Collaborative Research: A multidimensional approach to understanding microbial carbon cycling beneath the seafloor during cool hydrothermal circulation

合作研究：了解海底冷热液循环期间微生物碳循环的多维方法

• 批准号: 1635365
• 负责人: Peter Girguis
• 金额: $ 35.93万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635365&HistoricalAwards=false
• 关键词: Collaborative; Research; multidimensional; approach; understanding; Collaborative; Research; multidimensional; approach; understanding

The global ocean comprises Earth's largest microbiome, with at least half of the ocean's microbial biomass occurring beneath the ocean floor. In particular, oceanic crust encompasses the largest aquifer on Earth, with a liquid volume equal to approximately 2% of the ocean's volume. It also harbors a substantial reservoir of microbial life that may influence global-scale biogeochemical cycles. This project investigates this largest actively flowing aquifer system on Earth- the fluids circulating through oceanic crust underlying the oceans and sediments. Despite advancing knowledge about life in the deep ocean, the understanding of microorganisms in the rocky oceanic crust and the fluids flowing through it remains rudimentary. This project is focused on understanding the linkages between microbial activity and the cycling of carbon in the cool, subseafloor biosphere. The balance between organic carbon-consuming and organic carbon-producing metabolisms within the crustal biosphere will be determined using seafloor observatories put in place by the International Ocean Discovery Program (IODP) on the flanks of the Mid-Atlantic Ridge, likely representative of the majority of global hydrothermal fluid circulation. The rates of microbial transformations of carbon will be determined using both geochemical and biological approaches. Results will help establish the extent to which microbially-mediated processes in the subseafloor influence carbon cycling in the ocean. This work will represent the first comprehensive description of carbon cycling in the cold oxic crustal aquifer. Two female postdocs will be supported on the grant, and both high school and community college students will also be involved through collaborations with Cape Cod Community College and Cambridge-Rindge and Latin School. The goal is to promote science, technology, engineering and math literacy among high-school and community college students through hand-on research experiences, peer-to-peer mentoring, and professional development opportunities. The goal of the project is to answer the question "is the cool crustal subseafloor biosphere net autotrophic or net heterotrophic?" The focus of the effort is at North Pond, an isolated sediment pond located on ridge flank oceanic crust 7-8 million years old on the western side of the Mid-Atlantic Ridge. The two objectives of the project are to:1. Characterize suspended particles in subseafloor fluids with respect to their inorganic and organic carbon content, and natural 14C and 13C isotopic ratios, to determine microbially-mediated fluxes and processes.2. Characterize the net influence of particle-associated and free-living microbial communities on subseafloor fluid primary production and remineralization, as well as the taxon-specific contributions to these same processes.The integration of isotope geochemical and molecular biological approaches represents a significant cross-disciplinary advance in the understanding of the microbial ecology and geochemistry of the subseafloor biosphere in young oceanic crust and their role in maintaining global deep-sea redox balance. Expected outcomes include identifying signatures of autotrophic and heterotrophic metabolism in particle-associated and free-living subseafloor microbial communities as well as quantification of autotrophic and heterotrophic metabolism and associated taxon-abundances to provide insights into the net and specific microbial processes in crustal fluids on carbon fluxes.

全球海洋包括地球最大的微生物组，其中至少一半的海洋生物量出现在海底下方。特别是，海洋壳包括地球上最大的含水层，其液体体积约为海洋体积的2％。它还拥有大量的微生物寿命储层，可能会影响全球规模的生物地球化学周期。该项目调查了地球上这种主动流动的含水层系统 - 通过海洋和沉积物的海洋壳循环的流体。尽管促进了深海生活的知识，但对岩石海壳中的微生物以及流过它的液体的理解仍然是基本的。该项目的重点是理解微生物活性与碳循环中的碳中膜生物圈中的联系。地壳生物圈内有机碳消费和产生有机碳的代谢之间的平衡将使用国际海洋发现计划（IODP）在中大西洋山脊的侧面实施，这可能是全球水热液循环的主要代表。碳的微生物转化速率将使用地球化学和生物学方法确定。结果将有助于确定子膜中的微生物介导的过程在多大程度上影响海洋中的碳循环。这项工作将代表冷质地壳含水层中碳循环的第一个全面描述。赠款将支持两名女性博士后，高中和社区大学生也将通过与Cape Cod Code Community College和Cambridge-Rindge和Latin School合作参与。目的是通过手工研究经验，点对点指导以及专业发展机会来促进高中和社区大学生中的科学，技术，工程和数学素养。该项目的目的是回答“酷皮地壳子膜生物圈净自养或净异养的问题？”这项工作的重点是北池塘，北池塘是一个孤立的沉积物池塘，位于山脊侧面的海洋壳，在大西洋山脊的西侧有7至800万年的历史。该项目的两个目标是：1。表征悬浮的颗粒相对于其无机和有机碳含量以及天然14C和13C同位素比的悬浮颗粒，以确定微生物介导的通量和过程。2。表征与颗粒相关和自由生活的微生物群落对子液体液的净影响，以及对这些相同过程的分类群特异性贡献，以及分子生物学方法的整合，代表着对小体生态学和地球化的杂志，代表着重要的跨学科进步深海氧化还原平衡。预期的结果包括鉴定粒子相关和自由生活的亚eeploor微生物群落中自养和异养代谢的特征，以及对自养和异养代谢的定量，以及相关的分类群保留率，以在Croustal flelids中为网络和特定的微生物过程提供洞察力。