BPT03-01

Room:104

Time:May 26 09:15-09:30

JpGU-EGU Biogeosciences Joint Session: aims and challenge
KITAZATO, Hiroshi1∗
1

Japan Agency for Marine-Earth Science and Technology

Since JpGU Biogeoscience Section was established on 2010, we are continuously holding international session in collaboration
with EGU. This session aims to discuss ecological and environmental information through geochemical data of proxy organisms,
such as calcifier or silicifier. We encourage to carry out both biological and goescientific approaches. I will shed light on
foraminiferal biodiversity and its application to environmental proxies.
Keywords: Biogeosciences, foraminifera, proxy, natural history, basic

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BPT03-02

Room:104

Time:May 26 09:30-09:45

Seasonal variation in genetic types of a planktonic foraminifer
UJIIE, Yurika1∗ ; UEDA, Hiroshi2
1

Department of Biology, Shinshu University, 2 Usa Marine Biological Institute, Kochi University

Planktonic foraminifers have been employed in paleoceanographic studies due to two major characters: wide geographic
distributions of species and chemical composition of their calcareous shells, which reflect temperature and chemistry of ambient
seawater. Accumulating phylogeographic knowledge, high genetic diversity of planktonic foraminifers has been known today
and these genetically isolated species are distributed in narrower geographic area than we expected. The previous studies reestablished temperature dependences of genetic types according to the pattern of their geographic distributions in many area.
Moreover, genetic differentiation among geographically distant populations examined the role of ocean currents in dispersal ofplanktonic foraminifers. In order to improve the use of planktonic foraminifers as ocean environmental indicators, understanding
ecological characters of genetic types is a crucial issue. In the previous studies for molecular phylogenetic analyses, living
specimens of planktonic foraminifers were collected at each site as occasion arises. The present study therefore collected samples
every month for 1 and half years at same location, the Tosa Bay, where the branch of the Kuroshio Current reaches. We focused on
Globigerinoides ruber , the most commonly used species for paleoceanography, and found this morphospecies during the wholeyears in the study area. Four genetic types are detected throughout our survey, though the frequency of each type varied at eachsampling time. We demonstrate the effect of external environment to productivity of planktonic foraminifers by analyzing therelationship among water-temperature, chlorophyll concentration, and frequency of genetic types. We furthermore test whether
the distance from the main path of the Kuroshio Current is efficiently caused to transport a population of specific genetic type.
These examinations provide us the exact information to address seasonal variation of planktonic foraminifers at genetic-type
level.
Keywords: time-series collection, planktonic foraminifer, genetic type, ecological feature

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BPT03-03

Room:104

Time:May 26 09:45-10:00

Cryptic diversity in planktonic foraminifera and the relationship between molecular andmorphological classification
WEINER, Agnes1∗ ; KITAZATO, Hiroshi2 ; KUCERA, Michal1
1

MARUM, University of Bremen, 2 JAMSTEC

Planktonic foraminifera are marine single celled eukaryotes that are found globally in the ocean. They construct calcite shellsthat accumulate in the sediment and are used for micropaleontological studies to reconstruct past climate conditions. Modern
planktonic foraminifera have been classified into about 40 species on the basis of morphological characteristics of their calcite
shell. Molecular investigations however uncovered an unexpectedly high cryptic genetic diversity within these morphospecies,
implying that their biodiversity has been largely underestimated. These cryptic species show distinct biogeographic distribution
patterns and ecological adaptations. Therefore, understanding the extent of genetic diversity within a morphospecies as well as
the ecological adaptations of its cryptic species is highly important in order to enhance the applicability of foraminifera as proxies
in micropaleontological studies. We are applying a single cell approach to survey the extent of cryptic diversity within the SSU
rDNA of individual morphospecies and to examine the biogeography, habitats and ecological adaptations of cryptic species. In
addition, we are trying to establish a connection between genetic diversity and morphological variability of the calcite shells bymorphometric analysis in order to taxonomically revise the morphospecies and to create a connection between living specimens
and the fossil record.

