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

这项研究是斯基达韦研究人员与特克塞尔(荷兰尼奥兹)的一个研究小组合作的，将对黑海的颗粒有机物(POM)和表层沉积物进行分子生物标记物研究，以描绘古生菌和细菌生物标记物的分布，并推测其来源微生物。选择黑海环境是为了提供一个高度分层但容易取样的生物反应器系统，这是过去和现在缺氧海洋盆地的特征。厌氧甲烷氧化是这类系统中一个全球重要但知之甚少的过程，鉴于最近有迹象表明，古生物物种在氧化和真光海洋环境中可能比之前认为的更常见，因此引起了相当大的兴趣。膜脂来源于二醚和四醚的类异戊二烯骨架，是一类不同的化合物，它们的存在为古生代中是否存在嗜热、嗜冷和其他类群提供了有用的诊断。确定哪些古生物种群栖息在水体和底层沉积物中的微生境(缺氧、缺氧、低氧等)区域，这可能是解释其微生物生态、群落结构和功能的其他天气学评估的重要关键。现代GC、GC-MS和LC-MS技术可以方便地进行脂类测量，这可能会加强和扩大对这些复杂微生物系统的详细和精确的基因组探测。此外，通过研究这些分子生物学指示物的13C稳定同位素组成，将获得对黑海系统碳循环和保存的更多洞察。化合物特定同位素分析(CSIA)方法越来越多地使这种测量成为可能。对黑海有机物质循环研究的更广泛影响涉及继续界定古生物原核生物对地球生物地球化学循环的影响，它们在消耗沉积和水柱CH4(否则可能是一种非常重要的温室气体)方面的作用，利用它们的类脂生物标志物重建过去的气候变化，以及进一步确定它们的外来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.