Oceanographic control and global distributions of subseafloor microbial life and activity

海底微生物生命和活动的海洋学控制和全球分布

• 批准号: 0752336
• 负责人: Steven D'Hondt
• 金额: $ 81.75万
• 依托单位: University of Rhode Island
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0752336&HistoricalAwards=false
• 关键词: Oceanographic; control; global; distributions; subseafloor

Recent studies of subseafloor life, that is microbes living deep below the ocean?s seafloor, have produced astonishing results that challenge fundamental ideas about the limits and distributions of life. These include; (1) that the microbial biomass of subseafloor sediments is spatially much more variable and possibly much smaller than previously believed; (2) that rates of subseafloor sedimentary microbial activity are far below the rate required for cell maintenance, implying that either most subseafloor cells are inactive or that the energy required for their cellular maintenance is lower than anticipated; and (3) the global distributions of subseafloor sedimentary microbes and their activities are significantly affected by the oceanographic properties of the overlying water column. This proposal will conduct fieldwork to test these ideas at a range of sites in the equatorial Pacific. To do this the principal investigators will conduct a transect study where the following samples and measurements will be taken; (1) coring the sediment to ~18 meter or more below seafloor (mbsf) at 12 sites in the Pacific Ocean, (2) conducting extensive microbiological and biogeochemical analyses of these cores, (3) surveying the oceanographic and geologic characteristics of each site, and (4) using the results to test and refine models for the global distribution of subseafloor microbial abundances and their metabolic activities. With this data the investigators will then address four important questions: What are the principal controls on the magnitude and geographic distribution of subseafloor sedimentary cell abundance and steady-state rates of microbial activities? Can we accurately estimate the magnitude and global distribution of subseafloor sedimentary cell abundance? Can we accurately estimate the global distribution of organic carbon-fueled microbial activity in subseafloor sediment? Do different subseafloor sediments with very different cell abundances and rates of metabolic activity characterized by different groups of organisms? This study will significantly advance our understanding of life in the subseafloor ocean and will provide samples for diverse independent studies, including the International Census of Marine Microbes. This project will also have a strong research and training impact at both the graduate and undergraduate levels as the inherently multidisciplinary nature of subsurface life provides an ideal entry into collaborative modern science. The project will also support a Subsurface Life website at the University of Rhode Island which can be accessed by the public and that will be expanded to include a strong focus on this project and its results. Additional outreach activities include enhancing K-12 education and teacher professional development, in part by integrating a high school science classroom into the at-sea component of the project.

最近对海底生命，也就是生活在海洋深处的微生物--S海底--的研究取得了惊人的结果，挑战了关于生命的极限和分布的基本观点。这些因素包括：(1)海底以下沉积物的微生物生物量在空间上的变异性比以前认为的要大得多，而且可能比以前认为的要小得多；(2)海底以下沉积微生物的活动速度远低于细胞维持所需的速度，这意味着大多数海底以下细胞不是处于不活动状态，就是其维持活动所需的能量低于预期；(3)海底以下沉积微生物的全球分布及其活动严重受到上覆水柱海洋学特性的影响。这项提议将在赤道太平洋的一系列地点进行实地工作，以检验这些想法。为此，首席调查员将进行横断面研究，以便采取下列采样和测量：(1)在太平洋12个地点对海底以下~18米或更深处的沉积物取芯，(2)对这些岩心进行广泛的微生物和生物地球化学分析，(3)调查每个地点的海洋学和地质特征，(4)利用所得结果测试和完善海底微生物丰度及其代谢活动的全球分布模型。有了这些数据，调查人员将解决四个重要问题：控制海底下沉积细胞丰度的大小和地理分布的主要因素是什么，微生物活动的稳态率是什么？我们能否准确估计海底沉积单元丰度的大小和全球分布？我们能否准确估计以有机碳为燃料的海底沉积物中微生物活动的全球分布？不同的海底沉积物具有不同的细胞丰度和代谢活动速率，其特点是不同的生物群吗？这项研究将极大地促进我们对海底生物的了解，并将为包括国际海洋微生物普查在内的各种独立研究提供样本。该项目还将在研究生和本科生层面产生强大的研究和培训影响，因为地下生命固有的多学科性质为合作的现代科学提供了一个理想的入口。该项目还将支持罗德岛大学的一个地下生活网站，该网站可供公众访问，并将得到扩展，以便更多地关注这一项目及其成果。其他外联活动包括加强K-12教育和教师专业发展，部分办法是将高中科学教室纳入该项目的海上部分。