suspended terrestrial soil and seafloor sediment in
the water column caused by the huge tsunami waves. In this study, five more locations wereadditionally investigated. Mn/Ca ratios were increased at the timing when Mg/Ca decreased at
the timing of the tsunami occurred (winter, March). The height and duration of the Mn/Ca peakwere different for each bay. This may be attributed to a different characteristic between the bays,
such as the amount of inflow of terrestrial soils, seawater exchange, and residence time of eachbay.
Session: Environmental Biomonitoring & Entrepreneurship139

5th International Sclerochronology Conference, ISC 2019

Stable isotope study of a Glycymeris glycymeris populationfrom the Iberian Shelf
Alexandra Németh1,2*, Zoltán Kern1,2, Victor Quintino3
1

Isotope Climatology and Environmental Research Centre (ICER), MTA ATOMKI, Debrecen, Hungary
Institute for Geological and Geochemical Research, MTA Research Centre for Astronomy and Earth Sciences,
Budapest, Hungary
3
Department of Biology & CESAM–Research Center Environmental and Marine Research, University of Aveiro,
Aveiro, Portugal
2*presenting author: nemethalexandra89@gmail.com

Glycymeris species have a known potential in reconstructing past seawater temperatures as
several studies have reported that shell aragonite is precipitated in isotopic equilibrium with theambient seawater and most of the seasonal oxygen isotope signature is recorded in the shellcarbonate. The extent of the seasonality these shells can record, however, is still discussed andmost studies focused on collection sites in the Adriatic and the northern temperate regions of theNorth-Atlantic.
The aim of this study was to investigate the driving factors for shell growth in Glycymeris bivalves
by analysing the growth patterns and stable oxygen- and carbon-isotope composition of
Glycymeris glycymeris shells collected from the Atlantic coast of the Iberian Peninsula. Subsets of
the Aveiro (n=10) samples could be arranged into a robust site chronology covering the 1991-2001
period and were used to explore shell growth responses to environmental parameters. The
chronology displayed a positive correlation (r=0.82, p < 0.05) with the regional January-March sea
surface temperature (SST). The results suggest that at this collection site, lower winter SST was a
directly limiting environmental variable. Comparing sub-annually resolved oxygen isotope ratiosfrom three specimens with overlapping lifespans (1984-1993) to satellite-derived temperature
data proved that summer seawater temperature maxima were recorded within the shellcarbonate, whereas annual minima are not reflected.

Session: Proxy Development: Challenges and Opportunities

140

5th International Sclerochronology Conference, ISC 2019

Temperature seasonality as recorded in shell microstructureof genus Scapharca (Mollusca: Bivalvia): new insights into
the age determination and paleoenvironmental study
Kozue Nishida1,2*
12

National Institute of Technology, Ibaraki College, JapanThe Japan Society for the Promotion of Science (JSPS), Japan*presenting author: nishida@gm.ibaraki-ct.ac.jp

Shell microstructures in Bivalvia have been studied predominantly in relation to taxonomy (Taylor,1963; Kobayashi, 1971; Carter, 1990; Sato et al., 2013), phylogeny (Taylor et al., 1969, 1973;
Shimamoto, 1986], and crystallography (Ubukata, 2000, 2001; Checa et al., 2009, 2013). As shownin these studies, some bivalve species crystallize shells with a single constituent mineral whereas
others form a shell composed of both calcite and aragonite (e.g., a calcitic outer prismatic layer
and an aragonitic inner nacreous layer in pearl mussels). Moreover, the shell microstructures
made by a single individual can differ, depending on the environmental conditions it experiences
during biomineralization (Carter, 1980; Nishida et al., 2012).
Cyclical changes in the shell microstructure within a single shell layer have been observed invarious taxa of Bivalvia (Nishida et al., 2011). In family Arcidae, both modern and fossil specimens
in genera Scapharca and Anadara showed the changes (Kobayashi and Kamiya, 1968; Kobayashi,
1976a,b; Nishida et al., 2012; Nishida and Sasaki, 2018). I will present my recent studies of theshell microstructure of genus Scapharca evaluating the relationship between water temperatureand shell microstructural formation by geochemical and culture experimental approaches tocontribute to paleoecological and paleoenvironmental studies.
In genus Scapharca, the outer shell layer of this species is characterized by composite prismatic
structure on the exterior side and crossed lamellar structure on the interior side. By comparing
cyclical microstructural changes of S. broughtonii with the temperature records calculated bystable oxygen isotopes of the shells of field-collected specimens, the relative thickness ofcomposite prismatic structure is greater at cooler temperatures (Nishida et al., 2012; Nishida andSasaki, 2018). Moreover, Nishida et al. (2015) revealed the thermal dependency on shell
microstructural formation by a rigorous culture experiment at the five different temperature
treatments, and this result was consistent with the trend observed in field-collected specimens.
The temperature seasonality in shell microstructure can be applied to age determination and thecharacterization of the summer and winter seasons which helps the milling of shells forgeochemical analysis as same as a soft X-ray observation.

Session: Proxy Development: Challenges and Opportunities

141

5th International Sclerochronology Conference, ISC 2019

Life history patterns of modern and fossil Mercenaria fromthe US Mid Atlantic Coastal Plain during cold vs. warm
climate conditions
Kylie L. Palmer1*, Donna Surge1, David K. Moss2
1
2

University of North Carolina-Chapel Hill, Department of Geological Sciences, Chapel Hill, NC, USA
Sam Houston State University, Department of Geography & Geology, Huntsville, TX, USA*presenting author: kylaine@live.unc.edu

Given the current trend of global warming, the biological consequences of increasing watertemperature on economically and ecologically important bivalves are uncertain. One way to assess
such impacts is to evaluate changes in life history across space and time in the context of warm
vs. cold climate conditions. This assessment can be accomplished using sclerochronlogy. Today,
marine bivalves exhibit a consistent latitudinal pattern in their life history. Bivalves from mid tohigh latitudes tend to grow slower and have longer lifespans than those from low latitudes. Thispattern may be related to environmental conditions, such as water temperature and seasonal
availability of nutrients. Growth patterns in shells of the northern and southern hard clams(Mercenaria mercenaria and M. campechiensis, respectively) are well-documented throughout
their geographic range. However, most of this work focuses on modern and archaeological
specimens and fossil specimens remain to be investigated. How has the life history of Mercenariachanged during climate conditions colder than today? Here, we provide life history data recorded
in Mercenaria shells from two time intervals (modern and early Pleistocene) at similar latitudes in
the US Mid Atlantic Coastal Plain of North Carolina. The differences in lifespan and growth rates
between these populations will be assessed using the von Bertalanffy growth equation. We
hypothesize that fossil shells from the early Pleistocene Waccamaw Formation (cold climate) will
have longer lifespans and slower growth rates compared with modern specimens (warm climate).
Future work will examine Mercenaria shells across a latitudinal gradient from Florida to Virginia.
Results from this study will contribute to our understanding of how this bivalve species may
respond to rising seawater temperature projected for the end of the 21st century.

Session: Paleoecology and Evolution142

5th International Sclerochronology Conference, ISC 2019

Age determination of the short-finned squid Illex coindetii
using statolith analysis
Mirela Petrić1*, Svjetlana Krstulović Šifner1
1

University of Split, Department of Marine Studies, Ruđera Boškovića 37, P.O. Box 190, 21000 Split, Croatia*presenting author: mpetric@unist.hr

Statolith analysis is widely used method for investigating age and growth of cephalopods,
especially squids. Statoliths are paired calcareous structures mostly composed of aragonite and asmall percentage of organic matter, located in cephalopod equilibrium organs called statocysts.
Statoliths are result of biomineralization, with dark rings deposited during daylight and light rings
during darkness. It is suggested that statolith increments are formed daily, therefore one
increment represents one day. A total of 500 Illex coindetii individuals, with dorsal mantle length
range from 55 to 216 mm, were sampled in the eastern part of the central Adriatic Sea to study
statolith microstructure. Statoliths were surgicaly extracted from the cephalic cartilage and stored
dry in plastic vials. Before grinding, concave side of statoliths were mounted on microscope slideusing thermoplastic resin. Grinding procedure consisted of proper grinding and polishing bothsides of statolith, using lapping film sheets with 30,12, 5 and 0,05 µ grades. The total number ofincrements visible in the statolith microstructure were counted under a light microscope at 200
and 400x magnification, starting from the natal ring in the direction from statolith nucleus to theedge of the dorsal dome. The hatching dates of each squid was back-calculated from date ofcapture and increments counts. The life span of the Adriatic Illex coindetii was estimated at around
six months. The youngest male had a total of 52 days (77 mm DML) and youngest female a totalof 56 days (82 mm DML). The maximum counted age was 186 days (162 mm DML) for males and180 days (188 mm DML) for females. No statistically significant difference in statolith increment
counts was found between the sexes (p = 0.657), with mean values of 108 days (SD = 22.44) and
109 days (SD = 25.66) for males and females, respectively. The oldest individual was caught inspring and youngest during the summer season. Obtained results indicate the existence of
seasonality in squid hatching time in the eastern Adriatic Sea.

