cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25850/nioz/7b.b.4
title: EGC-DrIFT drifter dataset Kulusuk deployment 2019

description: This dataset contains drifter data from an August 2019 deployment, at the east greenland shelfbreak, 65N. The netcdf file contains the positions, speeds, and measurements (Temperature and Salinity when available) of both CARTHE and SVP drifters.
DOI: 10.25850/nioz/7b.b.xd
title: Effects of offshore wind farms on suspended particulate matter derived from satellite remote sensing

description: The impacts of offshore wind farms on water quality remain to be quantified. This study examines the water quality in and around four offshore wind farms in the Dutch part of the North Sea using suspended particulate matter (SPM). Satellite-derived SPM was used in a Before-After-Control-Impact (BACI) analysis to assess changes in water quality caused by wind farm construction. In addition, relationships between satellite retrieved SPM and environmental variables from models (i.e., salinity, temperature and current velocity from the hydrodynamical GETM model, and wind speed from ERA-5 re-analysis meteorological data) were investigated to identify the drivers of SPM change in each of the four sites. Results show that SPM concentrations (as well as temperature and salinity) changed significantly when comparing a period of ca 6 years before and after wind farm construction, while no significant changes were observed when comparing control and impact treatment. The BACI analysis thus did not reveal a significant effect on SPM in response to construction of the wind farms. Scatterplots showed a complex interaction of hydrodynamic and meteorological variables on SPM changes, superimposed on a clear seasonal variation; when analysed by season, surface water temperature correlated most with SPM variations. Our results suggest that the combination of BACI and the visualization of satellite-derived and model derived data provide insight in the potential impact of wind farms. Satellite imagery was crucial in providing SPM data at relevant spatio-temporal scales; however, the satellite data may be biased by sampling under clear sky and low wind speed conditions, while the environmental variables were retrieved disregarding the wind farms in the hydrodynamical model. Despite these drawbacks, such information provides an understanding of the possible environmental impacts of offshore wind farms that can be used in policy making, and in general terms, these results may aid the planning of new wind farms.
DOI: 10.25850/nioz/7b.b.l
title: EMIR II - Southern North Sea porewater nutrients

description: Sediment pore water nutrients from coarse grained, southern North Sea sediments (2019-03-15).
DOI: 10.25850/nioz/7b.b.hg
title: Enhancing ecological complexity in soft-bottom coastal ecosystems: the impact of introducing hard substrates - Data

description: Coastal ecosystems globally face pressures, with natural coastal habitats being replaced by engineered structures. While hard structures for navigation-purposes and coastal defence can negatively impact native communities, they can also be applied in ecological restoration as artificial reefs to stimulate epibenthic species. This way substrates facilitate establishment of biogenic (shellfish) reefs and provide habitat heterogeneity in soft-sediment ecosystems. In a 1.5-year experiment, we introduced six different types of natural or biodegradable hard substrates in a subtidal soft-sediment system. We compared the substrates with surrounding soft sediment and evaluated differences between substrate types using biodiversity indices, community composition analyses and food web indicators. This offers a comprehensive understanding of how the introduced hard substrates affect ecosystem complexity. This dataset and the correspponding R-scripts were used for the statistics as presented in the paper. It contains a metadata file, and datafiles containing the following: sediment data, benthic species observed in the experiment, mobile species observed in the experiment. R scripts can be used to calculate biodiversity, community composition and food web metrics on the different types of substrates.
DOI: 10.25850/nioz/7b.b.m
title: Estuarine biofilm patterns: Modern analogues for Precambrian self-organization