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BPT03-04

Room:104

Time:May 26 10:00-10:15

A fundamental function of calcareous spine of large benthic foraminifers for lighting
insideISHITANI, Yoshiyuki1∗ ; CUSACK, Maggie1
1

School of Geophysical and Earth Science, Glasgow University

Major groups of foraminifers precipitate calcium carbonate and form calcareous shells with unique and complicate structure.
One characteristic structure is a spine, covering the exterior surface of the shells. These shells and spines are though to have afunction for the protection of the cell from predators or for the prop to extend the pseudopodia. However, in other organisms(e.g., land plants), calcareous crystals play a role for increasing light intensity into the photosynthetic tissue more efficiency byscattering light. Our question is what are ecological functions of the shell and spines of calcareous crystals in foraminifers.
Large benthic foraminifers (e.g., Calcarina ) are the dominant species in the tropical reef waters, where is under exposureof strong light with nutrient depletion. They harbor a vast amount of photosynthetic symbionts inside the cell and utilize these
symbionts for uptake recycle-nutrients to survive in the oligotrophic waters. Morphologically, Calcarina have blunt spines, which
help to spread the pseudopodia, extended in a single circle round a central axis. Their pseudopodia attach to the basement, andavoid to be flowed over by tidal wave. However, our knowledge to ecological function of calcareous spines of Calcarina is still
limited. We investigated the crystal orientation of calcareous spines of Calcarina gaudichaudii by using Electron Back Scatter
Diffraction (EBSD) analysis. Calcareous crystals are arranged horizontally to the axis of the spine in the center and graduallyvent to the edge. This orientation of calcareous crystals makes a pathway of light through spines to the interior of the shell.
Our finding suggests that calcareous spines of C. gaudichaudii have ecological function to focus light into the cell and promote
photosynthesis of their harboring symbionts.

Keywords: Calcarina, calcareous, Electron Back Scatter Diffraction analysis

1/1BPT03-05

Room:104

Time:May 26 10:15-10:30

Functional analysis of shell proteins using transgenic pearl oysters
ZHAO, Ran1∗ ; ENDO, Kazuyoshi11Dept of Earth and Planetary Sciences, University of Tokyo

For the study of biomineralization, the mollusc Pinctada fucata is arguably an attractive genetic model system, with its draft
genome sequence having been deciphered recently. It produces two crystallographically different shell layers, including theindustrially important nacreous layer. We are interested in developing knock-out pearl oysters to analyze the functions of shell
matrix proteins, the key players in biomineralization processes, including the unusually acidic protein Aspein. In this study, thewidely used Minos transposon system is applied to generate insertional mutagenesis. The first step in developing transposons as
tools for mutagenesis is to demonstrate their mobile elements function efficiently and stably in the target organism. Therefore,
green fluorescent protein (GFP) is integrated into the transposon to reflect its efficiency.

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BPT03-06

Room:104

Time:May 26 11:00-11:15

Morphological observation of cytoplasm with acidic and alkaline vesicles in large foraminifera
cell by confocal imaging
OHNO, Yoshikazu1∗ ; FUJITA, Kazuhiko2 ; TOYOFUKU, Takashi3 ; NAKAMURA, Takashi1
1Graduate school of Engineering and science, University of Ryukyus, 2 Department of Physics and Earth Sciences, University of
Ryukyus, 3 Institute of Biogeosciences (BioGeos), Japan Agency for Marine-Earth Science and Technology
Algal symbiont-bearing large benthic foraminifers are primary and carbonate producers as well as paleoenvironmental indicators in tropical and subtropical reef environments. Despite their importance, their cellular physiology is not well known. In
the present study, we have developed methods to observe in vivo images of a living symbiotic porcelaneous large foraminifer,
Amphisorus kudakajimensis. The Nikon A1 confocal laser scanning microscope with Calcein-AM was used as a fluorescent indicator for visualizing the morphology and streaming of cytoplasm in living A. kudakajimensis. The observations indicated thatthe cytoplasmic density decreased and reticulopodia were formed at the aperture in the marginal part of intrashell cytoplasm. We
also observed vesicles with elevated pH (pH 9.0) and lowered pH (pH 6.0) in reticulopodia-like cytoplasms using a pH-sensitive
probe molecule, 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS). The present study demonstrates the use of confocal microscopy
in studying cytoplasmic dynamics and the initial calcification processes such as seawater endocytosis and alkalization of seawatervacuoles.
Keywords: Large foraminifera, Confocal imaging, Live imaging, pH, Calcification

