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  • 1
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    Isotope ratios, trace elements and ultrastructure results of Mytilus galloprovincialis shells and experimental site data off Ischia (Italy)
    PANGAEA
    In:  Supplement to: Hahn, Sabine; Rodolfo-Metalpa, Riccardo; Griesshaber, Erika; Schmahl, Wolfgang W; Buhl, Dieter; Hall-Spencer, Jason M; Baggini, Cecilia; Fehr, Karl T; Immenhauser, Adrian (2012): Marine bivalve shell geochemistry and ultrastructure from modern low pH environments: environmental effect versus experimental bias. Biogeosciences, 9, 1897-1914, https://doi.org/10.5194/bg-9-1897-2012
    Details
    Publication Date: 2023-05-12
    Description: Bivalve shells can provide excellent archives of past environmental change but have not been used to interpret ocean acidification events. We investigated carbon, oxygen and trace element records from different shell layers in the mussels Mytilus galloprovincialis combined with detailed investigations of the shell ultrastructure. Mussels from the harbour of Ischia (Mediterranean, Italy) were transplanted and grown in water with mean pHT 7.3 and mean pHT 8.1 near CO2 vents on the east coast of the island. Most prominently, the shells recorded the shock of transplantation, both in their shell ultrastructure, textural and geochemical record. Shell calcite, precipitated subsequently under acidified seawater responded to the pH gradient by an in part disturbed ultrastructure. Geochemical data from all test sites show a strong metabolic effect that exceeds the influence of the low-pH environment. These field experiments showed that care is needed when interpreting potential ocean acidification signals because various parameters affect shell chemistry and ultrastructure. Besides metabolic processes, seawater pH, factors such as salinity, water temperature, food availability and population density all affect the biogenic carbonate shell archive.
    Keywords: BIOACID; Biological Impacts of Ocean Acidification; Mediterranean Sea Acidification in a Changing Climate; MedSeA
    Type: Dataset
    Format: application/zip, 4 datasets
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    DATA PANGAEA
  • 2
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    (Table S1) Results of isotope analysis from shells of Mytilus galloprovincialis at the experimental site B1 and control site C
    PANGAEA
    Details
    Publication Date: 2023-05-12
    Keywords: East coast of Ischia, Italia; ES; Event label; HAND; Ischia_B1; Ischia_C; Mediterranean Sea Acidification in a Changing Climate; MedSeA; Mytilus galloprovincialis, distance from commissure; OS; Sample code/label; Sample type; Sampling by hand; δ13C; δ13C, standard deviation; δ18O, carbonate; δ18O, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 1190 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 3
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    (Table 1) Seawater chemistry calculated over the experiment period at the experimental site B1 and control site C
    PANGAEA
    Details
    Publication Date: 2023-05-12
    Keywords: Aragonite saturation state; Aragonite saturation state, standard deviation; Bicarbonate, standard deviation; Bicarbonate ion; Calcite saturation state; Calcite saturation state, standard deviation; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbon dioxide; Carbon dioxide, partial pressure; Carbon dioxide, partial pressure, standard deviation; Carbon dioxide, standard deviation; DEPTH, water; East coast of Ischia, Italia; ES; Event label; HAND; IP; Ischia_B1; Ischia_C; Ischia_harbour; Mediterranean Sea Acidification in a Changing Climate; MedSeA; OS; pH; pH, standard deviation; Sampling by hand; Temperature, standard deviation; Temperature, water; δ13C; δ13C, standard deviation; δ18O, maximum; δ18O, minimum; δ18O, standard deviation; δ18O, water
    Type: Dataset
    Format: text/tab-separated-values, 72 data points
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    DATA PANGAEA
  • 4
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    (Table 2) Thickness characteristics of different shell layers of Mytilus galloprovincialis at the experimental site B1 and control site C
    PANGAEA
    Details
    Publication Date: 2023-05-12
    Keywords: Comment; East coast of Ischia, Italia; ES; Event label; HAND; Ischia_B1; Ischia_C; Layer description; Mediterranean Sea Acidification in a Changing Climate; MedSeA; Mytilus galloprovincialis, layer thickness; OS; pH; Sampling by hand
    Type: Dataset
    Format: text/tab-separated-values, 131 data points
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    DATA PANGAEA
  • 5
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    (Table S2) Results of microprobe analysis maps (total area) of Mytilus galloprovincialis at the experimental site B1
