Archaeal Biomarkers in Antarctica

以前被认为只生活在极端环境中，现在已知的是，海洋中到处都有。这些原核生物可以贡献超过34%的海洋浮游细菌生物量，从而代表了海洋生态系统中生物地球化学循环的重要功能成分。这项探索性研究的小额赠款将调查南大洋中的古细菌和真细菌的相对重要性。将对水柱、沉积物收集器和沉积物芯样进行分析，以确定古菌和细菌的多样性和分布情况。将这两组脂质膜的独特生物标志物的存在与rRNA探针的分子分析结果进行比较。所获得的数据还将用于评价底栖生物中古生物信号的来源。由于古生菌脂质相对耐降解，保存在古代沉积物中可能是预期的，但尚未观察到。相反，这些化合物在沉积物中的浓度表明是原地产生的，而不是从水柱中沉积的。该项目将为评估水柱与沉积古生物标志物之间的关系以及确定底栖生境中古生物的起源提供重要数据。脂质生物标志物分析与分子生态学探测相结合，将为今后南极古生物标志物研究奠定必要的信息基础。

Previously thought to inhabit only extreme environments, Archaea are now known to exist throughout the oceans. These prokaryotes can contribute over 34% of marine bacterioplankton biomass, thereby representing an important functional component of biogeochemical cycling in marine ecosystems. This Small Grant for Exploratory Research will investigate the relative importance of Archaea and Eubacteria in the Southern Ocean. Water column, sediment trap and sediment core samples will be analyzed to quantify archaeal and bacterial diversity and distribution. The presence of unique biomarkers for the lipid membranes of these two groups will be compared to results from molecular analyses with rRNA probes. The data obtained will also be used to evaluate the origin of archaeal signals in the benthos. Since archaeal lipids are relatively resistant to degradation, preservation in ancient sediments might be expected; but has not been observed. Instead, the concentrations of these compounds in sediments suggest in situ production rather than deposition from the water column. This project will provide important data for evaluating the relationship between water column and sedimentary archaeal biomarkers and for determining the origin of archaeal in benthic habitats. The combination of lipid biomarker analysis with molecular ecological probing to test these questions will establish an essential information base for future archaeal biomarker work in Antarctica.