Modification of Ca isotope and trace metal composition of the major matrices involved in shell formation of Mytilus edulis

• Published in: Geochemistry, geophysics, geosystems : G3 Vol. 9; no. 1; pp. Q01006 - n/a
• Main Authors: Heinemann, Agnes, Fietzke, Jan, Eisenhauer, Anton, Zumholz, Karsten
• Format: Journal Article
• Language: English
• Published: American Geophysical Union 01.01.2008; Blackwell Publishing Ltd
• Subjects: Biogeosciences; Biomineralization; Biosignatures and proxies; Brackish; Calcium; Calcium isotopes; Fluid dynamics; Fluid flow; Fluids; Isotopic composition and chemistry; Magnesium; Marine; Mytilus edulis; proxy; Strontium; trace elements; ANE, North Sea; ANE, Germany, Schleswig-Holstein, Kiel Fjord; ANE, Germany, Schleswig-Holstein, Schwentine Estuary; proxy; trace elements; calcium isotopes; biomineralization; Mytilus edulis
• ISSN: 1525-2027; 1525-2027
• DOI: 10.1029/2007GC001777

In this study we present the first combined investigation into the composition of the major matrices involved in calcification processes (surrounding water, extrapallial fluid, aragonite, and calcite) of Mytilus edulis with respect to their calcium isotope (δ44/40Ca) and elemental compositions (Sr/Ca and Mg/Ca). Our aim was to examine the suitability of Mytilus edulis as a proxy archive and to contribute to the understanding of the process of biomineralization. Mytilus edulis specimens were live collected from the Schwentine Estuary, Kiel Fjord, and North Sea (Sylt). δ44/40Ca was determined by thermal ionization mass spectrometry (TIMS) accompanied by measurements of Mg/Ca and Sr/Ca using inductively coupled plasma–optical emission spectroscopy (ICP‐OES). The elemental and isotopic compositions of the investigated matrices showed systematic offsets. The carbonates are strongly depleted in their magnesium and strontium concentrations and fractionated toward lighter calcium isotope compositions relative to the surrounding Schwentine Estuary water. The opposite is observed for the extrapallial fluid (EPF). Our findings extend the results of previous studies reporting a strong biological control and the interaction of different environmental conditions influencing biomineralization. Future studies should focus on the temporal development of the interrelation between the different matrices.