Session: Fisheries Ecology and Management1435th International Sclerochronology Conference, ISC 2019

Raman spectroscopy and imaging tools for correlative
analyses in otoliths sclerochronology
Simona Cinta Pinzaru1*, Sanja Matić-Skoko2, Melita Peharda2, Dario Vrdoljak2,
Hana Uvanović2, Calin Firta1,3, Geza Lazar1, Fran Nekvapil1,3, Lucian BarbuTudoran1,3, Maria Suciu1,3, Branko Glamuzina4
1

Babes Bolyai University, Kogalniceanu 1, RO-400084 Cluj-Napoca, Romania
Institute of Oceanography and Fisheries, Šetalište I. Meštrovića 63, 21000 Split, Croatia
3
National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, Ro400293 Cluj-Napoca , Romania
4
University of Dubrovnik, Department for Aquaculture, Ćira Carića 4, 20000 Dubrovnik, Croatia
2*presenting author: simona.cinta@phys.ubbcluj.ro

Although tracking the otoliths development as veritable life history capsule for sclerochronology
studies appeared increasingly attractive in the past decade [1], the complexity and variability inotoliths biomineral formation in various species is far from being understood. Few studies
employed Raman micro-spectroscopy for getting insight into the organic-inorganic fractions andtheir spatial distribution in otoliths for several fish species. Significant reported drawbacks
regarding the otoliths sampling protocol, particularly resins fixation, which can interfere with theoriginal organic matter Raman signal, as well as high variability within individual biomaterial, poor
understanding of biomineralization characteristics for various environmental conditions, or lackof correlative data via scanning electron microscopy and energy dispersive X-ray (EDX)
spectroscopy, place the sclerochronology approach yet in early stage.
Here we present comprehensive Raman micro-spectroscopy and imaging data combined withSEM-EDX line tracking to correlate non-destructively the chemical composition and its highresolution spatial distribution in aragonite otoliths harvested from S. aurata in four regions from
Adriatic Sea. Line scan single point Raman spectra have been recorded using a Renishaw InVia
Reflex Raman system and a DPSS laser emitting at 532 nm for excitation. Spectra were collected
either in short mode, employing just 1 s exposure time, sufficient for inorganic fraction signal, orin extended mode, in the 100-3200 cm-1 range, using 10 s exposure, to complementary assess theorganic fraction Raman characteristics attributed to proteins and amino acids. Different collecting
optics has been employed to assess the influence of the native anisotropy of otoliths on the Raman
signal and imaging data. We show how daily rings are developed with sub-micrometer spatial
resolution and further use the information with controlled scan step of the whole sagittal otolith
sections. Meaningful common structural characteristics assigned for various otoliths groups aswell as variability within individuals are discussed based on the correlated Raman, SEM and EDX
data and prospect their linkage with the existing environmental parameters.
1. Beierlein, L., G. Nehrke, and T. Brey (2015), Confocal Raman microscopy in sclerochronology: A
powerful tool to visualize environmental information in recent and fossil biogenic archives,
Geochem. Geophys. Geosyst., 16, 325– 335, doi:10.1002/2014GC005547.

Session: Biomineralization144

5th International Sclerochronology Conference, ISC 2019

Mediterranean limpets and Mg/Ca ratios - using LIBS toscreen for SST changes and physiological effects
Niklas Hausmann1,2*, Amy Prendergast3, Demetrios Anglos1,41

Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, Greece
BioArCh, University of York, York, UK
3
School of Geography, University of Melbourne, Australia
4
Department of Chemistry, University of Crete, Heraklion, Greece2*presenting author: niklas@palaeo.eu

Elemental analysis of biogeochemical archives is an established technique used to study climate
in a range of applications, including ocean circulation, glacial/interglacial climates, andanthropogenic climate change.
Data from mollusc archives are especially important because of their global abundance and subannual resolution. Despite this potential, they are underrepresented among palaeoclimate
studies, due to enigmatic physiological influences skewing the elemental record. Understanding
the patterns behind these influences will improve data interpretation and lead to thedevelopment of new climate proxies.
Here, we apply extensive mapping of multiple mollusc specimens using the rapid method of Laser
Induced Breakdown Spectroscopy (LIBS) across a wider region to compare and resolve enigmatic
patterns within the elemental record caused by physiological influences.
2D elemental (Mg/Ca) maps of whole limpet shells (Patella caerulea) from across theMediterranean revealed patterns of variability within individual mollusc records as well as within
isochronous parts of specimens. By registering and quantifying these patterns, we establishedpreviously uninterpretable correlations with sea surface temperature (SST): R2>0.8.
We additionally found that the resulting SST equations were specimen specific and would require
additional calibration using other methods (i.e. δ18O). We thus present a combined approach of
fast and cheap LIBS screening and subsequent isotopic analysis of seasonal minima and maxima
only.
This approach thus presents the means to assess annual temperature ranges using oxygen isotope
analysis requiring only 2 samples per shell and season of capture, important for archaeologicalstudies, entirely without oxygen isotope analysis.

Session: Proxy Development: Challenges and Opportunities

145

5th International Sclerochronology Conference, ISC 2019

Pipi shells: a new high-resolution palaeoenvironmentalarchive for south-eastern Australia
Amy Prendergast1*, Vincent Chea1, Michael Godfrey1
1

School of Geography, University of Melbourne, Australia*presenting author: amy.prendergast@unimelb.edu.au

Oxygen isotope ratios from marine mollusc shells have been widely used to reconstruct sea
surface temperature (SST) and seasonal shellfish foraging records from archaeological sites
worldwide. However, the application of this technique to the Australian archaeological record has
so far been limited to a few sites. Pipi shells (Donax deltoides) are common components of manyarchaeological sites in south-eastern Australia. One pioneering study in the 1980s (Godfrey 1988)
employed oxygen isotope analyses of pipi shells to study the Holocene archaeological recordof Discovery Bay in Victoria. However, this study was constrained by the technology andtechniques of the time. Recent advances in mollusc shell growth increment analysis(sclerochronology) and high-resolution geochemical sampling as well as improvements in mass
spectrometry technology have enabled the reconstruction of sub-monthly sea surface
temperature records from intertidal mollusc shells, thus enabling more robust and reliable
reconstructions. In light of these recent advances, we reassess the utility of Donax deltoids shells
as archives for SST and seasonality information in south-eastern Australia.
To validate whether this species is a faithful year-round palaeoenvironmental recorder, wecollected live D. deltoids from Discovery Bay, Victoria each month for a year. We analysed theintra-annual variability of δ18O in modern live-collected shells and sea water and compared δ18Oderived SST reconstructions with instrumental SST records. Shell-derived SSTs were highly
correlated with instrumental SST records over the period of collection. This suggests that theseshells are reliable palaeothermometers. This study demonstrates the utility of applying advanced
sclerochronological techniques to Australian shell middens and shows that pipi shells hold great
potential for reconstructing monthly-resolved SST records and seasonal foraging practices insouth-eastern Australia.

Session: Sclerochronology and Human-Environmental Interactions: Past and Present

1465th International Sclerochronology Conference, ISC 2019

Exploring the potential of Arctic coralline algae as apaleosalinity proxy
Lina M. Rasmusson1*, Jochen Halfar2, Jason M. Hall-Spencer3, Hans W.
Linderholm1
1Regional Climate Group, Department of Earth Sciences, University of Gothenburg, SE-40530 Gothenburg,
Sweden2
Department of Chemical and Physical Sciences, University of Toronto at Mississauga, L5L 1C6 Mississauga,
Canada3
Marine Biology and Ecology Research Centre, School of Marine Science and Engineering, Plymouth University,
PL48AA Plymouth, UK*presenting author: lina.rasmusson@gu.se

As Arctic glaciers and ice sheets are melting rapidly, ocean salinity is declining. Salinity determineswater density and strongly influences the strength and direction of currents and ocean circulation.
It thus has great impacts on regional and global climate as it drives the transport of heat andenergy. Establishing if salinity shifts are occurring naturally or if we are facing extreme events canhelp us predict the future impact of lowered salinity on climate patterns and ecosystems. As
existing salinity reconstructions of Arctic waters are few, short and of low temporal resolution,
new reliable salinity proxies are needed. For instance, the Intergovernmental Panel on Climate
Change (IPCC) reported on the lack of such proxies in their report on the impacts of climate changeon the oceans. A promising way to go for this purpose is Rhodochronology, the methodology
examining how calcifying red algae, also referred to as coralline algae, are capturing
environmental fluctuations within their annually banded structures. By analysing the traceelement- and isotopic composition in the growth layers of these algae, it might be possible to trace
salinity variability hundreds of years back in time. Clathromorphum compactum, the species ofinterest in this project, has a geographic distribution throughout the high Arctic, where most otherorganisms suitable for sclerochronological surveys are absent. Algae have and will be collectedaround the coastlines of Svalbard and Greenland; samples will be collected along a natural salinity
gradient in a fjord system in Greenland summer 2019. The trace elements Ca, Mg, Ba, Mn, Li, Na
and Sr will be determined using Laser Ablation Inductively Coupled Plasma Mass Spectrometry(LA-ICPMS) and the levels of δ18O using mass spectrometry with the aim to investigate how thesignal changes in accordance to salinity. All these elements have given slight indications, but not
yet proven, salinity related responses in other organisms. Moreover, C. compactumwill be kept ina laboratory set-up consisting of aquaria with different salinities in order to detect theincorporation of the elements and δ18O in controlled salinity settings. This project focuses on
calibrating and evaluating the use of this method for making salinity reconstructions, hence
validating the huge potential calcareous algae have as a historical salinity archive. The
reconstructions will provide highly needed data and serve as a framework for future climate
modelling, useful for researchers and policymakers when assessing salinity related effects ofclimate change in the marine environment.