description: This field and laboratory study examines whether regularly patterned biofilms on present-day intertidal flats are equivalent to microbially induced bedforms found in geological records dating back to the onset of life on Earth. Algal mats of filamentous Vaucheria species, functionally similar to microbial biofilms, cover the topographic highs of regularly spaced ridge???runnel bedforms. As regular patterning is typically associated with self-organization processes, indicators of self-organization are tested and found to support this hypothesis. The measurements suggest that biofilm-induced sediment trapping and biostabilization enhance bedform relief, strength and multi-year persistence. This demonstrates the importance of primitive organisms for sedimentary landscape development. Algal-covered ridges consist of wavy-crinkly laminated sedimentary deposits that resemble the layered structure of fossil stromatolites and microbially induced sedimentary structures. In addition to layering, both the morphological pattern and the suggested formation mechanism of the recent bedforms are strikingly similar to microbialite strata found in rock records from the Precambrian onwards. This implies that self-organization was an important morphological process in times when biofilms were the predominant sessile ecosystem. These findings furthermore emphasize that self-organization dynamics, such as critical transitions invoking ecosystem emergence or collapse, might have been captured in fossil microbialites, influencing their laminae. This notion may be important for paleoenvironmental reconstructions based on such strata.
DOI: 10.25850/nioz/7b.b.hd
title: Evaluation of the distributions of hydroxylated isoprenoidal GDGTs in Holocene Baltic Sea sediments for reconstruction of sea surface temperature: The effect of changing salinity

description: Hydroxylated glycerol dibiphytanyl glycerol tetraethers (OH-GDGTs) produced by both marine and freshwater thaumarchaea are increasingly used for the reconstruction of past sea surface temperature (SST). They occur throughout the modern Baltic Sea, but it is unknown if their OH-GDGTs can be used for assessing past SST in this area, where salinity has changed considerably over the Holocene. Three commonly applied OH-GDGT proxies for SST reconstruction, i.e., the OH-GDGT%, RI-OH, and RI-OH? indices, were tested using a Thaumarchaeotal culture enriched from the Baltic Sea grown at 4 and 22?C, and 12 surface sediments from the Baltic Sea and the adjacent Skagerrak. In the culture experiments all three proxies showed the expected response with the rise of temperature, but their absolute values were not always in line with existing marine core top calibrations, especially for the OH-GDGT% index. Of the two proxies based on the distribution of OH-GDGTs, the RI-OH index shows no increase with increasing mean annual SST, whilst the RI-OH? index shows only a linear correlation with SST when the sediments from the Bothnian Sea and Bay area, with a reduced salinity and increased lateral sediment influx, are omitted from the dataset. Two sedimentary Holocene records from the Arkona and Gotland basins were studied, the latter in high resolution. In the brackish phase of the Baltic Sea (the Littorina Sea stage), the RI-OH? index shows a good correlation with the TEX_86^( L), an established temperature proxy in the Baltic Sea, and can be used to identify important climatic events. However, during the preceding Ancylus Lake phase the RI-OH? (and RI-OH) index records far too high values, resulting in anomalously high SST estimates. This is probably because freshwater thaumarchaea adjust their OH-GDGTs differently, as has been shown for thaumarchaea in Lake Lugano?s water column. In the Littorina Sea, the Ancylus Lake and the Yoldia Lake phases of the Baltic basin, the record of the RI-OH? index, thus, most likely reflects both changes in temperature and salinity. Overall, our study indicates that a reduced salinity increases the values of the RI-OH? (and RI-OH) indices substantially and this should be considered when applying these proxies in other settings.
DOI: 10.25850/nioz/7b.b.u
title: Fe-binding ligands in Fram Strait and over the Northeast Greenland shelf - cruise PS100