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BPT03-07

Room:104

Time:May 26 11:15-11:30

Calcification mechanisms in foraminifera and proxy incorporation
BIJMA, Jelle1∗ ; NEHRKE, Gernot1 ; RAITSCH, Markus1 ; DE NOOIJER, Lennart2 ; FUNCKE, Antje1 ;KEUL, Nina3
1

Marine Biogeosciences, Alfred Wegener Institute, 2 Marine Geology, Royal NIOZ, 3 Biology and Paleo Environment, LamontDoherty Earth Observatory
Calcifying organisms, such as pteropods, bivalves, corals and foraminifera provide a rich resource for pale-oceanographers and?climatologists because their geochemical make-up (proxies) can be used to reconstruct past ocean history and evolution during
and after natural carbon perturbations. However, it has been shown for all geochemical proxies that the main assumption of only
one environmental variable controlling a target proxy is too simple. Empirical calibrations introduce a lot of uncertainty because
the mechanisms of proxy incorporation are not well understood. The major problem is that the calcification mechanisms are stilla black box. In this presentation I will review our current understanding of calcification and proxy incorporation in foraminifera,
specifically with respect to the impact of carbonate chemistry and the new opportunities arising from this.
Keywords: Calcification, proxy1/1

BPT03-08

Room:104

Time:May 26 11:30-11:54

Minor element partitioning and mineralogy in limpets from a CO2 vent site
NEHRKE, Gernot1∗ ; LANGER, Gerald2 ; SADEKOV, Aleksey2 ; BAGGINI, Cecilia3 ;RODOLFO-METALPA, Riccardo4 ; HALL-SPENCER, Jason3 ; BIJMA, Jelle1 ; ELDERFIELD, Henry2
1

Biogeosciences, Alfred-Wegener-Institut, 2 University of Cambridge, 3 School of Marine Science and Engineering, Universityof Plymouth, 4 CoReUs, IRD, Centre IRD de Noumea
Specimens of the patellogastropod limpet Patella caerulea were collected within and outside a CO2 vent site at Ischia, Italy.
The shells were sectioned transversally and scanned for polymorph distribution by means of confocal Raman microscopy. Minor element to calcium ratios were measured using laser-ablation-inductively-coupledplasma-mass-spectroscopy (LA-ICPMS).
Mg/Ca, Sr/Ca, and Li/Ca ratios were determined in calcitic as well as aragonitic parts of the shells. This approach allows forinvestigating the effects of the polymorph and the seawater carbonate chemistry on minor element partitioning separately.
Keywords: calcification, proxy, CO2, mineralogy, patellogastropod limpet

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BPT03-09

Room:104

Time:May 26 11:54-12:09

Mathematical analysis of proton, carbon, and calcium transport during calcification process of benthic foraminifera
MATSUO, Miki Y.1∗ ; TOYOFUKU, Takashi1 ; SAKAGUCHI, Hide1 ; DE NOOIJER, Lennart J.2
1

Japan Agency for Marine-Earth Science and Technology, 2 Utrecht University

Foraminifera are marine unicellular organism responsible for approximately 50% of today’s ocean calcium carbonate production, which implies that they play a considerable role in the global carbon cycle in ocean chemistry. However, we have not fully
understood how their calcifications proceed and change their chemical environment.
To understand the calcification process, we investigate the dynamics of the pH around the foraminifer. The visualized spatial
pH distribution shows that the calcification accompanies a rapid decrease of the surrounding pH, which implies that the calcification accompanies active proton pumping. The resultant spatial pH distribution is used to estimate the flux of proton releasedout of the protective envelope. Combing the estimated proton flux and the calcium carbonate responsible for a new chamber, we
propose that the proton/H+ exchange process is the key process driving the foraminiferal calcification.

