Δ14C and δ13C Variations in Organic Fractions of Baltic Sea Sediments

This article investigates variations of Delta C-14 and delta C-13 of total organic carbon (TOC) in sediments as well as in humic acids, lipid, and phospholipid fractions isolated from the surface (0-3 cm) sediment samples collected in the Curonian Lagoon and in the Baltic Sea. This study was performed to estimate relative contributions of the marine and terrestrial inputs to organic carbon in sediments, to assess a possible effect of petroleum hydrocarbon contamination on radiocarbon signatures, and to elucidate a possible leakage of chemical warfare agents (CWA) at the Gotland Deep dumpsite. Depleted Delta C-14 values of the TOC (down to -453 parts per thousand) and of the total lipid extracts (down to -812.4 parts per thousand) were detected at the CWA dumpsite. Application of the compound-specific method indicated a possible effect of CWA on depleted Delta C-14 and delta C-13 values in the investigated organic carbon fractions. The obtained results have indicated the different origin and behavior of lipids and TOC at the CWA dumpsite as compared to the area affected by the terrestrial-freshwater OC input. The Delta C-14 data of the TOC and total lipid extracts showed that recent sediments at the CWA dumpsite contain an excess of fossil carbon capable of influencing the C-14 dating at the site.