description: There is a paucity of data on Fe-binding ligands in the Arctic Ocean. Here we investigate the distribution and chemical properties of natural Fe-binding ligands in Fram Strait and over the northeast Greenland shelf, shedding light on their potential sources and transport. Our results indicate that the main sources of organic ligands to surface waters of Fram Strait included primary productivity and supply from the Arctic Ocean. We calculated the mean total Fe-binding ligand concentration, [Lt], in Polar Surface Water from the western Fram Strait to be 1.65 ? 0.4 nM eq. Fe. This value is in between reported values for the Arctic and North Atlantic Oceans, confirming reports of north to south decreases in [Lt] from the Arctic Ocean. The differences between ligand sources in different biogeochemical provinces, resulted in distinctive ligand properties and distributions that are reflected in [Lt], binding strength (log K?) and competing strength (log ?) of ligands. Higher [Lt] was present near the Nioghalvfjerdsfjorden (79 N) Glacier terminus and in the Westwind Trough (median of [Lt] = 2.17 nM eq. Fe; log K? = 12.3; log ? = 3.4) than in the Norske Trough (median of [Lt] = 1.89 nM eq. Fe; log K?= 12.8; log ? = 3.8) and in Fram Strait (median of [Lt] = 1.38 nM eq. Fe; log K? = 13; log ? = 3.9). However, organic ligands near the 79 N Glacier terminus and in the Westwind Trough were weaker, and therefore less reactive than organic ligands in the Norske Trough and in Fram Strait. Our findings reveal the fundamental mechanism that underpin transport of dissolved-Fe (DFe) from the 79 N Glacier to Fram Strait, less reactive ligands will reduce Fe solubility. Accordingly, a portion of the glacial DFe will not be transported over the shelf into the ocean. The lower ligand binding strength in the outflow results in a higher inorganic Fe concentration, [Fe?], which is more prone to precipitation and/or scavenging than Fe complexed with stronger ligands. Ongoing changes in the Arctic and sub-Arctic Oceans will influence both terrestrially derived and in-situ produced Fe-binding ligands, and therefore will have consequences for Fe solubility and availability to microbial populations and Fe cycling in Fram Strait.
DOI: 10.25850/nioz/7b.b.6
title: Fe-binding ligands, TAN1504 and TAN1605

description: The governance of organic ligands in Fe availability for marine microbes has simultaneous effect on the biogeochemical cycling of trace metals and major nutrients, i.e. C and N. Investigating organic Fe speciation is of fundamental important to identify the processes regulating the dynamics of key ligand groups. Here we present organic Fe speciation along a transect covering the inner and outer shelf to open ocean, from the Hauraki Gulf in north-eastern of the North Island of New Zealand, which is sampled in two consecutive year during Autumn. The electrochemical approach, competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE-AdCSV) was applied. In the inner shelf, total ligand concentration ([Lt]) was ranged from 2.08 to 5.23 nM eq. Fe for both voyages, and explained by the various ligand sources in the inner shelf including primary production, the sediment flux and remineralization. At the shelf break, [Lt] was still relatively high ranged from 1.00 ??? 5.65 nM eq. Fe, with indication of post-bloom ligand sources in surface water, i.e. secondary production after a phytoplankton bloom. From the shelf-break further to open ocean, surface [Lt] was decreased (~0.6 ??? 2.7 nM eq. Fe) along with the decreased in surface primary production. The passive generation of ligands via bacterial remineralization of organic matter appears to be a ligand sources in the deep water &gt;500m from the shelf break toward the open ocean. Our result showed that the most variable excess ligands concentration ([L??], ~0.5 ??? 5 nM eq. Fe) was observed in surface water despite its oligotrophic condition. In the deeper water, [L??] was fairly static at 0.5 to 1 nM eq. Fe, with a higher complexation capacity relative to the surface water. This results could have further implication that complexation capacity of natural ligands determine the threshold of DFe concentration in the water column, especially at depth.
DOI: 10.25850/nioz/7b.b.5
title: Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula

description: Organic ligands are a key factor determining availability of dissolved-Fe (DFe) in the high nutrient low chlorophyll (HNLC) areas of the Southern Ocean. In this study, organic speciation of Fe is investigated along a natural gradient of the western Antarctic Peninsula, from an ice covered shelf to the open ocean. An electrochemical approach, competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE-AdCSV) was applied. Our results indicated that organic ligands in surface water on the shelf are associated with ice-algal exudates, possibly combined with melting of sea-ice. Organic ligands in deeper shelf water are supplied via resuspension of slope or shelf sediments. Further offshore, organic ligands are most likely related to the development of phytoplankton blooms in open ocean waters. On the shelf, total ligand concentrations ([Lt]) were between 1.2 nM eq. Fe and 6.4 nM eq. Fe. The organic ligands offshore ranged between 1.0 and 3.0 nM eq. Fe. The southern boundary of the Antarctic Circumpolar Current (SB ACC) separated the organic ligands on the shelf from bloom-associated ligands offshore. Overall, organic ligand concentrations always exceeded DFe concentration (excess ligand concentration, [L??] = 0.8 - 5.0 nM eq. Fe). The [L??] made up to 80% of [Lt], suggesting that any additional Fe input can be stabilized in the dissolved form via organic complexation. The denser modified Circumpolar Deep Water (mCDW) on the shelf showed the highest complexation capacity of Fe (??Fe??L ; the product of [L??] and binding strength of ligands, K??Fe??L). Since Fe is also supplied by shelf sediments and glacial discharge, the high complexation capacity over the shelf can keep Fe dissolved and available for local primary productivity later in the season upon sea ice melting.
DOI: 10.25850/nioz/7b.b.7
title: Fe-binding ligands, voltammetric methods comparison - PS100

