Molecular Distributions and D/H Ratios of Marine Archaea Lipids: Evaluating their Potential as Paleosalinity Proxies

深海古菌是海洋浮游微生物群的重要组成部分，广古菌和泉古菌在世界海洋中分布广泛，数量丰富。这些生物的细胞膜由醚连接的类异戊二烯脂质组成，这些脂质相对来说是不饱和的，因此在沉积记录中保存良好。最近对这些化合物的调查显示，它们的结构和相对丰度记录了重要的环境信息，包括地表水温度。脂质膜包括细胞生命和其物理环境之间的界面，并且其他环境特性，特别是盐度，可能与膜结构特性的变化有关。此外，这些结构是潜在的有用的记录水在其生长环境中的氢同位素组成，提供了一个独立的测量salinity.On这个项目，研究人员在宾夕法尼亚州州立大学将评估H同位素分馏之间的沃茨和脂质，以及脂质结构和它们的分布，以确定这些属性之间的关系和生长环境中的沃茨。 他们将调查从海洋和沿海沃茨多个深度和时间收集的悬浮颗粒物中提取的脂质。 他们将从钦科蒂格湾收集样本，钦科蒂格湾是一个相对原始的河口，其沃茨在空间和季节上从淡水到海水不等，他们还将使用在预定的黑海、地中海和百慕大附近沃茨航行期间收集的样本。他们之前曾从西西里海岸的一个盐制造基地的高盐盆地收集样本并存档。 所研究的样品范围从新鲜到高盐条件。除了实地研究之外，还将利用选定的在一定温度和盐度范围内生长的、同位素限制的基质进行对照实验。这种双重属性的方法的效用将通过分析与晚中新世的墨西拿盐度危机ODP样品中的脂质进行评估。将开发一个支持MS论文项目，使用过去8,000年的沉积物记录调查与黑海海洋入侵事件相关的脂质记录

ABSTRACTOCE-0327347The Archaea constitute a significant portion of pelagic marine microbiota, with members of the Euryarchaeota and Crenarchaeota abundant and widespread in the world's oceans. The membranes of these organisms are composed of ether-linked isoprenoid lipids, which are relatively recalcitrant and therefore well preserved in sedimentary records. Recent investigations of these compounds reveal important environmental information is recorded by their structures and their relative abundances, including surface-water temperatures. Lipid membranes comprise the interface between cellular life and its physical environment, and it is likely that other environmental properties, especially salinity, are associated with changes in the properties of membrane structures. Further, these structures are potentially useful recorders of the hydrogen isotopic composition of water in their growth environment, providing an independent measure of salinity.On this project, researchers at the Pennsylvania State University will evaluate H isotopic fractionation between waters and lipids, as well as lipid structures and their distributions in order to determine relationships between these properties and those of waters in the growth environment. They will survey lipids extracted from suspended particulate matter collected at multiple depths and times from oceanic and coastal waters. They will collect samples from the Chincoteague Bay, a relatively pristine estuary, with waters that range spatially and seasonally from fresh to marine and will also employ samples collected during scheduled cruises to the Black Sea, the Mediterranean and to waters near Bermuda. They have previously collected and archived samples from hypersaline basins in a salt-manufacturing site on the coast of Sicily. The samples studied will range from fresh to hypersaline conditions. Field studies will be complemented by controlled experiments using selected Archaea taxa, grown under a range of temperatures and salinities and using isotopically constrained substrates. The utility of this dual-property approach will be evaluated by analysis of lipids in ODP samples associated with the late-Miocene Messinian Salinity Crisis. A supporting MS thesis project will be developed to investigate the lipid record associated with the marine incursion event in the Black Sea using sediment records from the past 8,000 years