Biogeochemistry of fatty acids in recent sediments from Narragansett Bay,Rhode Island

The fatty acid composition of sediments from Narragansett Bay show significant variation between certain areas of the Bay. Both the organic carbon and fatty acid concentrations decrease with increasing distance from the Providence River area—an area which received municipal sewage and industrial effluents. The ratio of the fatty acid concentration to organic carbon concentration is fairly constant for all stations sampled. The variations in the relative abundance of fatty acids may reflect either the influence of fatty acids discharged to the river area by sewage effluents or the synthesis of fatty acids by microbial populations which probably differ for the areas compared. Temporal variations in fatty acid composition and fatty acid concentration are minimal. Lipolytic activity has been demonstrated and probably acts on glycerides deposited to the sediments releasing free fatty acids shortly after deposition. A model for the diagenesis of fatty acids in Recent sediments is proposed based upon the above findings and upon earlier reports by the authors and by other investigators.