description: Competitive ligand exchange ??? adsorptive cathodic stripping voltammetry (CLE-AdCSV) is a widely used technique to determine dissolved iron (Fe) speciation in seawater, and involves competition for Fe of a known added ligand (AL) with natural organic ligands. In this study three different ALs were used, 2-(2-thiazolylazo)-p-cresol (TAC), salicylaldoxime (SA) and 1-nitroso-2-napthol (NN). The total ligand concentrations ([Lt]) and conditional stability constants (log K??Fe??L) obtained using the different ALs are compared. The comparison was done on seawater samples from Fram Strait and northeast Greenland shelf region, including the Norske Trough, Nioghalvfjerdsfjorden (79N) Glacier front and Westwind Trough. Data interpretation using a one-ligand model resulted in [Lt]SA (2.72 ?? 0.99 nM eq Fe) &gt; [Lt]TAC (1.77 ?? 0.57 nM eq Fe) &gt; [Lt]NN (1.57 ?? 0.58 nM eq Fe); with the mean of log K??Fe??L being the highest for TAC (log K??Fe??L(TAC) = 12.8 ?? 0.5), followed by SA (log K??Fe??L(SA) = 10.9 ?? 0.4) and NN (log K??Fe??L(NN) = 10.1 ?? 0.6). These differences are only partly explained by the detection windows employed, and are probably due to uncertainties propagated from the calibration and the heterogeneity of the natural organic ligands. An almost constant ratio of [Lt]TAC/[Lt]SA = 0.5 - 0.6 was obtained in samples over the shelf, potentially related to contributions of humic acid-type ligands. In contrast, in Fram Strait [Lt]TAC/[Lt]SA varied considerably from 0.6 to 1, indicating the influence of other ligand types, which seemed to be detected to a different extent by the TAC and SA methods. Our results show that even though the SA, TAC and NN methods have different detection windows, the results of the one ligand model captured a similar trend in [Lt], increasing from Fram Strait to the Norske Trough to the Westwind Trough. Application of a two-ligand model confirms a previous suggestion that in Polar Surface Water and in water masses over the shelf, two ligand groups existed, a relatively strong and relatively weak ligand group. The relatively weak ligand group contributed less to the total complexation capacity, hence it could only keep part of Fe released from the 79N Glacier in the dissolved phase. Although the SA method had the lowest detection window compared to the TAC and NN methods, the SA method seemed to detect a wider view of the ligand groups.
DOI: 10.25850/nioz/7b.b.8
title: Field observations of HDPE pellets lost by MSC Zoe collected through citizen science via waddenplastic.nl by NIOZ and RUG.

description: Field observations, obtained through citizen science, collected via waddenplastic.nl, of washed-up HDPE pellets lost by container vessel MSC Zoe on 1 January 2019 north of the Dutch Wadden islands. Counts in number categories (0,1-10,11-100,&gt;100) within 0.4x0.4 m squares, typically on strand lines. Published in: doi: 10.3389/fmars.2021.607203
DOI: 10.25850/nioz/7b.b.qd
title: Food web interactions of breeding Arctic shorebirds are shaped by their elevational distribution: dataset

description: We describe the spatial position of little stints and red knots in the tundra food web, from both a top-down and a bottom-up perspective, and suggest that these affect shorebird diet and survival. The availability of the key food items for chicks is related to their diet, and, although it is not possible to fully disentangle cause and effect, we find support that the diet differences are explained by elevation. Moreover, the difference in the elevational distribution of shorebird nests impacts their relationships with predators.
DOI: 10.25850/nioz/7b.b.ff
title: Full EGC-DrIFT 6h interpolated dataset

