Fatty acid composition of phytoplankton, settling particulate matter and sediments at a sheltered bivalve aquaculture site

Fatty acid biomarkers were used to investigate the biogeochemistry of a for mer blue mussel (Mytilus edulis) aquaculture site in a shallow. sheltered c ove in northeastern Newfoundland. High levels of polyunsaturated fatty acid s (PUFA) in net-tow and sediment trap samples indicated a substantial phyto plankton source of organic matter, and fluctuations in specific fatty acid biomarkers reflected the changing abundances of diatoms and dinoflagellates . In comparison, sediments contained very low levels of PUFA (< 15%) and we re dominated by terrestrial and bacterial markers. In a separate study, blu e mussels were grown at this closed site, providing the opportunity to exam ine the relationship between lipid supply, as recorded by net-tow and trap samples, and bivalve requirements. The average plankton fatty acid composit ion throughout the year agreed well with that of the adult blue mussels, su ggesting that fatty acids were provided in proportions very similar to the bivalves' requirements. The fatty acid composition of the blue mussels was typical of those collected elsewhere, with PUFA proportions near 50%. Howev er, examination of fatty acid data of plankton sampled in other areas revea led that the plankton in the current study may have been unusual in providi ng fatty acids at levels required by the bivalves. (C) 2001 Elsevier Scienc e B.V. All rights reserved.