Lipids of Recent sediments, Part II. Branched and cyclic alkanes and alkanoic acids of some temperate lacustrine and sub-tropical lagoonal/tidal-flat sediments
| Autor: | P.W. Brooks, D.J. McHugh, Geoffrey Eglinton, R.P. Philip, James R. Maxwell, S.J. Gaskell |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
Pollution
chemistry.chemical_classification biology media_common.quotation_subject Sediment Geology biology.organism_classification Hopanoids Paleontology Hydrocarbon Productivity (ecology) chemistry Algae Geochemistry and Petrology Environmental chemistry Temperate climate Relative species abundance media_common |
| Zdroj: | Chemical Geology. 20:189-204 |
| ISSN: | 0009-2541 |
| DOI: | 10.1016/0009-2541(77)90043-2 |
| Popis: | Analyses of the branched and cyclic alkane and alkanoic acid fractions from three temperate lacustrine and three sub-tropical alagoonal/tidal-flat sediments parallel earlier evidence from the corresponding straight-chain saturated and unsaturated fractions that the soluble organic material originates from both autochthonous and allochthonous sources. Among the lacustrine examples, that are thought to receive the highest contribution from blue-green algae occurs the highest relative abundance of 7- and 8-methylheptadecanes. In contrast, these components were not detected in the bottom sediment of the lake of lowest productivity. Varying concentrations of iso- and anteiso-alkanoic acids were found in the fractions studied in most detail. For example, the low concentrations of these components, obtained by solvent extraction alone of two of the sediments, parallel the distributions of the corresponding n-alkanoic acids in that they do not reflect a high bacterial and/or fungal contribution. The hydrocarbon fractions are, in general, characterised by an envelope of unresolved components and by triterpanes of the hopane type. The unresolved envelope probably originates from pollution of the sediments by fossil fuel products. The distribution of the triterpanes indicates that at least some of these components do not arise from contamination by petroleum products. Triterpenoid acids of the hopane type are present in certain of the sediments, indicating that these geolipids can be formed at the earliest stages of diagnesis. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|