Biomarker and Isotope Studies of Organic Matter Cycling in the Black Sea: A Focus on Bacteria and Archaea

该研究由Skidaway的研究人员和Texel （NIOZ -Netherlands）的一个小组合作进行，将对黑海的颗粒有机物（POM）和表层沉积物进行分子生物标志物研究，以描绘古细菌和细菌生物标志物的分布，并推测它们的来源微生物。选择黑海环境是为了提供一个强烈分层，但易于采样的生物反应器系统，该系统具有过去和现在的缺氧海洋盆地的特征。厌氧甲烷氧化是一个全球性的重要过程，但在这样的系统中知之甚少，鉴于最近的建议，古细菌物种可能比以前认为的在氧和真光海洋环境中更常见，因此引起了相当大的兴趣。膜脂来源于二醚类和四醚类的类异戊二烯骨架，是一类多样化的化合物，它们的存在为古细菌中嗜热、嗜冷和其他类群的存在提供了有用的诊断。确定水柱和下垫沉积物中哪些古生物群生活在哪些微生境（缺氧、缺氧、低氧等）区，可能是解释其微生物生态、群落结构和功能的其他天气性评估的重要关键。脂质测量很容易通过现代GC， GC- ms和LC-MS技术进行，可以增强和扩展这些复杂微生物系统的详细和精确的基因组探测。通过对这些分子生物学指标的13C稳定同位素组成的研究，将进一步了解黑海系统中的碳循环和保存。这种测量越来越可能通过化合物特定同位素分析（csia）方法。对黑海有机物循环研究的更广泛影响涉及古细菌原核生物对地球生物地球化学循环的影响的持续定义，它们在消耗沉积和水柱CH4（可能是一种非常重要的温室气体）中的作用，在重建过去气候变化中使用它们的脂质生物标志物，以及进一步说明它们的奇异细胞和酶生物化学的线索。

ABSTRACTOCE-0117824The study, a collaboration between Skidaway researchers and a group at Texel (NIOZ -Netherlands) will carry out molecular biomarker studies of particulate organic matter (POM) and surface sediments of the Black Sea in order to delineate the distributions of archaeal and bacterial biomarkers, and putatively their source microorganisms. The Black Sea environment is chosen to provide a strongly stratified, yet readily sampled, bioreactor system that is characteristic of anoxic marine basins, past and present. Anaerobic methane oxidation, a globally important but poorly understood process in such systems is of considerable interest, given recent suggestions that archael species may be much more common in oxic and euphotic oceanic environments than previously thought. Membrane lipids, derived from the isoprenoid skeletons of di- and tetraethers, are a diverse group of compounds whose presence provides a useful diagnostic for the presence of thermophilic, psychrophilic and other groups amongst the Archaea. The identification of which archael groups inhabit what microhabitat (oxic, anoxic, hypoxic etc) zones within the water column and underlying sediments is likely to be an important key to the interpretation of other synoptic assessments of their microbial ecology, community structure and function. Lipid measurements, readily made by modern GC, GC-MS and LC-MS techniques, may enhance and extend proposed detailed and exacting genomic probing of these complex microbial systems.Additional insight into carbon cycling and preservation in the Black Sea system will be gained from investigation of the 13C stable isotopic composition of these molecular biological indicators. Such measurements are increasingly made possible by compound specific isotopic analysis (csia) methods. Broader impacts into the study of organic matter cycling in the Black Sea relate to continued definition of the impact of archaeal prokaryotes on the earth's biogeochemical cycles, their role in consuming sedimentary and water column CH4 (which may otherwise be a very important greenhouse gas), use of their lipid biomarkers in reconstructing past climate change, and clues to further specification of their exotic cellular and enzymic biochemistries.