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Coral calcification and sclerochronology during the Middle
Miocene Climate Transition
Markus Reuter1*, Philipp Spreter1, Regina Mertz-Kraus2, Thomas C. Brachert1
1Institute of Geophysics and Geology, University of Leipzig, Talstraße 35, 04103 Leipzig, Germany
Institute for Geosciences, Johannes Gutenberg-University Mainz, Johann-Joachim-Becher-Weg 21, 55128
Mainz, Germany
2*presenting author: markus.reuter@uni-leipzig.de

The rise of atmospheric pCO2 due to anthropogenic burning of fossil fuels is unprecedented in thelast 300 million years (Ma). In addition to ocean warming, rising pCO2 causes ocean acidification,
which endangers calcification in many marine calcareous biota such as reef corals. Nevertheless,coral reefs were more widespread-than-present during periods with high pCO2 in the geologicalpast, because pCO2 changes were likely slow allowing the oceanic carbonate system to maintainhigh saturation with calcium carbonate. For testing model predictions on the long-term carbonate
buffering capacity of the oceans coral calcification data from such periods are mandatory, but
detailed coral calcification records from deep geological time are still lacking because the porous
aragonitic skeletons of scleractinian corals, as a general rule, quickly undergo biological anddiagenetic degradation. Here we present high resolution (0.1 mm sampling distance) stable
isotope (δ18O, δ13C) and calcification (skeletal density and extension) data from two fossil
Poritescorals of late Langhian – early Serravllian age (ca 14 – 13 Ma) that were discovered at
Pötzleinsdorf and Drasenhofen in the Vienna Basin (Austria). According to careful screening
procedures (SEM, XRD, X-radiography), the corals under study are in a rather pristine state ofpreservation retaining their original skeletal aragonite, pore space and microstructural details.
This exceptional state of preservation makes them the oldest scleractinian corals known so far
suited for combined stable isotope sclerochronology and radiodensitometry. The corals
investigated represent the Middle Miocene Climate Transition (MMCT), a phase of major global
cooling at ca 15 – 13 Ma following the Middle Miocene Climatic Optimum (MMCO), which was thewarmest episode of the Neogene. Climate models assume atmospheric CO2 concentrations of 400
ppmv during the MMCO, which decreased to 200 ppmv at the end of the MMCT. The
sclerochronological records presented by us offer a rare opportunity to study the responses ofreef coral calcification during this time of global pCO2 and climatic turnover.

Session: Climate and Oceans: Past, Present and Future148

5th International Sclerochronology Conference, ISC 2019

Do scales and otoliths tell the same shad story?
Elodie Réveillac1*, Jean-Luc Baglinière2, Elise Sola3, Emilien Lasne2, Anthony
Acou4, Christophe Pécheyran3, Eric Feunteun5
1

Agrocampus Ouest, UMR 0985 ESE Agrocampus Ouest-INRA, 65 rue de St Brieuc 35000 Rennes, France
INRA, UMR 0985 ESE Agrocampus Ouest-INRA, 65 rue de St Brieuc 35000 Rennes, France
3
MNHN, UMR BOREA 7208 MNHN-CNRS-Sorbonne Université-IRD 207-UCN-UA, CRESCO Station marine de
Dinard, 38 rue du Port Blanc, 35800 Dinard, France
4
AFB, UMS Patrinat AFB-MNHN-CNRS, CP41, 36 rue Geoffroy Saint-14 Hilaire, 75005 Paris, France
5
IPREM/LCABIE UPPA-CNRS, 2 avenue Angot, Hélioparc Pau Pyrénées, 64053 Pau cedex 9, France
2*presenting author: elodie.reveillac@agrocampus-ouest.fr

Do fish scales and otoliths tell the same story regarding the events marking out the life history?
Anadromous Twaite (Alosa fallax) and Allis (Alosa alosa) shads are good examples to answer thisquestion. These species undergo successive migrations at different periods of their life cycle intovery contrasted environments. Spawning and juvenile growth occur in freshwater and juveniles
stay some months at sea before migrating sea back to freshwater. Allis shad is generally
considered as a semelparous species while Twaite shad is a multi-spawner species. Then, during
their life cycle, physiological, morphological and environmental changes are recorded in hard
structures as scales and otoliths.
In anadromous fish, life history traits are often described using scales reading. This non-lethal
method is commonly used to estimate traits such as the growth, total age and age at reproduction
and number of spawning events. Particularly during pre- and spawning events there is aremobilization of calcium carbonate stored in scales because they ensure a source of minerals
used during sexual maturation. This results in a resorption process in the scale, in an erosion
phenomenon of the edge and the formation of a spawning mark if the fish survives.
In shads, otoliths are less commonly used to estimate life traits history than scales. Otolith inert
structure is considered unaltered by internal physiological nor biochemical processes once formed(crystallized). Otolith structure is only modulated by ongoing processes (decreasing or increasing
growth, metamorphosis etc...). Likewise, the chemical composition of otoliths is modified along
all the life cycle by migrations in environments of different chemical composition like the sea andfreshwater where both shad species spawn.
Taking into account these findings, shad spawning events are assumed to be printed in scales
structure and in otoliths chemical composition. Allis shad is hypothesized to exhibit only one
ultimate spawning record whereas the Twaite shad may show several ones.
Our study analyzes the match or mis-match between scale structure and otolith chemicalcomposition in recording spawning events in Allis and Twaite shads. Results should provide
guidelines for using hard structures as proxy of fish life history events.

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An integrated carbon and oxygen isotope approach toreconstructing past environmental variability in thenortheast Atlantic Ocean
David Reynolds1*, Ian Hall2, Sophie Slater2
1

Laboratory of Tree Ring Research, University of Arizona, Bryant Bannister Tree Ring Building, 1215 E Lowell St,
Tucson, AZ, 85721, USA
2
School of Earth and Ocean Science, Cardiff University, Main Building, Park Place, Cardiff, CG10 3AT, UK*presenting author: davidreynolds@email.arizona.edu

The combined influence of temperature and the isotopic composition of the seawater [d18Ow]
often precludes the use of oxygen isotope (d18O) records, derived from marine carbonates, toreconstruct absolute seawater temperatures, without the application of an independent d18Ow
proxy. Here we investigate the application of carbon isotope records (d13Cshell), derived from thelong-lived marine bivalve Glycymeris glycymeris, as a proxy for d18Ow variability. Our analyses
indicate G. glycymeris d13Cshelldata derived from growth increments >20 years of age containstrong ontogenetic trends (-0.013‰ yr-1, R2=0.97). These analyses demonstrate that, coupled withthe ontogenetic trends, 54% of the variability in G. glycymeris d13Cshell records can be explained by
a combination of the marine Suess effect, physical (salinity and riverine input) and biologicalprocesses (primary production). The application of these d13Cshell data in conjunction with coregistered d18Oshell and growth increment width series, each of which have been shown to besensitive to seawater temperature and primary productivity respectively, can therefore provide
new insights into past environmental variability and help constrain uncertainties inreconstructions of past seawater temperature variability.

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5th International Sclerochronology Conference, ISC 2019

Stylasterids: a new paleoceanographic archive?
Ana Samperiz1,2*, Laura Robinson2, Melanie Leng3, Nadia Santodomingo4, Brad
Rosenheim5, Katharine Hendry2, Veerle Huvenne6
1School of Earth and Ocean Sciences School, Cardiff University,Cardiff, UK
School of Earth Sciences, University of Bristol, Bristol, UK
3
NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, UK
4Natural History Museum, London, UK
5
College of Marine Science, University of South Florida, Florida,USA
6
National Oceanography Centre, Southampton, UK
2*presenting author: samperizvizcainoa@cardiff.ac.uk

Stylasterids are a commonly found deep-sea coral taxon that build their skeletons from either
calcite or aragonite (or both). Their potential as paleoceanographic archives remains unexplored
and robust geochemical proxy data collected from modern specimens is very limited. Ninety-threestylasterids were selected from locations including the Southern Ocean, Equatorial Atlantic, North
Atlantic and Galápagos Islands spanning a range of depths from 63 to 2894 m and temperaturesfrom 0 to 17°C. Samples were identified up to species level when possible. They included 20
species belonging to 7 genera. These were Adelopora sp., Cheiloporidion sp., Conopora sp., Errinasp., Errinopsis sp., Inferiolabiata sp. and Stylaster sp. Fifty-six specimens were analysed for skeletal
mineralogy. Sixteen samples were calcitic, and 40 were aragonitic. Oxygen and carbon (δ18O andδ13C) isotopic composition was measured in all the specimens. Five specimens were sub-sampled
in the main trunk, secondary branches and growing tips. All data were below equilibrium, with thetips of the colonies having the lightest values, and the trunk being the heaviest. The δ18O and δ13C
range within a single specimen is lower compared to published values in deep-sea scleractiniancorals. All the specimens were subsampled in the main trunk. Their δ18O and δ13C was measured
and compared to local hydrographic data to gain insight into calcification mechanisms and test
their use as paleotemperature archives. Different isotopic values were found between aragonitic
and calcitic samples. Calcitic corals showed less depleted values from equilibrium for δ18O but ahigher depletion for δ13C. The data indicate that environmental temperature is recorded in theskeletal chemistry of stylasterid corals. A global δ18O:temperature calibration for aragonitic
stylasterids was produced. This calibration showed a mean depletion of 0.97‰ from equilibrium.
This work highlights the potential application of stylasterid coral δ18O data to reconstruct ancientseawater temperature.

