Seminar

Past ocean conditions have been revealed using different proxies. Marine shells of crustaceans such as ostracod valves have been successfully used to reconstruct past temperature and salinity. However, its utility is limited by different factors including inter-species and instar variability, shell preservation and cleaning methods that could eventually affect the biogenic chemical composition. Here, we study an ostracod species, Sinocytheridea Impressa, which is commonly found in Asian coastal waters. Shells are analyzed under different techniques, including Flow Through - Time Resolve Analysis (FT-TRA), Electron probe micro-analysis (EPMA) and Inductively Couple Plasma Mass Spectrometry (ICP-MS) in order to evaluate the trace element distribution and concentration variability. Our results suggest that some Element/calcium ratios (E/Ca) are potentially affected by shell preservation and are not homogeneously distributed across the shell. In addition, the type of cleaning can affect E/Ca ratios, but there is no statistical different between juveniles A-1 and adults ostracods. These results show that the utility of ostracod shells as a paleo-indicator of marine conditions could be potentially limited by preservation, cleaning method and its internal chemical variability.