Keywords: benthic foraminifera, calcification, proton transport, mathematical analysis

1/1BPT03-10

Room:104

Time:May 26 12:09-12:24

An experimental approach to understand trophic interaction of photosymbiosis in planktic
foraminifers
TAKAGI, Haruka1∗ ; KIMOTO, Katsunori2 ; FUJIKI, Tetsuichi2 ; HIRANO, Hiromichi3
1

CSE Grad. School, Waseda University, 2 Japan Agency for Marine-Earth Science and Technology, 3 Dep. Earth Sciences, Sch.
Education, Waseda University

Planktic foraminifers are marine heterotrophic protists. Of about 50 species of modern planktic foraminifers, about 10 species
that especially dominate in warm and low-nutrient surface water harbor autotrophic algae as endosymbionts (photosymbiosis).
It is generally considered that foraminifers benefit from photosynthates of symbionts, and in return, they provide nutritious environment for symbionts to live. At the same time, however, the host’s degree of dependence on symbionts is still enigmatic. Thisis because growth of the host primarily depends on food (prey) availability. In this context, a common assumption that photosymbiosis is an advantageous ecology for host foraminifers to live in oligotrophic oceans still has room to discuss. To understandtrophic interaction between host and symbionts, we conducted culture experiments and analyzed vitality of host-symbiont consortia under controlled nutrient conditions.
We cultured dinoflagellate-bearing species Globigerinoides sacculifer for two weeks. Assuming the two sources of nutrientsfor symbionts, i.e., from the host’s metabolites and from the ambient seawater, we controlled feeding regime (fed Artemia every other day or unfed) and nutrient concentration of culture media (0.22-µm filtered seawater [SW] or nutrients-added filteredseawater [NSW]). Four experimental groups are set; (a) fed and SW, (b) unfed and SW, (c) fed and NSW, and (d) unfed and
NSW. Nutrient concentrations of SW and NSW were respectively 0.2 and 16 µmol L−1 of NO3 +NO2 , and 0.07 and 1.0 µmol
L−1 of PO4 . Temperature was set to 26.5-27.5 ℃. Photosynthetic active radiation was set to 170-220 µmol quanta m−2 s−1 ,and its light/dark cycle was 14/10 hours. Test growth of the host, chlorophyll content, and photo-physiology of the symbionts
were used as criteria of their vitality. We measured maximum test length of host foraminifers and chlorophyll fluorescence ofindividual host-symbiont consortium during the culture period almost every day. For fluorometric analysis, we used fast repetition rate (FRR) fluorometry. From FRR measurement, F m (an index of chlorophyll content), and F v /F m (an index of potential
photosynthetic activity) were obtained and analyzed for each individual consortium.
During the culture period, foraminifers grew and formed new chambers in the fed groups (a, c). On the contrary, specimens
in the unfed groups (b, d) gradually decreased their cytoplasm volume, and in accordance with the decrease they often shedchambers one by one. The chlorophyll content, thus the biomass of symbionts per foraminifer, tended to increase in the fed
groups (a, c), whereas it decreased or kept nearly constant in the unfed groups (b, d). Despite the apparent diminishment of
the unfed groups, F v /F m was significantly higher in the unfed groups (b, d) than that in the fed groups (a, c). It indicates thatsymbionts in starved foraminifers photosynthesized more actively. Nutrient concentration in the culture media (SW or NSW) did
not necessarily affect on F v /F m .
Considering the fact that foraminifers maintained their life and symbionts were capable of photosynthesis in starved condition,
it can be said that foraminifers have survived only by photosynthates derived from the symbionts or digesting the symbionts
themselves for about two weeks of the culture period. If this relationship is true in natural environment, photosymbiotic interaction should help foraminifers to survive for certain duration even if they cannot capture any prey. This should be an advantage
for them to live in low-nutrient and well-lit environment.
Keywords: planktic foraminifers, photosymbiosis, nutrients, FRRF, culture

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BPT03-11

Room:104

Time:May 26 12:24-12:39

Strong typhoon in 2005 recorded in the shell growth lines and geochemical signals of T.
maxima from Okinotori Island
KOMAGOE, Taro1∗ ; WATANABE, Tsuyoshi1 ; MIYAJI, Tsuzumi2 ; SHIRAI, Kotaro3 ; YAMAZAKI, Atsuko3
1

