Lipids of aquatic organisms as potential contributors to lacustrine sediments

• Published in: Organic geochemistry Vol. 6; pp. 143 - 152
• Main Authors: Robinson, N., Cranwell, P.A., Finlay, B.J., Eglinton, G.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1984; Elsevier Science
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Geochemistry; Soil and rock geochemistry; Sedimentation rates; Organic matter; Organic materials; Europe; England; United Kingdom; Bacteria; Lipids; Lake sediments
• ISSN: 0146-6380; 1873-5290
• DOI: 10.1016/0146-6380(84)90035-4

The relationship between the lipid composition of organisms in the water column and that of the underlying sediments has been studied in Priest Pot, a eutrophic lake in the English Lake District (area ca 10 4 m 2, depth 3–4 m). Natural populations of rotifers, ciliated protozoa and anoxygenic phototrophic bacteria, present at specific horizons in the water column, were obtained during summer stratification when the hypolimnion was anoxic. The lipids of these organisms have been investigated and compared with those found in the underlying bottom sediments. n-Alkanols within the water column and the bottom sediments showed preferential degradation of shorter chain compounds. An input to the sediment from Chlorobium bacteria was recognized from the presence of farnesol in the sediment. Δ 5,7 Sterols were found to be removed during sedimentation and evidence was obtained for the bacterial hydrogenation of Δ 5 sterols. 4-Methylsterols detected in the lipids of organisms and sediment were attributed to a dinoflagellate origin. Bound sedimentary lipids showed greater preservation of labile compounds compared with the free sedimentary lipids.