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

为了应对全球气候变化，贫氧水柱（ODWC）似乎正在扩大。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。缺氧的强度和持续时间各不相同，从季节性缺氧到永久性缺氧。本研究的重点是缺氧端元的典型例子——卡里亚科盆地。总体目标是研究微生物功能潜力（宏基因组）、活性（宏转录组）、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）与垂直氧/地球化学梯度以及卡里亚科盆地季节之间的关系。这将揭示特定基因组的表达、营养物质、能量底物和氧化剂可用性的环境差异之间的关系。目标是：（1）将水文学、地球化学和微生物生态数据与宏基因组和宏转录组图谱相结合，以了解定义微生物群落在高生产力和低生产力时期对环境强迫的反应的调控和代谢网络。这将有助于了解甲烷厌氧氧化、氧化还原敏感金属的利用、ODWC 中神秘的硫循环以及缺氧对氮转化的影响等过程的重要性。 (2) 确定本 ODWC 中微生物真核生物 (mEuks) 和原核生物之间关联的重要性。 (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，作为进一步生化表征和分子探针开发的目标，并使用 qPCR 跨氧化还原梯度对这些基因和转录物的关键子集进行量化。 （4）为开发利用指示重要元素转化和通量的表达基因的监测工具提供基础，以诊断自然和人类工程生态系统的健康状况。 (5) 将结果与其他 ODWC 最近和正在进行的研究进行比较，以辨别这些系统的共享和独特属性。智力优点：ODWC 的先前研究强调需要更多有关 ODWC 中微生物群落结构和功能的数据，特别是生化速率测量和有关群落对变化条件的反应的其他数据。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的更好的预测模型对于为未来的政策和管理决策提供信息至关重要。迫切需要来自卡里亚科盆地等缺氧端元 ODWC 的数据与其他近期和正在进行的季节性枯竭沿海系统、永久枯竭深盆地和西部边界氧气最低区 (OMZ) 研究的数据进行比较，以构建更熟练的模型。这项研究将增进对世界各地扩大 ODWC 影响的理解，超越仅基于分类多样性的评估，从而对这些环境中主要微生物群的生态学和生理学以及细菌、古细菌和微生物真核生物之间的相互作用产生新的见解。 更广泛的影响：PI 及其合作者将培训一名研究助理、一名博士后研究员、一名研究生和 SBU 的众多本科生。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（例如显微镜）和“尖端”（例如宏基因组学/转录组学）技术。 PI 还将涉及 Zephyr 教育基金会位于马萨诸塞州伍兹霍尔的海洋科学素养和教育项目。 PI 将与该组织合作，利用 Zephyr 组织的当地乘船实地考察以及由 PI 设计的讲座和课堂实验室练习来教育市中心的 K-12 学生。此外，该项目将对理解 ODWC 如何影响海洋生态系统产生广泛影响，并可能影响未来描述海洋和大气之间碳和氮循环的管理策略和模型。

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.