    PANGAEA
    Details
    Publication Date: 2023-05-12
    Keywords: Barium; Barium, standard deviation; Calcium; Calcium, standard deviation; Chlorine; Chlorine, standard deviation; East coast of Ischia, Italia; ES; HAND; Iron; Iron, standard deviation; Ischia_B1; Magnesium; Magnesium, standard deviation; Manganese; Manganese, standard deviation; Mediterranean Sea Acidification in a Changing Climate; MedSeA; Phosphorus; Phosphorus, standard deviation; Sample code/label; Sampling by hand; Silicon; Silicon, standard deviation; Sodium; Sodium, standard deviation; Strontium; Strontium, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 357 data points
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    DATA PANGAEA
  • 6
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    Marine bivalve shell geochemistry and ultrastructure from modern low pH environments: environmental effect versus experimental bias (2012)
    PANGAEA
    Details
    Publication Date: 2024-03-15
    Keywords: Alkalinity, total; Animalia; Aragonite saturation state; Aragonite saturation state, standard deviation; Benthic animals; Benthos; Bicarbonate ion; Bicarbonate ion, standard deviation; Calcification/Dissolution; Calcite saturation state; Calcite saturation state, standard deviation; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, standard deviation; CO2 vent; Coast and continental shelf; Distance; East coast of Ischia, Italia; Elements; ES; Event label; Field experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; HAND; IP; Ischia_B1; Ischia_C; Ischia_harbour; Layer description; Mediterranean Sea; Mollusca; Mytilus galloprovincialis; North Atlantic; OA-ICC; Ocean Acidification International Coordination Centre; OS; Partial pressure of carbon dioxide, respiration, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Percentage; Percentage, standard deviation; pH; pH, standard deviation; Salinity; Sample code/label; Sample type; Sampling by hand; Shell length; Single species; Site; Species; Table; Temperate; Temperature, water; Temperature, water, standard deviation; Thickness; δ13C; δ13C, standard deviation; δ18O, carbonate; δ18O, maximum; δ18O, minimum; δ18O, standard deviation; δ18O, water
    Type: Dataset
    Format: text/tab-separated-values, 10106 data points
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    DATA PANGAEA
  • 7
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    Mapping of recent brachiopod microstructure: A tool for environmental studies (2018)
    Elsevier
    In:  Journal of Structural Biology, 201 (3). pp. 221-236.
    Details
    Publication Date: 2019-02-01
    Description: Shells of brachiopods are excellent archives for environmental reconstructions in the recent and distant past as their microstructure and geochemistry respond to climate and environmental forcings. We studied the morphology and size of the basic structural unit, the secondary layer fibre, of the shells of several extant brachiopod taxa to derive a model correlating microstructural patterns to environmental conditions. Twenty-one adult specimens of six recent brachiopod species adapted to different environmental conditions, from Antarctica, to New Zealand, to the Mediterranean Sea, were chosen for microstructural analysis using SEM, TEM and EBSD. We conclude that: 1) there is no significant difference in the shape and size of the fibres between ventral and dorsal valves, 2) there is an ontogenetic trend in the shape and size of the fibres, as they become larger, wider, and flatter with increasing age. This indicates that the fibrous layer produced in the later stages of growth, which is recommended by the literature to be the best material for geochemical analyses, has a different morphostructure and probably a lower organic content than that produced earlier in life. In two species of the same genus living in seawater with different temperature and carbonate saturation state, a relationship emerged between the microstructure and environmental conditions. Fibres of the polar Liothyrella uva tend to be smaller, rounder and less convex than those of the temperate Liothyrella neozelanica, suggesting a relationship between microstructural size, shell organic matter content, ambient seawater temperature and calcite saturation state.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    DOI: 10.1016/j.jsb.2017.11.011
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
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    Hydrothermal alteration of aragonitic biocarbonates: assessment of micro- and nanostructural dissolution–reprecipitation and constraints of diagenetic overprint from quantitative statistical grain-area analysis (2018)
    Copernicus Publications (EGU)
    In:  Biogeosciences (BG), 15 (24). pp. 7451-7484.