Session: Proxy Development: Challenges and Opportunities151

5th International Sclerochronology Conference, ISC 2019

High resolution analysis of bivalve shell by NanoSIMS
Yuji Sano1*, Kotaro Shirai1, Naoto Takahata1, Akizumi Ishida2
12

Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
Institute for Excellence in Higher Education, Tohoku University, Aobaku, Sendai 980-8576, Japan*presenting author: ysano@aori.u-tokyo.ac.jp

We developed a method to measure Mg/Ca, Sr/Ca and Ba/Ca ratios of natural carbonates withsupper-fine structure using high lateral resolution secondary ion mass spectrometer, NanoSIMS[1]. This method was successfully applied into geochemical analysis of foraminifera test [2] andcoral skeleton [3]. Previous high resolution analysis of cultivated giant clam shell with 2 micrometer spot [4] showed a diurnal variation in the Sr/Ca ratio, which may reflect the daily light cycle.
Based on the calibration between the insolation and Sr/Ca ratios, we reconstructed solar radiationof Middle Holocene using a fossil giant clam shell [5]. In order to apply state-of-the-art analyticalmethod to other bivalve shell, we measured Mg/Ca, Sr/Ca and Ba/Ca ratios of a Mediterraneanmussel (Mytilus galloprovincialis) collected at the Otsuchi bay, on the Pacific coast of northeasternJapan. This bivalve was living at intertidal zone and colletected on September 6th 2011, that may
have suffered by a great tsunami induced by the 2011 magnitude 9.0 Tohoku earthquake on March
11th. Soft tissues were removed from mussel and the shell was cut along the maximum growthaxis and mounted in Araldite disk together with a carbonate standard. This species is known toform a growth line with organic matter daily or bidaily at the air exposure time, which may
facilitate age-model with tidal record by counting the etched-stained lines. After polishing andgold coated, we analyzed trace elements of the shell by low resolution (10-micro-meter spot at
100-micro-meter interval) and high resolution (2-micro-meter spot at 3-micro-meter interval)
using NanoSIMS installed at The University of Tokyo. Annual variations of Mg/Ca ratios, high in
winter and low in summer, are clearly visible at low resolution, smilar to those of caltivated giant
clam shell [4]. Mg/Ca ratios of the inner edge, corresponding to most recent date (September2011) together with data of December 2010 estimated by the age-model, show daily or bidaily
cyclic changes at high resolution. High Mg/Ca ratios are probably derived from the time of air
exposure at low tide when the Ca transportation is blocked. Ref: [1] Sano et al. Anal. Sci. 21, 1091,
2005. [2] Kunioka et al. G-Cubed 7, Q12P20, 2006. [3] Shirai et al. Geochim. Cosmochim. Acta 72,
5386, 2008. [4] Sano et al. Nature Commu. 3, 761, 2012. [5] Hori et al. Scientific Reports, 5, 8734,
2015.

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8.2 ka event North Sea hydrography determined by bivalve
shell stable isotope geochemistry
Juan Estrella-Martínez1, Philippa Ascough2, Bernd Schöne3, Paul Butler4, James
Scourse4*
1

School of Ocean Sciences, Bangor University, Askew St., Menai Bridge LL59 5AB, UK
NERC Radiocarbon Facility, Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish
Enterprise Technology Park, East Kilbride, G75 0QF, UK
3
Institute of Geosciences, Johannes Guttenberg University, J.-J.-Becher-Weg 21, D-55128, Mainz, Germany
4
Centre for Geography and Environmental Sciences, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK
2*presenting author: j.scourse@exeter.ac.uk

The abrupt 8.2 ka cold event has been widely described from Greenland and North Atlantic records
as a response to a perturbation in the Atlantic Meridional Overturning Circulation arising from
freshwater outburst from the terminal Laurentide Ice Sheet. The expression of this event is poorly
documented from the Atlantic shelf seas. We present an annually-resolved temperature andwater column stratification reconstruction based on stable isotope geochemistry of Arctica
islandica shells from the Fladen Ground (northern North Sea) temporally coherent with Greenland
ice core records. Our age model is based on a growth increment chronology obtained from fourradiometrically-dated shells covering the 8286-8105 cal BP interval. Our results suggest that asudden sea level rise event (SSLR) recognised in southwest Scotland forced water column
stratification between 8320 and 8220 cal BP. Thirty years later, cold conditions associated withthe 8.2 ka event inhibited water column stratification but an eventual incursion of sub-Arctic
waters into the North Sea re-established density-driven stratification. The water temperatures
reached their minimum of ~3.8 °C 55 years after the SSLR. Intermittently-mixed conditions werelater established when the sub-Arctic waters receded.

Session: Climate and Oceans: Past, Present and Future153

5th International Sclerochronology Conference, ISC 2019

Mussel periostracum as a high-resolution archive of soft
tissue δ15N records in coastal ecosystems
Kotaro Shirai1*, Kentaro Tanaka1, Quang Dung Le2, Naoko Murakami-Sugihara1,
Kaoruko Mizukawa3, Liqiang Zhao1
1

Atmosphere and Ocean Research Institute, The University of Tokyo, Japan
Institute of Oceanography and Environment, Universiti Malaysia, Terengganu, Malaysia
3
Department of Environmental Science on Biosphere, Tokyo University of Agriculture and Technology, Japan
2*presenting author: kshirai@aori.u-tokyo.ac.jp

To understand sources of the anthropogenic nitrogen inputs along coast, the development a newand more efficient tool for monitoring is needed. Given filter feeding bivalves are considered as
ideal bioindicator for environmental pollution, including nitrogen enrichment, since the isotopic
composition in their soft tissues often reflects isotopic composition of POMs in water bodies.
Recently we have also demonstrated that the carbon isotopic ratio of mussel periostracum canalso be used as a proxy for time series fluctuation of POM isotopic composition. Hence, it is anattempt to test the periostracum of mussel as proxy for nitrogen monitoring in along the coastal
waters based on stable isotopic approach.
Mussel samples were quarterly or seasonally collected from coastal areas of Japan in 2015/2016.
Seaweed samples (Ulva sp.) were also collected when available. Nitrogen isotopic compositions
were analyzed by standard methods using IRMS. Nitrogen isotopic composition of muscle andperiostracum showed strong correlation, indicating that the composition of periostracum reflects
soft tissue composition. Nitrogen isotope ratios of muscle and seaweed showed positive, but
weak, correlation. This indicates that the isotopic composition of mussel tissue is affected byisotopic composition of nitrate available for seaweed, through compositional changes in POM
containing phytoplankton that also assimilate the nitrate. These results suggested that the mussel
periostracum is a useful proxy for elucidating the coastal nitrogen geochemical cycle.

Session: Proxy Development: Challenges and Opportunities

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5th International Sclerochronology Conference, ISC 2019

Sclerochronology and 14C dating applied on bivalve
Glycymeris pilosa from the Adriatic Sea
Andreja Sironić1*, Krešimir Markulin2, Slaven Jozić2, Hana Uvanović2, Damir
Borković1, Carin Andersson3, Melita Peharda2
1Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia
Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, 21 000 Split, Croatia
3
NORCE Norwegian Research Centre, Bjerknes Centre for Climate Research, Jahnebakken 5, 5007 Bergen,
Norway2*presenting author: asironic@irb.hr

This study combines radiocarbon analysis and sclerochronology research, an approach that to thebest of our knowledge, has not yet been applied using bivalves from the Mediterranean Sea. We
analysed shells from the North Adriatic Sea: live- and dead-collected specimens of the infaunal
bivalve Glycymeris pilosa (Linnaeus, 1767) and two dead-collected specimens of Glycymeris sp.
According to crossdating results, growth increment time series obtained from acetate peels of thedead-collected G. pilosa (S3FP11) indicate the potential for creating longer chronologies from live
and dead-collected specimens. Based on the radiocarbon results obtained from a growthincrement assigned to AD 1950 in a live-collected shell, the reservoir age (R) and reservoir
correction (ΔR) are 264 ± 23 years and -6 ± 32 years, respectively. One of the three sub-fossil shells
reflected 14C bomb peak and could be assigned to a time period from AD 1965 to AD 2013. The
other two sub-fossil specimens were dated with reservoir age correction calculated as mean fromAD 1950 increment growth and ΔR reported by Siani et al. (2000; Radiocarbon 42:271-80) and, byuse of Bayesian analysis, were placed in periods from 15th to 17th century (S3F5) and from 17th to19th century (S3F3). The greatest longevity was seen in the dead-collected Glycymeris sp. specimen
S3F3, estimated to be ~130 years (started growing AD 1678-1742 and died AD 1826-1860),
indicating the potential to extend Glycymeris growth increment chronologies to past centuries.
The highest ∆14C values obtained correspond to the calendar year 1974. The 14C record obtained
from G. pilosa correlates well with the modelled surface ocean (mixed-layer) bomb pulse curve(Reimer et al. 2009; Radiocarbon 51:1111-50) and with model developed for Mediterranean Sea
by Ayache et al. (2017; Biogeosciences 14: 1197-213). Research has been conducted in aframework of the project SCOOL (IP-2014-09-5747) supported by the Croatian Science
Foundation.