Department of Natural History, Graduate School of Science, Hokkaido Univ., Sapporo, Japan, 2 Tomakomai City Museum,Tomakomai, Japan, 3 Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, JapanThe giant clam (Tridacnidae ) widely distributes over the coral reefs in Indo- Pacific oceans and forms the largest shells inbivalves. The giant clam has symbiotic algae, facilitating fast growth rate and forming daily shell growth patterns. By measuring
and counting the daily growth lines, we can know exactly when the daily growth lines were deposited. This growth pattern analysis is useful for reconstruction of the past environments at daily resolution. The aim of this study was to validate whether the shellof the giant clam (Tridacna maxima ) in Okinotori Island, the southern edge island in Japan, could record daily environmental
events such as typhoons.
The shell samples were collected alive in Okinotori Island on 5th Jun 2006. The shells were cut into two slices along the maximum growth axis. The number and interval width of microgrowth lines were measured under a digital microscope (KYENCE
VHX-2000). Sub-sampling for oxygen stable isotope measurements were performed along the growth direction on another sliceof the shell by using dental drill. The powder samples were introduced to carbonate preparation device (Kiel Device Ⅳ), andthe produced CO2 was analyzed by a stable isotope ratio mass spectrometer(Thermo Scientific MAT253). Stable oxygen isotope
ratios (δ 18 O) were compared with sea surface temperature (SST) and maxima values were assigned the lowest SST in February.
The correspondence between reconstructed SST and daily observed SST indicated that the microgrowth lines were formed daily
basis. Growth disturbances were observed as v-shaped breaks in the shell outer layers. The high δ 18 O peaks corresponded withthese growth disturbances suggested that this specimen recorded the strong typhoon in Okinotori Island on 3th September 2005.
Trace element analysis using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) (Agilent 7700) with
100µm and 30µm spots (Mg, Ca, Mn, Sr, Ba) revealed that the specimen has Ba/Ca positive peaks as an after-signature of strong
typhoons. Moreover, the significant positive peaks observed in Ba/Ca profile suggested the upwelling events due to typhoons in
Okinotori Island.
These results indicated that sclerochronological and geochemical record in giant clam shells could be useful for reconstructionof past typhoon events.
Keywords: Giant clam, Oxygen isotope, Carbon isotope, Trace elements, Growth line

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BPT03-12

Room:104

Time:May 26 14:15-14:40

Effects of recent ocean acidification in the western North Pacific on Porites coral calcification
KUBOTA, Kaoru1∗ ; YOKOYAMA, Yusuke1 ; ISHIKAWA, Tsuyoshi2 ; SUZUKI, Atsushi3 ; ISHII, Masao4
1

Atmosphere and Ocean Research Institute, The University of Tokyo, 2 Japan Agency for Marine-Earth Science and Technology,
National Institute of Advanced Industrial Science and Technology, 4 Meteorological Research Institute, Japan Meteorological
Agency3

One third of carbon dioxide emitted to the atmosphere as a result of human activities has been incorporated by the surface
ocean. Subsequently, the seawater is acidifying at an unprecedentedly faster rate (ocean acidification); seawater pH (pHSW ) has
declined by ˜0.1 since the Industrial Revolution (1750 AD). As a pHSW decline reduce saturation state of calcium carbonate, itwill probably lead to severe consequences for scleractinian corals, important reef builders in the tropical and subtropical oceans.
Up until now, many studies have evaluated effects of ocean acidification on scleractinian corals through culturing experiments,
but few studies evaluated it in the natural environment. To better understanding how corals and coral reef ecosystems will adapt
to or be damaged by the resulting changes in environments, field observations are crucial. Using thermal ionization mass spectrometry, we measured a 100 year record of boron isotopes (δ 11 B) of massive Porites coral obtained from Chichijima, Ogasawara
Archipelago, western North Pacific. The result revealed a raid decline of δ 11 B since 1960 (-0.17 ± 0.07 ‰/decade), suggestinga decrease of pH of extracellular calcification fluid (pHCF ) due to ocean acidification. The result also showed that pHCF has
been decreasing rapidly (changing sensitively to pHSW ) than estimation from culturing experiments of Porites corals. Thus itsuggests the calcification fluid of Porites coral become corrosive to aragonite in the future (pHCF = ca. 8.3 when pHSW = ca. 8.0
in 2050) at an earlier point than previously expected, despite the pHCF up-regulation mechanism of corals. Therefore, it is likelythat ocean acidification has already had negative influences on corals in addition to various environmental stressors represented
by regional warming.
Keywords: boron, coral, Porites, ocean acidification, calcification