    Details
    Publication Date: 2021-02-08
    Description: The assessment of diagenetic overprint on microstructural and geochemical data gained from fossil archives is of fundamental importance for understanding palaeoenvironments. The correct reconstruction of past environmental dynamics is only possible when pristine skeletons are unequivocally distinguished from altered skeletal elements. Our previous studies show (i) that replacement of biogenic carbonate by inorganic calcite occurs via an interface-coupled dissolution–reprecipitation mechanism. (ii) A comprehensive understanding of alteration of the biogenic skeleton is only given when structural changes are assessed on both, the micrometre as well as on the nanometre scale. In the present contribution we investigate experimental hydrothermal alteration of six different modern biogenic carbonate materials to (i) assess their potential for withstanding diagenetic overprint and to (ii) find characteristics for the preservation of their microstructure in the fossil record. Experiments were performed at 175°C with a 100 mM NaCl + 10 mM MgCl2 alteration solution and lasted for up to 35 days. For each type of microstructure we (i) examine the evolution of biogenic carbonate replacement by inorganic calcite, (ii) highlight different stages of inorganic carbonate formation, (iii) explore microstructural changes at different degrees of alteration, and (iv) perform a statistical evaluation of microstructural data to highlight changes in crystallite size between the pristine and the altered skeletons. We find that alteration from biogenic aragonite to inorganic calcite proceeds along pathways where the fluid enters the material. It is fastest in hard tissues with an existing primary porosity and a biopolymer fabric within the skeleton that consists of a network of fibrils. The slowest alteration kinetics occurs when biogenic nacreous aragonite is replaced by inorganic calcite, irrespective of the mode of assembly of nacre tablets. For all investigated biogenic carbonates we distinguish the following intermediate stages of alteration: (i) decomposition of biopolymers and the associated formation of secondary porosity, (ii) homoepitactic overgrowth with preservation of the original phase leading to amalgamation of neighbouring mineral units (i.e. recrystallization by grain growth eliminating grain boundaries), (iii) deletion of the original microstructure, however, at first, under retention of the original mineralogical phase, and (iv) replacement of both, the pristine microstructure and original phase with the newly formed abiogenic product. At the alteration front we find between newly formed calcite and reworked biogenic aragonite the formation of metastable Mg-rich carbonates with a calcite-type structure and compositions ranging from dolomitic to about 80mol % magnesite. This high-Mg calcite seam shifts with the alteration front when the latter is displaced within the unaltered biogenic aragonite. For all investigated biocarbonate hard tissues we observe the destruction of the microstructure first, and, in a second step, the replacement of the original with the newly formed phase.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.5194/bg-15-7451-2018
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 9
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    Formation and mosaicity of coccolith segment calcite of the marine algae Emiliania huxleyi (2018)
    Wiley
    In:  Journal of Phycology, 54 (1). pp. 85-104.