Session: Climate and Oceans: Past, Present and Future155

5th International Sclerochronology Conference, ISC 2019

Constraining palaeo-CO2 reconstructions though B isotopes
in marine carbonates using the NU Plasma II MC-ICP-MS
Sophie Slater1*, Caroline Lear1
1

School of Earth and Ocean Sciences, Cardiff University, UK*presenting author: SlaterS3@cardiff.ac.uk

Carbonate organisms are a useful archive for a variety of palaeoclimatic proxies, including theboron isotope (δ11B) proxy for seawater pH. Boron is fractionated into different species in its
aqueous state: boric acid and borate ions; the ratio of boric acid to borate in seawater is strongly
pH-dependent. Isotopic fraction between the species therefore means that the δ11B of either
dissolved species is a function of both pH and the δ11B of the total B dissolved in seawater. Because
foraminiferal B content is derived from the borate species only, foraminiferal δ11B is a powerfularchive to reconstruct past variations in pH and hence CO2. However, on geological (several
millions of years) timescales, uncertainties in the estimates of the δ11B of the total B dissolved inseawater limit reconstructions of absolute pH, and hence pCO2 from foraminiferal δ11B. It is hopedthat this uncertainty may be reduced by using other carbonate materials as a boron archive. For
example, it has been suggested that biomineralization of some molluscs, brachiopods, and otoliths
may occur within a self-regulated fluid with respect to pH. Such biogenic carbonates may be lesssensitive to ambient seawater pH, and hence may have potential as recorders of long-termchanges in the δ11B of total B dissolved in seawater.
To date, the vast majority of δ11B records derived from small biogenic carbonate samples (e.g.
foraminifera) have been generated using either thermal ionisation mass spectrometry (TIMS) or
Thermo Neptune multi-collector inductively-coupled plasma mass spectrometers (MC-ICP-MS).
Cardiff University’s CELTIC Laboratory recently installed a NU Plasma II MC-ICP-MS. Our initial aim
was therefore to determine whether this instrument can achieve the required precision andaccuracy to enable investigations of a range of biogenic carbonate using the δ11B proxy. We tested
its precision and accuracy using 3 concentrations (100ppb, 50ppb and 10ppb) of the standard SRM
NIST951a (boric acid). We used standard-sample bracketing to offset drift during the course of arun. At the target concentration of 50ppb, the ±1SD precision for the standard was 0.10‰ whentreated as a sample in triplicate. This is similar to that reported for the Thermo Neptune MC-ICPMS, and indicates that the NU Plasma II MC-ICP-MS will be capable of exploiting the δ11B proxy ina range of biogenic carbonates, including molluscs, brachiopods and foraminifera. We also discuss
our immediate sampling strategy, which includes a combination of culture study, modern, andfossil material.

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Variation of carbon isotopic composition in otoliths ofNortheast Arctic cod (Gadus morhua)
Szymon Smoliński1*, Côme Denechaud1,2, Gotje von Leesen3, Jane A Godiksen1,
Audrey J. Geffen1,2, Peter Grønkjær4
1

Institute of Marine Research, Bergen, Norway
Department of Biology, University of Bergen, Norway
3
Faculty of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland
4
Aquatic Biology, Department of Bioscience, Aarhus University, Denmark2*presenting author: szymon.smolinski@hi.no

The isotopic composition of carbon in otoliths of fish may be a useful tracer of metabolic rates andhelp to reconstruct the marine food web structure in the past. However, proper interpretation of
isotopic fluctuations requires understanding of their physiological and environmental drivers. The
aims of this work will be to evaluate different sources of variations in the carbon isotopic signalsof Northeast Arctic cod (Gadus morhua) otoliths, including environmental (e.g. temperature) or
physiological controls (e.g. changes of growth rate of individual fish), and to investigate their longterm temporal variability. Multidecadal archival collection of otoliths from fish sampled in the
Lofoten area (Norway), which constitutes the main spawning site of this stock, will be used in the
study. For δ13C analysis of otolith aragonite, individual annual growth increments from immatureand mature stages will be micromilled and measured by isotope-ratio mass spectrometry.
Simultaneously, all annual ring increments of the otoliths will be measured as a proxy of fishsomatic growth. Series of mixed-models will be developed in order to analyse different intrinsic
and extrinsic sources of variation in carbon isotopes and fish growth. This statistical technique canalso help to explore relationships between composition of carbon isotopes and growth changes
during a lifetime of an individual fish estimated with biochronology. Synchronous fluctuations in
the isotopic composition over time will be further explored considering information on theisotopic composition of potential prey in the feeding area (the Barents Sea), data on dissolved
inorganic carbon and other physical properties of water masses. Otolith carbon isotopic analysis
has the potential to provide a direct link revealing how environmental conditions are affecting cod
metabolic activity. Identification of these responses to the changing environment can support
sustainable management of the Northeast Arctic cod, which constitutes the largest cod stock in
the world.

Session: Growth, Bioenergetics and Ecosystems

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5th International Sclerochronology Conference, ISC 2019

Otolith shape variations between artificially stocked andautochthonous pikeperch (Sander lucioperca)
Allan T. Souza1*, Katerina Soukalová1, Vilém Děd1, Jan Kubečka1
1

Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, Na Sádkách 7, 370 05 České
Budějovice, Czech Republic*presenting author: allan.souza@hbu.cas.cz

Fish stocking (i.e. introduction of allochthonous individuals into the ecosystem) is one of the mostwidespread and frequent management strategy adopted by stakeholders in freshwater systems,
which usually spend relatively large part of their budget in this activity. However, the contributionof stocked fish to the population is seldom investigated, and hence the effectiveness of thisstrategy is virtually unknown for many populations. Understanding the contribution of stockedfish into the population is crucial because it allows the estimation of survival and growth rates andthe contribution of stocked fishes to the population. The differentiation between stock and nonstocked fish can be done using different techniques, which include fin clipping, otolith staining andmicro wire tags, but the results are not always satisfactory, often leading to a decreased survival
rate of marked fish, biasing the stock assessment. Otoliths are conservative structures in which
their shape often vary according to several ecological and environmental factors, thus serving as
an excellent tool for ecologists and fishery scientists. To evaluate the shape differences on sagittal
otoliths of stocked and autochthonous fish, 40 sagittal otoliths of stocked pikeperch (Sander
lucioperca) and 40 sagittal otoliths originating from a rearing facility were compared using 4 shapeindexes (circularity, ellipticity, roundness, rectangularity). Results indicated slight differencesamong stocked and non-stocked fish suggesting that this technique can be used to discriminate
the natal origin of fish in a much faster and cheaper way than commonly used techniques.

Session: Fisheries Ecology and Management158

5th International Sclerochronology Conference, ISC 2019

EDX in Bouligand pattern sclerochronology
Maria Suciu1,2*, Lucian Barbu-Tudoran1,2, Fran Nekvapil1,2, Simona Cinta
Pinzaru2, Branko Glamuzina3
1

National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, Ro400293 Cluj-Napoca, Romania
2
Babes-Bolyai University, Kogalniceanu 1, RO-400084 Cluj-Napoca, Romania
3
University of Dubrovnik, Department for Aquaculture, Ćira Carića 4, 20000, Dubrovnik, Croatia*presenting author: maria.suciu5@gmail.com

Elemental composition of natural biomaterials is determined by the genetic inheritance ofindividuals and by the physical-chemical characteristics of the inhabiting environment and/or its
stressful changes. To track such changes, we describe here advances in Energy-dispersive X-ray
spectroscopy (EDX) analysis of crustacean skeletons which are crucial for correct correlation of thechemical composition, morphology and biological functions. The crustacean wildlife is famously
renown and admired for the species colours and their shell structure and arrangement. Line scan
EDX combines scanning electron microscopy imaging with cross-section elemental spectroscopy
technique. Through these combined methods we analyzed the elemental minute differences in
the growth of the exoskeletons and infer from that, meaningful seasonal environmental influenceson the crustacean development. Comparative EDX datacollected from C. sapidus, one invasive [1]crab species in Mediterranean area, as well as from C. aestuarii green crab cuticles revealed thatthe generally known “universal” Bouligand pattern in crustacean skeletons showed completely
distinct elemental composition. C. sapidus revealed the lowest Ca level in epicuticle, further
increasing in exocuticle and showing an unusually high amount (up to 71.6 wt%) in endocuticle.
Lowest C, O and Mg level in endocuticle and highest P content in exocuticle completely
differentiate the elemental pattern in blue compared to green crab cuticle. Such feature, could
suggest distinct protective role of endocuticle as the first mineralized load-bearing layer after crab
molting. In line scan of elemental composition, EDX data constantly showed higher content of C
associated to corresponding lower content of Ca, Mg and P, particularly in epicuticle, which mostly
contains amorphous minerals and waxy lipoproteins. The present data infirm the previous report[2] on the presence of Br or Sr in blue shell and their influence in C. sapidus coloration as well as
their incorporation in cuticle from heavy metals polluted water of their Adriatic environment.
1. Onofri V, Dulčić J, Conides A, Matić-Skoko S, Glamuzina B (2008). The occurrence of the blue
crab, Callinectes sapidus Rathbun, 1896 (Decapoda, Brachyura, Portunidae) in the Eastern Adriatic(Croatian Coast). Crustaceana, 81, 403-409.
2. Katsikini M (2016) Detailed spectroscopic study of the role of Br and Sr in coloured parts of the
Callinectes sapidus crab claw. Journal of Structural Biology, 195, 1-10.

