Lipid geochemistry of methane-seep-related Black Sea carbonates
Lipid geochemistry of methane-seep-related Black Sea carbonates
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DOI：
10.1016/j.palaeo.2005.04.030
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发表时间：
2005-10
期刊：
影响因子：
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通讯作者：
T. Pape;M. Blumenberg;R. Seifert;V. Egorov;S. Gulin;W. Michaelis
中科院分区：
文献类型：
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作者：
T. Pape;M. Blumenberg;R. Seifert;V. Egorov;S. Gulin;W. Michaelis
对从黑海西北部235~1555m深度的缺氧水域中回收的碳酸盐进行了脂肪生物标志物和稳定碳同位素组成的分析。此外，还对甲烷渗漏相关微生物垫和从非渗漏场地回收的表层沉积物样本进行了对比研究。除沉积物外，在所有样品中都发现了高浓度的细菌和古细菌介导的甲烷厌氧氧化(AOM)的强13C耗尽脂类。由特定的脂类模式指示的碳酸盐之间的主要AOM执行群落的差异似乎是由各自的生物地球化学环境引起的。在假定甲烷分压较高的地点发现高比例的ANME-2联合体，而在甲烷供应适中的地点发现ANME-1联合体占主导地位。在沉积结核中，发现了陆生生物和浮游生物的复杂混合生物标志物。不同的分子结构以及稳定的碳同位素组成的强烈变化(δ13C=−20.2‰到−94.3‰)使得可以估计来自浮游的Crenaceota和甲烷营养的Eurya chaeota的四醚结合的双植烷的比例。我们的数据表明，黑海环境中AOM来源的碳酸盐沉淀物的形状受到各自甲烷供应的关键影响。与以前在乌克兰陆架上观察到的类似于以前在乌克兰陆架上观察到的活动的AOM驱动的烟囱状生物礁，也可能在1555米水深的深厚的真信带中发育。
Carbonates recovered from anoxic waters between 235 and 1555 m depth in the northwestern Black Sea were analyzed for lipid biomarkers and stable carbon isotopic compositions. In addition, a methane-seep-related microbial mat and a sample of surface sediment recovered from a non-seep site were studied for comparison. High concentrations of strongly13C-depleted lipids attributed to bacteria and archaea mediating the anaerobic oxidation of methane (AOM) were found in all samples except for the sediment. Differences of the dominant AOM-performing communities between the carbonates indicated by specific lipid patterns appear to be caused by the respective biogeochemical settings. High proportions of ANME-2 consortia are found at sites of assumingly high partial pressures of methane while ANME-1 associations dominate at locations of moderate methane supply. In the sedimentary concretion, a complex mixture of biomarkers for terrestrial and planktonic organisms was found. Different molecular structures along with strong variations in the stable carbon isotopic compositions (δ13C=−20.2‰ to −94.3‰) allow for an estimation of the proportions of tetraether-bound biphytanes derived from planktonic Crenarchaeota and methanotrophic Euryarchaeota. Our data imply that the shape of AOM-derived carbonate precipitates in Black Sea environments is crucially influenced by the respective methane supply. Active AOM-driven chimney-like bioherms, similar to those previously observed on the Ukrainian shelf, might also develop in the deep euxinic zone at 1555 m water depths.