description: This dataset contains drifter data from 5 deployments at the East Greenland shelfbreak, in 2019, 2020 and 2021. The deployments were done at the latitudes of : 65N (August 2019), 79N (September 2019), 60N (July 2020), 66N (August 2021) and 70N (August 2021). The netcdf file contains the positions, speeds, and measurements (Temperature and Salinity when available) of both CARTHE and SVP drifters. Drifter positions are interpolated every 6h from August 14th 2019 to November 15th 2022.
DOI: 10.25850/nioz/7b.b.gd
title: Great Skuas and Northern Gannets on Foula, summer 2022 - an unprecedented, H5N1 related massacre

description: In summer 2022, a highly pathogenic avian influenza virus (HPAIV) H5N1 pandemic struck, affecting numerous species of colonial seabirds all over the Northern Hemisphere. Great skuas Stercorarius skua and Northern Gannets Morus bassanus were especially badly affected by the outbreak. This report documents the exceptional mortality levels, poor reproductive success and a major population decline in Great Skuas breeding in Foula (Shetland), and a drop in numbers of breeding Northern Gannets on the island. Systematic searches (May-August) produced over 1500 corpses of Great Skuas of which 109 had been ringed earlier in life. The distribution of corpses was non-homogeneous, with clusters of corpses in relatively wet areas, mostly known as clubs and bathing sites. Mortality became apparent in early May, peaked in the second half of May and early June, but continued through the summer at lower levels. In June, Apparently Occupied Territories (AOT) of Great Skuas were counted and it appeared that numbers had declined by 57% since 2015, the most recent earlier survey (from 1820 to 778 AOT). Given the ongoing mortality in July and August, a decline in the order of magnitude of 60-70% in occupied territories is more likely. Great Skuas commenced breeding as usual in May and June, but most attempts failed, mainly because one or both partners got infected and died. The rapid spread of infections over Foula has probably been facilitated by the habit of Great Skuas to bath and socialise at freshwater lochs and pools; sites where close conspecific interactions occur and where all major pathways of infection could play a role: through accumulating of virions in water, aerosols shed from the respiratory tract, via dropped faeces, or by scavenging. How the gannets have picked up the virus is a mystery, but further infections in other marine birds and marine mammals indicate that the virus does cause problems in the marine environment. Gannets bred, but the population declined by 20% during the season (less dramatic than in other Scottish gannetries), while numbers of hatchlings were exceptionally low. Studying the epidemiology and transmission of avian influenza viruses in (pelagic) seabirds in marine habitats is critical to understand how and where outbreaks develop and spread.
DOI: 10.25850/nioz/7b.b.t
title: High current event at an Arctic deep-sea sponge ground

description: Deep-sea sponge grounds are hotspots of benthic biomass and diversity comparable to tropical coral reefs. So far very limited data exists on the range of environmental conditions deep-sea sponges and their accompanying fauna thrive in or which factors are driving their distribution and sustenance. Therefore we investigated oceanographic conditions at a deep-sea sponge ground located on the summit of an Arctic Mid-Ocean Ridge seamount. Hydrodynamic measurements were performed along CTD transects and a bottom lander was deployed within the sponge ground that recorded near-bottom physical properties as well as vertical fluxes of organic material over an annual cycle. The water column data demonstrated that the sponge ground is situated at the interface between two water masses. Internal waves on the interface interact with the seamount topography, and produce turbulent mixing and resuspension of organic material with temporarily very high current speeds up to 0.72 m s-1 near the seafloor. At the same time vertical movement of the water column delivers food and nutrients from water layers above and below towards the sponge ground. Only one major organic carbon flux event was observed during the year, providing fresh organic matter from the surface layers during the summer phytoplankton bloom period. The amount of organic matter sinking from the surface is likely not able to sustain the carbon demand of this ecosystem. Therefore the availability of dissolved matter, bacteria and nutrients and their delivery by tidal forced internal waves might play an important role in meeting their food demand.