Collaborative Research: Genetic and Metabolic Signatures of Marine Microorganisms in Oxygen Depleted and Varying Geochemical Seascapes (MetaOmics in the Cariaco Basin)

耗氧水柱(ODWCs)似乎正在扩大，以应对全球气候变化。这改变了营养结构，压缩了栖息地，并改变了主要元素的地球化学循环。从季节性缺氧到永久性缺氧，缺氧的强度和持续时间各不相同。这项研究的重点是一个典型的缺氧终端成员，卡里亚科盆地。总体目标是研究微生物功能潜力(元基因组学)、活动(元基因组学)、分类多样性(基于SSU rRNA)和生态/地球化学后果(根据关键过程的测量速率)在垂直氧气/地球化学梯度上以及在Cariaco盆地不同季节之间的关系。这将揭示特定基因组的表达、营养物质的环境差异、能量底物和氧化剂可获得性之间的关系。目标是：(1)将水文、地球化学和微生物生态数据与元基因组和元转录图谱相结合，以了解调控和代谢网络，定义微生物群落对高和低生产力时期环境胁迫的反应。这将有助于理解过程的重要性，如甲烷的厌氧氧化，对氧化还原敏感的金属的利用，这一ODWC中隐蔽的硫循环，以及氧气耗尽对氮转化的影响。(2)确定微生物真核生物(MEuk)和原核生物之间的联系在本ODWC中的重要性。(3)识别可能与主要元素和微量气体循环相关的已知或未知功能的“指示”基因，作为进一步生化特征和分子探针开发的靶标，并使用qPCR定量这些基因的关键子集和跨氧化还原梯度的转录本。(4)为利用指示重要元素变化的表达基因和通量开发监测工具提供基础，以诊断自然和人类工程生态系统的健康状况。(5)与最近和正在进行的其他ODWCs的研究结果进行比较，以找出这些系统的共同和独特的属性。智力上的优点：以前对ODWCs的研究强调需要更多关于ODWCs中微生物群落结构和功能的数据，特别是生化速率测量和关于群落对不断变化的条件的反应的其他数据。更好地预测海洋微生物群落和生物地球化学过程对全球气候变化的反应，对于为未来的政策和管理决策提供信息至关重要。迫切需要来自像Cariaco盆地这样的缺氧末端成员的数据，以与最近和正在进行的其他季节性枯竭沿海系统和永久枯竭的深盆地和西部边界最低含氧区(OMZ)的研究数据进行比较，以构建更熟练的模型。这项研究将促进对世界各地扩大ODWCs的影响的理解，超越仅基于分类多样性的评估，对这些环境中主要微生物类群的生态和生理以及细菌、古生物和微生物真核生物之间的相互作用产生新的见解。广泛的影响：PIs及其合作者将从SBU培训一名研究助理、一名博士后研究员、一名研究生和许多本科生。所有人员都将接受微生物生态学和海洋学各个方面的培训，重点是传统技术(如显微镜)和“前沿”技术(如元基因组学/转录组学)。PI还将涉及位于马萨诸塞州伍兹霍尔的泽菲尔教育基金会的海洋科学素养和教育计划。PIS将与该组织合作，利用Zephr组织的当地游船实地考察以及由PIS设计的讲座和课堂实验室练习来教育市中心K-12学生。此外，该项目将对了解有机污染物如何影响海洋生态系统产生广泛影响，并可能影响描述海洋和大气之间碳和氮循环的未来管理战略和模型。

Oxygen depleted water columns (ODWCs) appear to be expanding in response to global climate change. This alters trophic structure, compresses habitat and modifies geochemical cycles of major elements. Oxygen depletion can vary in intensity and duration from seasonal hypoxia to permanent anoxia. The focus of this study is a classic example of the anoxic end-member, the Cariaco Basin. The overall goal is to examine how microbial functional potential (metagenomic), activity (metatranscriptomic), taxonomic diversity (based on SSU rRNA) and the ecological/geochemical consequences (in terms of measured rates of key processes) relate along vertical oxygen/geochemical gradients and between seasons in the Cariaco Basin. This will reveal relationships between expression of particular sets of genes, environmental differences in nutrients, energy substrates and oxidant availabilities.The objectives are to: (1) Integrate hydrographic, geochemical and microbial ecological data with metagenomic and metatranscriptomic profiles to understand regulatory and metabolic networks defining microbial community responses to environmental forcing during high and low productivity periods. This will help to understand the importance of processes, such as anaerobic oxidation of methane, utilization of redox-sensitive metals, the cryptic sulfur cycle in this ODWC, and the impacts of oxygen depletion on nitrogen transformations. (2) Determine the importance of associations between microbial eukaryotes (mEuks) and prokaryotes in this ODWC. (3) Identify "indicator" genes of known or unknown function that may be relevant to major elemental and trace gas cycling as targets for further biochemical characterization and molecular probe development, and quantify a key subset of these genes and transcripts across redox gradients using qPCR. (4) Provide a basis for developing monitoring tools using expressed genes indicative of important elemental transformations and fluxes for diagnosing the health status of natural and human engineered ecosystems. (5) Compare results with recent and ongoing studies of other ODWCs to discern shared and unique attributes of these systems.Intellectual Merit: Previous studies of ODWCs have underscored the need for more data on microbial community structure and functionality in ODWCs, particularly biochemical rate measurements and other data on community responses to changing conditions. Better predictive models of responses of marine microbial communities and biogeochemical processes to global climate change are essential for informing future policy and management decisions. Data from an anoxic end-member ODWC like Cariaco Basin are critically needed to compare with data from other recent and ongoing studies of seasonally-depleted coastal systems and permanently-depleted deep basin and western boundary oxygen minimum zones (OMZs) to construct more skillful models. This study will advance the understanding of impacts of expanding ODWCs around the world, moving beyond assessments based only on taxonomic diversity, to yield new insights into the ecology and physiology of major microbial groups in these environments and interactions among Bacteria, Archaea and microbial eukaryotes.Broader Impacts: The PIs and their collaborators will train one Research Associate, one postdoctoral investigator, a graduate student, and numerous undergraduates from SBU. All personnel will be trained in various aspects of microbial ecology and oceanography, with an emphasis on both traditional (e.g., microscopy) and "cutting edge" (e.g. metagenomics/transcriptomics) techniques. The PIs will also involve the Zephyr Education Foundation's marine science literacy and education program, located in Woods Hole, MA. The PIs will work with this organization to educate inner city K-12 students using local boat field trips organized by Zephyr, and lectures, and classroom laboratory exercises designed by the PIs. Additionally, this project will have broad implications for understanding how ODWCs affect marine ecosystems, and may influence future management strategies and models describing the cycling of C and N between the ocean and atmosphere.