Reconstruction of recent environmental change is important, especially in coastal areas such as the western Antarctic Peninsula, where rapid recent climatic change dramatically accelerates melting of tidewater glaciers and disintegration of coastal ice sheets. We are testing the applicability of the shellof the Antarctic soft‐shell clam Laternula elliptica as archive of change in near shore biogeochemistry, caused by glacial melting at the Western Antarctic Peninsula (WAP) during the last decades.Animals were collected at five pseudo random distributed stations located along the southern shoreline in the East of Jubany Station. This area is strongly impacted by sediment runoff originating from glacial catchment areas. Additional samples were taken at two reference stations located infront of the glacier snout and in the outer part of Potter cove opening into Maxwell Bay.Experiments on iron uptake and assimilation by L. elliptica were conducted to determine the pathways by which trace elements reach the shell. After 25 days of starvation animals were fed with iron enriched phytoplankton for another 25 days. During both periods five different tissues (mantle, gill, digestive gland, foot, siphon) and hemolymph were sampled regularly. Three short time experiments (10 14 d) were carried out, studying bivalve hemolymphatic cells as trace metal transporters and storage units. Dissolved (iron‐EDTA‐complex) and particulate (iron hydroxide) ironsupplementation was separately tested.Biogeochemical trace metal analysis will include ICP‐OES (inductively coupled plasma optical emission spectrometry) measurements of hemolymph and tissue samples, following acid digestion, as well as LA‐ICP‐MS (laser ablation inductively coupled plasma mass spectrometry) measurements of annual growth bands of the shells. Due to the small growth band dimensions, an analytical method offering high spatial resolution is needed. LA‐ICP‐MS constitutes the modern standard approach intrace element analysis of environmental archives. The results should demonstrate, whether different trace elements follow different routes of incorporation during calcification of the shell, which are controlled by the geochemical properties of the tracers. Furthermore these tests will show, if our hypotheses that the trace metal content in bivalve shells is linked to the glacial sedimentary input, can be approved or not.
Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 2: Coastal Change > WP 2.2: Integrating evolutionary Ecology into Coastal and Shelf Processes