Organic geochemistry on surface sediments from the Laptev Sea

DOI

Sediment samples from the Laptev Sea, taken during the 1993 RV Polarstern expedition ARK IX/4 and the RV Ivan Kireyev expedition TRANSDRIFT I, were investigated for the amount and composition of their organic carbon fractions. Of major interest was the identification of different processes controlling organic carbon deposition (i.e. terrigenous supply vs. surface water productivity). Long-chain unsaturated alkenones derived from prymnesiophytes, and fatty acids derived from diatoms and dinoflagellates, were analysed by means of gas chromatography and mass spectrometry. First results on the distribution of these biomarkers in surface sediments indicate that the surface water productivity signal is well preserved in the sediment data. This is shown by the distribution of the 16:1(n-7) and 20:5(n-3) fatty acids indicative for diatoms, and the excellent correlation with the chlorophyll a concentrations in the surface water masses and the biogenic-opal content and increased hydrogen indices of the sediments. The high concentration of these unsaturated fatty acids in shallow water sediments shows the recent deposition of the organic material. In deep-sea sediments, on the other hand, the concentrations are low. This decreased content is typical for phytoplankton material which has been degraded by microorganisms or autoxidation. In general, the alkenone concentrations are very low, suggesting low production rates by prymnesiophytes. Only at one station from the lower continental margin influenced by the inflow of Atlantic water masses, were some higher amounts of alkenones determined. Long-chain n-alkanes as well as high C/N ratios and low hydrogen indices indicate the importance of (fluvial) supply of terrigenous organic matter.

Supplement to: Fahl, Kirsten; Stein, Ruediger (1997): Modern organic carbon deposition in the Laptev Sea and the adjacent continental slope: surface water productivity vs. terrigenous input. Organic Geochemistry, 26(5-6), 379-390

Identifier
DOI https://doi.org/10.1594/PANGAEA.54605
Related Identifier https://doi.org/10.1016/S0146-6380(97)00007-7
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.54605
Provenance
Creator Fahl, Kirsten ORCID logo; Stein, Ruediger ORCID logo
Publisher PANGAEA
Publication Year 1997
Funding Reference Fourth Framework Programme https://doi.org/10.13039/100011105 Crossref Funder ID MAS3980185 https://cordis.europa.eu/project/id/MAS3980185 Quaternary Environment of the Eurasian North
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 260 data points
Discipline Earth System Research
Spatial Coverage (101.592W, 71.690S, 139.670E, 79.652N); Laptev Sea; Vilkitsky Strait; Laptev Sea, Taymyr Island
Temporal Coverage Begin 1993-08-11T00:00:00Z
Temporal Coverage End 1993-09-23T00:00:00Z