Session: Biomineralization

159

5th International Sclerochronology Conference, ISC 2019

Assessing seasonality and life history of Baltic Sea Astarte
borealis (Bivalvia) using oxygen isotope ratios measured byhigh-precision SIMS
Donna Surge1*, David K. Moss2, Ian J. Orland3, Michael L. Zettler4
1

University of North Carolina-Chapel Hill, Department of Geological Sciences, Chapel Hill, NC, USA
Sam Houston State University, Department of Geography & Geology, Huntsville, TX, USA
3
University of Wisconsin-Madison, Department of Geoscience, Madison, WI, USA
4
Leibniz-Institute for Baltic Sea Research, Rostock, Germany
2*presenting author: donna64@unc.edu

The bivalve Astarte borealis (Schumacher, 1817) is an important component of the biomass inarctic-boreal seas and oceans and has a relatively long lifespan, living for several decades.
Therefore, it is potentially a useful recorder of environmental information. Our recent
sclerochronologic studies of this relatively small bivalve species in the Baltic Sea have found some
populations exhibiting easily identifiable annual growth increments, while annual increments inother populations are less clear. This morphological difference in shell growth records is likely
related to local environmental conditions. Because of their small size and narrow or complex
growth increments, micromilling of A. borealis shells from the Baltic Sea was not possible. Here,
we present a high-resolution submonthly resolved record of oxygen isotope variability from one
Baltic Sea A. borealis shell using secondary ion mass spectrometry (SIMS; WiscSIMS lab at UWMadison). We report oxygen isotope ratios from 307 spots (10 mm diameter) in a transect that
follows growth direction. Along this transect, variation of oxygen isotope ratios is quasi-sinusoidal
and reflects an estimated 17+ years of growth (shell height = 12.5 mm). The average range of ofoxygen isotope ratios is 2.4‰ (VPDB; max = −3.24±0.43‰, n = 18; min = −5.62±0.29‰, n = 17),
suggesting a seasonal temperature variation of ~11°C. This seasonal range is similar to the average
range of bottom water temperature measured at a nearby site (~10°C). Note, however, that theoxygen isotope ratio of water cannot be well constrained or assumed to be constant to precisely
calculate temperature using the oxygen isotope ratio of shell carbonate. Our interpretation of ofoxygen isotope time series shows that annual growth checks occur during winter. Comparison
with water monitoring data will allow us to better understand the life history andenvironmental/ecological records contained in this new bio-archive.

Session: Growth, Bioenergetics and Ecosystems

160

5th International Sclerochronology Conference, ISC 2019

Microscale magnesium distribution in shell of Mytilus
galloprovincialis: An example of multiple factors controlling
Mg/Ca in biogenic calcite
Kentaro Tanaka1*, Nobuyuki Okaniwa2, Tsuzumi Miyaji3, Naoko MurakamiSugihara1, Liqiang Zhao1, Kazushige Tanabe4, Bernd R. Schöne5, Kotaro Shirai1
1

Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba,277-0882, Japan
2
Rural Environment Division, Rural Policy Department, Rural Development Bureau, Ministry of Agriculture,
Forestry and Fisheries, 1-2-1 Kasumigaseki, Chiyoda-ku, Tokyo, 100-8950, Japan
3
National Ainu Museum, 2-3-4 Wakakusa-cho Shiraoi-cho, Hokkaido, 059-0902, Japan
4
University Museum, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
5
Institute of Geosciences, University of Mainz, Johann-Joachim-Becher-Weg 21 55128 Mainz, Germany*presenting author: kentaro.tanaka@aori.u-tokyo.ac.jp

Since magnesium concentration in biogenic calcite is considered to reflect water temperatureduring precipitation, the magnesium-to-calcium ratio (Mg/Ca) has been examined as a proxy forwater temperature in paleoclimate research, although factors other than temperature may also
influence Mg/Ca in biogenic calcite, thereby introducing a potential bias in the relationshipbetween Mg/Ca and temperature observed in inorganic systems. To better understand factors
controlling Mg incorporation into the calcitic shells of bivalves, the distribution of Mg in the
Mediterranean mussel Mytilus galloprovincialis was studied, being compared with ambient sea
surface temperature (SST), shell growth rate and the distribution of organic matter. Although apositive relationship between Mg/Ca and SST was observed, Mg/Ca had been influenced byadditional factors such as organic-bound Mg. In fact, organic-rich growth lines contained more Mg
than the adjacent growth increments. Furthermore, Mg/Ca was relatively enriched in theundulated shell portions, i.e. those with higher curvature. Variations of shell Mg/Ca ratios could
neither be solely explained by SST, growth rate or organic matter. We hypothesize that zoning of
Mg2+/Ca2+ within the extrapallial fluid at the time of formation of the undulated shell portion may
have occurred, and the heterogeneous Mg distribution in contemporaneously formed shell
portions thus limits the usability of Mg/Ca in shells of Mytilus sp. as a proxy for water temperature.

Session: Proxy Development: Challenges and Opportunities

161

5th International Sclerochronology Conference, ISC 2019

Highly synchronous shell growth records in Laternula
elliptica from Adelie Land (East Antarctica)
Julien Thébault1*, Hana Uvanović2, Laurent Chauvaud1, Erwan Amice1, Melita
Peharda2
1
2

Université de Brest – CNRS, 29280 Plouzané, FranceInstitute of Oceanography and Fisheries, 21000 Split, Croatia*presenting author: julien.thebault@univ-brest.fr

The scientific community recognizes that global change is affecting all the Earth’s ecosystems.
Polar settings are among those that will be most impacted because they are very sensitive to small
increases in the annual mean temperature. Whereas there are strong lines of evidence that the
Arctic is warming much faster than any other biome worldwide, the situation is more complex for
the Antarctic. The Peninsula and Western Antarctica are warming at a rate about 10 times fasterthan the global average but other parts of the White Continent did not experience large
temperature changes over the past 50 years. Predicting the future of Antarctica and its sensitive
ecosystems in a warming world is still tricky because of the lack of robust environmental data andbecause scientists do not really well understand the mechanisms underlying snowfall, ice sheet
stability, and sea-ice dynamics in these remote areas.
Changes in the phenology of physical and ecological variables associated with climate change arelikely to have signiﬁcant effects on many aspects of the polar benthic ecosystems. Here, we
focused on a circum-antarctic bivalve species, Laternula elliptica, living up to four decades. The
main goal was to assess the potential of these shells as archives of zoobenthic response toenvironmental variability. Most of informations previouly published on this species were based on
specimens from the Antarctic Peninsula and nearby islands, where impacts of climate change are
already significant. Conversely, we worked on a population from East Antarctica in order to get abaseline of normal conditions before the effects of global warming become too strong. In January
2016, 29 live specimens were collected at a depth of 21 m close to the French station Dumontd’Urville (Adelie Land). Shells were processed using standard sclerochronological procedures toinvestigate inter-annual shell growth dynamics. Once detrended, individual shell growthtrajectories (standardized growth indices) were highly synchronous, with an alternance ofnegative and positive anomalies over the period 1998-2015 (EPS > 0.85).
This strongly suggests that a common environmental factor is driving shell growth dynamics.
Unfortunately, the lack of long time-series of environmental parameters prevented us to identify
this factor. The main feature changing at an inter-annual time-scale is sea-ice dynamics, i.e. timingof freeze-up and break-up, ice thickness, etc. Sea-ice impacts underwater light availability and,
therefore, primary production dynamics by phytoplankton, microphytobenthos and ice-algae. This
could be the driving force underlying inter-annual variations in SGI shell chronology.

Session: Climate and Oceans: Past, Present and Future162

5th International Sclerochronology Conference, ISC 2019

Unlocking the archive: a biochronology repository
Elizabeth Tray1*, Deirdre Brophy1, Adam Leadbetter2, Niall O'Maoileidigh2
1
2

Marine and Freshwater Research Centre, Galway Mayo Institute of Technology, Galway H91 T8NW, Ireland
Marine Institute, Furnace, Mayo F28 PF65, Ireland*presenting author: Elizabeth.Tray@gmit.ie

The aim of the ARCHIVE project is to consolidate existing collections of fish scales, otoliths (earbones), associated images, and data into a single biochronology repository. Growth marks, genetic
material, and chemical constituents of fish scales and otoliths produce data that can be used toreconstruct temporal trends in biological responses of fish populations. These biological timeseries can be combined with long-term environmental data to develop robust statistical models
that predict species-specific population responses to a changing climate.
A common problem associated with biological collections is that while sample intake grows
exponentially, long-term storage is rarely a priority. Material is often collected to meet short-term
objectives and resources are seldom committed to maintaining and archiving long-termcollections. As a consequence, precious samples are frequently stored in many different andunsuitable locations, and may become lost or estranged from associated data.
The Marine Institute, Ireland (MI) holds over 10,000 scales and otoliths from salmon, trout andeel, with some collections dating back to the 1920’s. Samples are in different stages of image anddata processing. To consolidate these collections a multi-functional Drupal (open-source)
database is under development. The database contains two main schemas: (1) an archive fish scaleand otolith inventory and (2) a data analysis catalogue for researchers. Work-flows, data entry
sheets, and vocabulary lists that match the database will standardize the collection and storage offish scale and otolith samples. Biological material will be held within a sample repository andaccessed according to standard procedures for sample analysis and archive deposition. A public
view of the database will feature within the MI’s data catalogue, which is developed by the MI’s
Information Services & Development team. The ultimate aim is to produce Ireland’s first
repository that is centered around fish sclerochronology samples, paired with a database ofindividual growth records and scale and otolith images.
Unlocking the archive: using scale and otolith chronologies to resolve climate impacts (theARCHIVE project) is a collaboration between the Marine and Freshwater Research Centre at the
Galway-Mayo Institute of Technology and the Marine Institute in Ireland. The project (Grant-Aid
Agreement No. PBA/FS/16/03) is carried out with the support of the Marine Institute and is funded
under the Marine Research Programme by the Irish Government.