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BPT03-13

Room:104

Time:May 26 14:40-14:55

Proton Management of Foraminiferal Calcification
TOYOFUKU, Takashi1∗ ; DE NOOIJER, Lennart jan2 ; FUJITA, Kazuhiko4 ; SHIRAISHI, Fumito3 ;REICHART, Gert-jan2 ; KITAZATO, Hiroshi1
1

JAMSTEC, 2 NIOZ, 3 Hiroshima University, 4 Universoty of Ryukyus, 5 Utrecht University

Marine calcification plays an important role in the global carbon cycle. Currently, approximately half of all carbon buried in theseafloor is the result of biogenic calcium carbonate production. Perforate foraminifera are a prime example of marine carbonate
producers and responsible for a large portion of today’s production. The physiological processes involved in calcification, however, are still unclear. Here we present some results on the intra- and extracellular pH changes in benthic perforate foraminifera
during calcification. These observations allow for calculating the budgets of ion fluxes that are taken up and removed from thecalcification space, which are placed in the context of previously obtained results and published calcification models to constructa unifying model for perforate foraminiferal calcification. This model also accounts for general patterns in observed fractionation
factors of various elements.
Keywords: foraminifera

1/1BPT03-14

Room:104

Time:May 26 14:55-15:10

Inorganic precipitation mechanism of calcium carbonate polymorphs and their precursors
KAWANO, Jun1∗
1Creative Research Institution, Hokkaido University

Calcium carbonate, CaCO3 , occurs in six different forms: three crystalline polymorphs (calcite, aragonite, and vaterite), twohydrate phases, and amorphous calcium carbonate (ACC). These polymorphs are important both in life and material sciences,
especially the occurrence of CaCO3 in living organisms has received considerable attention. As a basis for understanding biomineralization, inorganic precipitation mechamism of these polymorphs has been extensively investigated for over a hundred years.
Recently, crystallization pathway through non-classical mechanism such as stable prenucletaion cluster aggregation has been
proposed, which give a new picture of the early stages of calcium carbonate growth. However our knowledge of formation
process of CaCO3 , especially that of the mechanism of polymorph selection, is far from complete.
We have investigated experimentally and theoretically the metastable formation of CaCO3 polymorphs and their precursors.
In particular, the effect of Mg2+ on the nucleation and growth of CaCO3 polymorphs has been focused and the quantum chemical calculations of Mg-containing CaCO3 surfaces and clusters appearing in the early stages of CaCO3 formation have been
performed. As a result, Mg2+ substituted for Ca2+ affects the structure of surfaces and clusters, and may have significant effecton the polymorph selection of CaCO3 . In this presentation, we will report our results in detail based on the recent progress inthis field.
Keywords: calcium carbonate, metastable phase, precursor

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BPT03-15

Room:104

Time:May 26 15:10-15:35

Mesoscopic textures of biogenic and biomimetic calcite crystals
IMAI, Hiroaki1∗ ; MIYAJIMA, Ryoichi1 ; OAKI, Yuya1 ; KOGURE, Toshihiro2
1

Faculty of Science and Technology, Keio University, 2 Graduate School of Science, The university of Tokyo

The mesoscale granular textures having a single crystalline feature are generally observed on the continuous body of various
biogenic and biomimetic calcite crystals. The distribution of the organic phase and lattice strain in the textured crystals vary withorganism species or the growth conditions. The prismatic layer of a fan mussel, A. pectinata, exhibits a relatively homogeneous,
low-strain texture consisting of the nanoscale grains with discrete organic inclusions; the prism structure of a pearl oyster, P.
fucata, and an avian eggshell have a high-strain granular texture with localized organic phases. A variety of the mesoscopic
textures similar to the biogenic calcite crystals are artificially produced in a supersaturated solution containing specific organic
molecules. The high-strain textures were produced through mesoscopic dendritic growth of calcite by physical impedance of arigid gel matrix and subsequent thickening of the branches. Continuous growth of the crystal involving nanoscale segregation ofsoluble polymers would result in the formation of the low-strain body having mesoscopic textures. The chemical durability of
the low-strain biogenic and biomimetic textured calcites are enhanced by the combination of the inorganic crystal and the organic
molecules.
Keywords: Biomineral, Calcium carboate, Mesocrystal

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