    Details
    Publication Date: 2021-02-08
    Description: Coccolithophores belong to the most abundant calcium carbonate mineralizing organisms. Coccolithophore biomineralization is a complex and highly regulated process, resulting in a product that strongly differs in its intricate morphology from the abiogenically produced mineral equivalent. Moreover, unlike extracellularly formed biological carbonate hard tissues, coccolith calcite is neither a hybrid composite, nor is it distinguished by a hierarchical microstructure. This is remarkable as the key to optimizing crystalline biomaterials for mechanical strength and toughness lies in the composite nature of the biological hard tissue and the utilization of specific microstructures. To obtain insight into the pathway of biomineralization of Emiliania huxleyi coccoliths, we examine intracrystalline nanostructural features of the coccolith calcite in combination with cell ultrastructural observations related to the formation of the calcite in the coccolith vesicle within the cell. With TEM diffraction and annular dark-field imaging, we prove the presence of planar imperfections in the calcite crystals such as planar mosaic block boundaries. As only minor misorientations occur, we attribute them to dislocation networks creating small-angle boundaries. Intracrystalline occluded biopolymers are not observed. Hence, in E. huxleyi calcite mosaicity is not caused by occluded biopolymers, as it is the case in extracellularly formed hard tissues of marine invertebrates, but by planar defects and dislocations which are typical for crystals formed by classical ion-by-ion growth mechanisms. Using cryo-preparation techniques for SEM and TEM, we found that the membrane of the coccolith vesicle and the outer membrane of the nuclear envelope are in tight proximity, with a well-controlled constant gap of ~4 nm between them. We describe this conspicuous connection as a not yet described interorganelle junction, the “nuclear envelope junction”. The narrow gap of this junction likely facilitates transport of Ca2+ ions from the nuclear envelope to the coccolith vesicle. On the basis of our observations, we propose that formation of the coccolith utilizes the nuclear envelope–endoplasmic reticulum Ca2+-store of the cell for the transport of Ca2+ ions from the external medium to the coccolith vesicle and that E. huxleyi calcite forms by ion-by-ion growth rather than by a nanoparticle accretion mechanism.
    Type: Article , PeerReviewed
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    DOI: 10.1111/jpy.12604
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 10
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    Stable isotope profiles (Ca, O, C) through modern brachiopod shells of T. septentrionalis and G. vitreus: Implications for calcium isotope paleo-ocean chemistry (2010)
    Elsevier
    In:  Chemical Geology, 269 (3-4). pp. 210-219.
    Details
    Publication Date: 2017-12-07
    Description: Brachiopod shells are widely used as an archive to reconstruct elemental and isotopic composition of seawater. Studies, focused on oxygen and carbon isotopes over the last decades, are increasingly extending to the emerging calcium isotope system. To date, only little attention has been paid to test the reliability of fossil brachiopods on their modern counterparts. In this context, the present study investigates two modern brachiopods, Terebratulina septentrionalis (eastern Canada, 5–30 m depth, 7.1 °C seasonal temperature variation, two-layer shell) and Gryphus vitreus (northern Mediterranean, 200 m depth, constant all-year round temperature, three-layer shell). Both species were sampled along the ontogenetic growth direction and calcium, oxygen, and carbon isotopes as well as elemental concentration were measured. Calcium isotopes were analyzed on TIMS. The elemental composition was analyzed by LA-ICP-MS and ICP-AES. The results indicate an intra-specimen δ44/40Ca variation ranging from 0.16 to 0.33‰, pointing to a fairly homogenous distribution of calcium isotopes in brachiopod shells. However, in the light of the suggested 0.7‰ increase in calcium isotopes over the Phanerozoic such intra-specimen variations constrain ocean reconstruction. δ44/40Ca values of T. septentrionalis do not seem to be affected by growth rate. Calcium isotopic values of G. vitreus are heavy in the central part of the shell and trend towards lighter values in peripheral areas approaching the maximum isotopic composition of T. septentrionalis. The maximum inter-species δ44/40Ca difference of 0.62‰ between T. septentrionalis and G. vitreus indicates that care should be taken when using different taxa, species with different strontium content or brachiopods with specialized shell structure, such as G. vitreus, for ocean water reconstruction in terms of Ca isotopic composition. T. septentrionalis may record Ca isotopic fractionation related to seasonal seawater temperature variations in its shell but this is difficult to resolve at the current analytical precision. Average δ18O-derived temperatures of the two investigated species are close to on-site measured temperatures.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.chemgeo.2009.09.019
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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