Session: Fisheries Ecology and Management163

5th International Sclerochronology Conference, ISC 2019

Oxygen isotope composition of Arctica islandica aragonite in
the context of shell architectural organization
Tamara Trofimova1*, Stefania Milano2, Carin Andersson1, Fabian G. W. Bonitz1,
Bernd R. Schöne3
1

NORCE Norwegian Research Centre AS, Bjerknes Centre for Climate Research, Jahnebakken 5, Bergen, Norway
Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6,
Leipzig, Germany
3
University of Mainz, Institute of Geosciences, J.-J.-Becher-Weg 21, Mainz, Germany
2*presenting author: tatr@norceresearch.noStable oxygen isotope composition of shell carbonate is one of the most studied and widely
applied proxy in bivalve sclerochronology. Stable oxygen isotope values are commonly used to
study paleotemperature and paleosalinity changes at high temporal resolution. Yet, thereproducibility of the results and the effect of microstructural organization on the isotopic
signature and measurements have not been extensively studied. In this study, we examine thearchitectural changes within Arctica islandica shells, specifically if samples from microstructurally
different shell layers typically used to produce paleorecords, differ in respect to stable oxygenisotope values. The oxygen isotope profiles of two microstructurally different shell layers, eachsampled at different temporal resolution, were compared to each other. Our results demonstratethat shell aragonite, collected from an inner portion of the outer shell layer (crossedacicular/lamellar microstructures), tends to be enriched in heavier oxygen isotopes compared tosamples from the outer portions (homogeneous microstructure). In some cases, this difference
exceeded 0.3‰, which may translate to 1.3oC difference in reconstructed temperatures. This
indicates that sampling from different microstructural layers can significantly affect the
reproducibility of the records and the interpretation of a recorded environmental signal. Observed
differences in stable oxygen isotope data may be associated with the physiology of the mollusk
and the physical and chemical composition of studied shell layers.

Session: Proxy Development: Challenges and Opportunities

1645th International Sclerochronology Conference, ISC 2019

Isotope chemistry of scales reveals continent-scale variation
in at-sea foraging in European populations of Atlantic
salmon
Clive Trueman1*, Kirsteen MacKenzie2, Jean-Marc Roussel3
1

Ocean and Earth Science, University of Southampton, UK
Havforskningsinstituttet, Tromsø, Norway
3
INRA Rennes, France
2*presenting author: trueman@noc.soton.ac.uk

Many marine animals return to coastal regions to breed or spawn. In these cases foraging
behaviour prior to breeding or spawning may be difficult to study and consequently poorly
understood. Sclerochronological approaches can offer valuable insights into these otherwise
obscure life history behaviours and the corresponding relationships between location,
environmental conditions and population dynamics.
Atlantic salmon are famed for their migration between open ocean foraging grounds and returnto natal rivers to spawn. Despite more than 100 years of scientific study, the nature of ocean
foraging within and among natal river populations has remained obscure, and this knowledge gap
is particularly pressing in the context of large scale increases in marine mortality of Atlantic overthe past 30 years.
Here we use the stable isotope composition of salmon scales recovered from c. 5000 salmon
returning to 10 European rivers from Scotland to Iberia over a 40 year time period, combined withpredictive models of the expected isotopic composition of salmon scales across the North Atlantic
to infer and compare foraging locations and dynamics of foraging location at continental anddecadal scales.
We find strong evidence for latitudinal effects in ocean foraging location, with fish returning tomore southerly rivers (S England, France) consistently foraging in more distant, colder waters thanfish returning to rivers in Northern Ireland and Scotland. Futhermore we find evidence fortemporally coincident changes in population-scale foraging location, presumably driven byenvironmental conditions, and for plasticity in foraging location within a single river and cohort.
We argue that diversity in foraging location within populations provides some buffering against
short-term ecological or environmental change, but salmon returning to rivers at the southern
margin of the species range show less diversity in foraging location and may have less resilienceto long term climatic change.
Spatial ecology is being revolutionised by smart tagging and genetic approaches, howeversclerochronological methods on samples from museum and laboratory collections remain the only
way to yield retrospective information on behaviour prior to return to coastal breeding areas inwidely dispersed animals at the scale of individual populations.

Session: Fisheries Ecology and Management165

5th International Sclerochronology Conference, ISC 2019

Potential for developing multispecies chronologies in the
Mediterranean Sea
Nicole Pavin1, Hana Uvanović2*, Carlotta Mazzoldi1, Ivica Vilibić2, Hrvoje
Mihanović2, Krešimir Markulin2, Tomislav Džoić2, Melita Peharda2
1
2

Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia*presenting author: uvanovic@izor.hr

Despite the increasing interest for developing multispecies chronologies using marine organisms,
this approach remains mostly underutilized, in particular for climate studies. This study is the firstattempt to develop bivalve multispecies chronology in the Mediterranean Sea. Samples of threelong living bivalve species were collected by SCUBA from two shallow (3-5 m) coastal sites in theeastern Adriatic Sea – Pag Bay and Živogošće. Sampling was conducted on several occasions in the
period from May 2014 to October 2016. Target species included commercially important Venerid
clam Callista chione and two large Glycymerid species – Glycymeris bimaculata and G. pilosa.
Although previous studies indicated that these species are common and locally abundant in theeastern Adriatic, a sufficient number of large sized individuals to enable chronology construction(older than 20 years) is obtained at both sampling sites only for G. bimaculata. For other two target
species, C. chione and G. pilosa, sufficient number of older individuals were collected only at Pag
and Živogišće sites, respectively. In laboratory, shell length, height, width and dry weight wasmeasured prior to embedding the shells in epoxy resin. Samples were cut along the axis of
maximum growth, ground, polished and etched in acid. Acetate peel replicas were prepared andphotographed with Zeiss microscope and camera. Image Pro Primer program was used to stichcomposite images and to measure increment widths. Visual crossdating of images was done bylist-year method and verified with program COFECHA. Dendrochronology software package
ARSTAN was used to construct the chronologies. At Pag, estimated age of oldest G. bimaculata
and C. chione were 23 and 29 years, respectively. Both species had synchronous growth within
populations, but there was no statistically significant correlation between their chronologies. AtŽivogošće, estimated age of the oldest G. bimaculata and G. pilosa were 52 and 61 years,
respectively, with intercorrelated chronologies. Bivalve chronologies were related to the mean
monthly seawater temperature and salinity. Mean monthly precipitation and monthly values ofabsolute dynamic topography (ADT) of the northern Ionian Sea were also analysed, to quantify
local vs. remote drivers of the bivalve growth. This study gives the basis for further investigationof bivalve multispecies chronologies in the Adriatic as well as other parts of Mediterranean Sea.
Research has been conducted in a framework of the project SCOOL (IP-2014-09-5747) supportedby the Croatian Science Foundation.

Session: Climate and Oceans: Past, Present and Future166

5th International Sclerochronology Conference, ISC 2019

Otolith chemistry of Greenland halibut – false hopes or an
opportunity to learn about population boundaries?
Mikko Vihtakari1*, Ole Thomas Albert1, Elvar H. Hallfredsson1, Alf Harbitz1,
Torild Johansen1, Kirsteen MacKenzie1, Erik Berg1, Jane A. Godiksen2
1
2

Institute of Marine Research, Fram Centre, Tromsø, Norway
Institute of Marine Research, Bergen, Norway*presenting author: mikko.vihtakari@gmail.com

Greenland halibut (Reinhardtius hippoglossoides) is a large deep-water flatfish species with acircumpolar distribution. The fish supports an important Arctic fishery with a total landed catch of
approximately 135 000 metric tons in 2017. Despite its importance, uncertainties remain
regarding its distribution patterns, biology, and population structure. Currently, the North Atlantic
fishery of Greenland halibut is managed as three separate stocks (i.e. regions). Results from markrecapture studies and genetics show, however, that the species migrate among the regions atsome point during their life cycle albeit the extent of these migrations is unknown. Ecologicallyinappropriate management routines increase the risk of local depletion with substantial
implications for the coastal communities in Greenland, Iceland, Faroe Islands, Norway, Russia, andeastern Canada.
A project initiated by the Institute of Marine Research (Norway) attempts to determine thepopulation boundaries of Greenland halibut in the Northeast Atlantic Ocean. The project contains
four work packages: 1) genetics, 2) mark-recapture analysis, 3) spatial structure in the survey andassessment data, as well as, 4) otolith morphology and geochemistry. In this poster, we present
the otolith morphology and geochemistry work package in a search for new collaborators,
laboratory possibilities and fresh scientific ideas to carry out the project. We intend to run traceelements and stable isotope analyses on otoliths from fish that were marked in Svalbard andcaught in Iceland. With this information, we hope to find the age when the fish migrated from one
stock management region to another. Further, we search for a multi-proxy "fingerprint" toseparate the geographic locations. The collected elemental information will be compared togenetics, mark-recapture data, and otolith morphology through shape analysis of the outer
contour of otoliths.

