霍帕诺类
沉积物
成岩作用
环境化学
烷烃
水柱
作文(语言)
甾醇
化学
甲藻
地质学
有机化学
碳氢化合物
矿物学
海洋学
古生物学
生物化学
胆固醇
语言学
哲学
构造盆地
烃源岩
作者
P.A. Cranwell,G. Eglinton,Neil Robinson
标识
DOI:10.1016/0146-6380(87)90007-6
摘要
The relationship between the lipid composition of organisms in the water column of an eutrophic lake and the lipid composition of underlying sediments, previously examined for n-alkanols and steroids, is now reported for hydrocarbons, ketones and carboxylic acids. The n-C7 alkane and alkenoic acids from two primary sources are rapidly metabolized in the water column and surficial sediment. Bacterial biomarkers, including hopenes and iai-branched fatty acids, were detected in the photosynthetic bacterial layer occurring just above the sediment-water interface. Within the sediment the apparent conversion of free n-alkanes, alkan-2-ones and ω-hydroxy acids to the corresponding bound form is noted; microbiological oxidation of n-alkanes to alkan-2-ones is supported by the detection of the intermediate alkan-2-ols with a distribution similar to that of the ketones. The geochemistry of sediment deposited c. 1900, prior to biological study of the site, was interpreted from stable biomarkers and the diagenetic changes recognised in the study of contemporary deposition. A qualitative difference in algal input to the older sediment is inferred from the low Δ7-sterol content and presence of 2,6,10-trimethyl-7-(3-methylbutyl)-dodecane. However, there was still significant dinoflagellate input, as indicated by the presence of 4α-methylsterols. A difference in higher-plant input to the older sediment, indicated from the n-alkane, alkene and triterpenoid ketone distributions, is consistent with the recent development of tree cover.
科研通智能强力驱动
Strongly Powered by AbleSci AI