Distributions of long-chain alkenones and alkyl alkenoates in marine surface sediments from the North East Atlantic

The abundances of long-chain alkenones and alkyl alkenoates are reported for a suite of surface sediments from the NE Atlantic (0°–75°N). Despite the differing conditions of their biologies and differing extents of water column degradation and of early diagenesis in the sediments, the degree of unsaturation of the alkenones (e.g. the U37k parameter), and the relative proportion of alkyl alkenoates to alkenones display linear correlations with average temperature for surface waters warmer than 5°C. There is evidence that the chain-length distribution of the alkenones and of the ratio between the ethyl and methyl C38 alkenones are species dependent, which would enable their use as chemotaxonomic tools.