Session: Fisheries Ecology and Management167

5th International Sclerochronology Conference, ISC 2019

Otolith geochemistry of Diplodus puntazzo and Diplodus
vulgaris from marine waters and estuaries in the eastern
Adriatic Sea
Dario Vrdoljak1*, Hana Uvanović1, Regina Mertz-Kraus2, Sanja Matić-Skoko1,
Mišo Pavičić1, Melita Peharda1
12Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, Split, Croatia
Institute for Geosciences, Johannes Gutenberg University, 55099 Mainz, Germany*presenting author: vrdoljak@izor.hr

Studies of fish otolith geochemistry have contributed to the understanding of the life history,
segregation, connectivity and nursery identification of different fish species in many areas of theworld. Otoliths are calcified structures located in the inner ear of fish that are composed of calcium
carbonate. They represent archive of information on life histories in a chronological manner,
making it possible to retrieve information on environmental conditions experienced by individualﬁsh from hatching to capture. Otolith chemical signature in the core (young stage) may reflect
nurseries areas, while the edge (adult stage) could indicate the presence of geographic
management units. Differences in otolith geochemistry of sharpsnout seabream, Diplodus
puntazzo and two-banded seabream, Diplodus vulgaris, which inhabited coastal waters andestuary, were determined to evaluate movement patterns. Juvenile fish of D. puntazzo and D.
vulgaris were collected by beach seine net on two locations (estuary of river Pantan near Split andcove Sovlja near Šibenik) in the eastern Adriatic during June 2018. Upon collection fish were kept
frozen and transported to the lab were the length and weight of each specimen were measured,
the otoliths have been extracted, cleaned and prepared for transverse sections through the otolithcore with a low-speed saw. On the predetermined sections of otoliths with visible cores andgrowth marks, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used
to quantify concentrations of 12 chemical elements along maximum growth rates. Among them,Zn, Na, Mg, Sr, Ba, Mn, Li showed differences between the individuals and locations. Obtained
concentrations and peaks could be related to the different habitats and certain part of the otoliths
for each individual. The results represent the first geochemical study of Diplodus puntazzo and
Diplodus vulgaris otoliths in the Adriatic and reveal the potentials of this method for theinterpretation of ontogenetic movements. This work has been fully supported by Croatian Science
Foundation (HRZZ) under the project IP-2016-06-9884 (NurseFish).

Session: Fisheries Ecology and Management

168

5th International Sclerochronology Conference, ISC 2019

Were inoceramid chemosymbiotic bivalves?
Eric O. Walliser1*, Bernd R. Schöne2
1Institute of Geosciences, University of Mainz, Johann-Joachim-Becher-Weg 21, 55128 Mainz, Germany*presenting author: walliser@uni-mainz.de

Inoceramids are a group of extinct bivalves that flourished during the Late Cretaceous. Their shells
are often found in strata characterized by large amounts of pyrite and kerogen, weak/absent
bioturbation, and low faunal diversity. This mode of occurrence prompted some authors tosuggest a chemosymbiotic lifestyle for at least some inoceramid species. Yet, very little is still
known on the metabolism of this bivalve taxon. Here, we present high-resolution
sclerochronological data (δ13C, δ18O) obtained from shells of the USA, Japan, the Czech Republic,
and Italy, which provide a new insight into the physiology of the inoceramids. Shells of
Platyceramus platinus from the Santonian chalk deposits of the Western Interior Seaway (Kansas,
USA) exhibited δ13C values that resemble the typical 13C-enriched signal of modern
thioautotrophic bivalves. The ability to harbor sulfide-oxidizing bacteria also allowed inoceramids
to colonize cold seeps as indicated by the δ13C and δ18O values of Sphenoceramus spp. shells fromthe Campanian deposits of Hokkaido (Japan). In this regard, these inoceramids did not hostmethanotrophic bacteria and could not survive direct exposure to methane. However, achemosymbiotic lifestyle was not shared by all inoceramids as suggested by the near-equilibrium
δ13C and δ18O values of Inoceramus spp. from the Teplice Formation of the Czech Republic and the
Scaglia Rossa limestones of Northern Italy.

Session: Paleoecology and Evolution1695th International Sclerochronology Conference, ISC 2019

Constructing sclerochronology networks in the northwestern
Atlantic: A progress report
Alan Wanamaker1*, Nina Whitney1, Jared Ballew1, Ian Searles1, Caroline
Ummenhofer2, Bryan Black3, David Reynolds3
1

Iowa State University, Department of Geological and Atmospheric Sciences, Ames, IA, USA
Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole, MA, USA
3
University of Arizona, Laboratory of Tree-Ring Research, Tucson, AZ, USA
2*presenting author: adw@iastate.edu

The Gulf of Maine is a highly important and productive ecosystem that has experienced increasing
sea surface temperatures throughout the 20thcentury and it is considered highly susceptible tofuture warming. Recent warming in the Gulf of Maine is in part related to a decrease in thestrength of Atlantic meridional overturning circulation, which has been noted by several recent
studies. In the northwestern Atlantic, Labrador Sea derived water masses flow southward and mix
with northerly flowing sub-tropical waters (Gulf Stream, Warm Slope Water) in the mid-latitudes
and enter the Gulf of Maine system. Spatial and temporal heterogeneity is common in the marine
environment, especially along dynamic boundaries like the Gulf of Maine. Because of the strong
spatial variability along this oceanic transition zone and within the Gulf of Maine, it is unlikely thatone specific site would capture the full variability of the ocean conditions in this region throughtime. Hence, the development of a sclerochronological network is appealing. In this study, we
present multiple Arctica islandica master shell growth chronologies from the Gulf of Maine region
and explore the extent of the common signal during the instrumental period. Various statisticaltechniques (composite analysis, principal components analysis, spectral properties) were used to
explore extreme events, as well as the spatial and temporal coherence of these growth signals.
Our findings suggest that sclerochronological networks offer several advantages over single
chronologies such as reducing site-specific noise, better capturing the common signal over larger
spatial scales, and improved detection of large-scale environmental drivers.

Session: Climate and Oceans: Past, Present and Future170

5th International Sclerochronology Conference, ISC 2019

Reconstruction of bomb 14C in the North Sea derived from
Arctica islandica using Laser Ablation AMS
Christiane Yeman1*, Rob Witbaard2*, Marcus Christl1, Bodo Hattendorf3, Lukas
Wacker1, Hans-Arno Synal1
1

Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zürich, Switzerland
NIOZ, Netherlands Institute for Sea Research and Utrecht University, Department of Estuarine and Delta
Systems, PO Box 140, 4400 AC Yerseke, The Netherlands
3
Laboratory of Inorganic Chemistry, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
2*presenting author: rob.witbaard@nioz.nl

Arctica islandica shells can be used to derive time histories of radiocarbon (14C) across the northAtlantic. The annual resolution of the growth increments and the longevity makes the shell an
ideal climate archive for the reconstruction of 14C in the marine environment. Especially theidentification of the bomb pulse can be used for indirect 14C dating and as tracer of ocean
circulation. These applications find their limits in the sample preparation for AMS measurementsof carbonates which is time consuming, tedious and in need of a minimum amount of material. A
much faster way of analyzing carbonate samples for their radiocarbon content requiring lessmaterial is using a novel LA (Laser Ablation)-AMS technique. By focusing a pulsed laser beam (ArF
excimer laser 193 nm, 200 – 250 Hz) on the sample’s surface, a mixture of CO/CO2 is produced,
which is directly and continuously introduced into the gas ion source of the AMS. A positioning
system allows precise movement of the sample relative to the laser beam. Hence, scanning along
the shell margin of a specimen results in a continuous 14C profile. For the alignment of the LAradiocarbon data with the year of formation of the shell, an acetate peel is made of the analyzed
section with the laser tracks, visualizing the growth layers of the shell.
Here, we present continuous 14C records with 1-3 years resolution of individual specimens fromsix locations across the North Sea and northern Norway. All records comprise the marine
radiocarbon bomb pulse. The magnitude ranges from 10% to 30% compared to the atmosphericbomb pulse. This variability correlates to the sampling depth and location of the respective shell.
The data is in agreement with previously published 14C data from Arctica islandica in the North
Sea.

Session: Environmental Biomonitoring & Entrepreneurship

171

Prokurative, Split, Croatia
Photo by Filip Grubišić

Sponsors172

5th International Sclerochronology Conference, ISC 2019

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Institute of Oceanography and Fisheries
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University of Zadar
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Platinum sponsor
School of Medicine, University of Split
www.mefst.unist.hr175

5th International Sclerochronology Conference, ISC 2019Gold sponsor
Nu Instruments
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www.struers.com

176

5th International Sclerochronology Conference, ISC 2019
Silver sponsor
Stable Isotope Facility, UC Davisstableisotopefacility.ucdavis.edu

Silver sponsor

Silver sponsor

A.E. Lalonde AMS Laboratory

Marine Studies Group

www.ams.uottawa.ca

The Geological Society of London
www.geolsoc.org.uk/marine

177Institute of Oceanography and Fisheries, Split
Photo by Branko Dragičević