Collaborative Research: Microbial Biomarkers at the Chemocline of the Cariaco Basin: Linking Organic Geochemistry and Microbial Ecology

在这个项目中，Skidaway海洋学研究所和宾夕法尼亚州立大学的研究人员将调查委内瑞拉卡里亚科盆地化学渐变区生物标志物分布与微生物过程之间的关系。最重要的假设是，趋化cline中的趋化自养产生了一组具有诊断同位素组成的生物标志物，当这些标志物沉积在下面的沉积物中时，提供了Cariaco盆地水柱趋化自养碳生产和沉积的记录。沉积生物标志物作为水柱微生物过程指示物的准确性取决于将生物标志物与其微生物来源联系起来。该项目有三个具体目标：1)通过在Cariaco盆地的趋化斜区进行紧密采样，获得微生物生物标志物的深度剖面和微生物群落结构，从而评估脂质生物标志物的来源关系。研究人员还将测量沉积物陷阱样本和地表沉积物中的生物标志物，以确定沉积物记录水柱化学自养的程度。2)应用最先进的分析技术进行生物标志物分析，特别是高效液相色谱/电喷雾电离离子阱多级质谱（HPLC/ESI-IT-MSn）分析完整的细菌和古细菌生物标志物。研究人员认为，完整极性脂质（ipl）的生物标志物潜力明显大于传统的基于水解的分析。3)通过将生物标志物与其生物来源及其产生过程联系起来，充分挖掘脂质生物标志物所固有的生物地球化学信息。分子和微生物特征的时空模式将形成理解这些联系的基础，这将通过对脂质和关键碳底物（甲烷，无机碳，如果有的话，醋酸盐）的13C含量的伴随测量得到加强。这个跨学科的项目有许多更广泛的影响。大部分的生物标志物工作将由Skidaway海洋学研究所进行，但该项目是美国、欧洲和委内瑞拉几个实验室的研究人员在不同学科的专业知识之间的合作。在Skidaway，博士后研究员将专注于有机地球化学成分，并将与各种有机地球化学合作伙伴（NIOZ，不来梅）密切合作。委内瑞拉科学家将参加巡游，以提供更多的互动和培训。

In this project, researchers at the Skidaway Institute of Oceanography and the Pennsylvania State University will investigate the relationship between biomarker distributions and microbial processes at the chemocline of the Cariaco Basin, Venezuela. The overriding hypothesis is that chemoautotrophy within the chemocline produces a set of biomarkers with diagnostic isotopic compositions that, when deposited in underlying sediments, provides a record of water column chemoautotrophic carbon production and sedimentation in the Cariaco Basin. The fidelity of sedimentary biomarkers as indicators of water column microbial processes depends upon linking biomarkers with their microbial sources. The project has three specific objectives: 1) To obtain depth profiles of microbial biomarkers and microbial community structure through closely spaced sampling at the chemocline of the Cariaco Basin, and thereby evaluate lipid biomarker-source relationships. The investigators will also measure biomarkers in sediment trap samples and surface sediments to determine how well sediments record water column chemoautotrophy. 2) To apply state-of-the-art analytical techniques for biomarker analyses, notably high performance liquid chromatography/electrospray ionization ion trap multistage mass spectrometry (HPLC/ESI-IT-MSn) to analyze intact bacterial and archaeal biomarkers. The investigators contend that the biomarker potential of intact polar lipids (IPLs) is significantly greater than that obtained by traditional hydrolysis based analyses. 3) To fully exploit the biogeochemical information inherent in lipid biomarkers by linking biomarkers with their biological sources and the processes by which they are produced. Spatial and temporal patterns in molecular and microbial signatures will form the foundation for understanding these linkages, which will be strengthened by companion measurements of the 13C content of lipids and key carbon substrates (methane, inorganic carbon, and if available, acetate). This cross-disciplinary project has a number of broader impacts. Most of the biomarker work will be carried out by Skidaway Institute of Oceanography, but the project is a collaborative effort between investigators having expertise in diverse disciplines and representing several laboratories in the US, Europe, and Venezuela. At Skidaway, a postdoctoral investigator will focus on the organic geochemical component and will work closely with the various organic geochemical partners (NIOZ, Bremen). Venezuelan scientists will participate on cruises in order to provide additional interaction and training.