Microbial Activities in Deep-Subsurface Sediments Beneath Mid-Ocean Gyres

大洋中环流下深层地下沉积物中的微生物活动

• 批准号: 1131671
• 负责人: Wiebke Ziebis
• 金额: $ 28.78万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1131671&HistoricalAwards=false
• 关键词: Microbial; Activities; Deep; Subsurface; Sediments

The nature of subsurface life is very poorly known. Ocean gyres are the major oceanographic provinces on our planet but the seafloor underlying these oligotrophic open ocean regions is the least explored. Most sub-seafloor investigations have focused on high productivity regions near continental margins. This project proposes to use innovative and experimental stable and radio - isotopiv approaches to address the metabolic activity and the biogeochemical cycling of key compounds (C, N, O) in oligotrophic sub-seafloor sediments underlying the oligotrophic South Pacific Gyre and South Atlantic Gyre.Intellectual Merit: The primary objectives of this proposal are to determine metabolic activities (aerobic respiration, heterotrophy/autotrophy) and to track potential routes of C, N and P fixation and turnover using sensitive stable and radioisotope methods, cell extractions and single cell analyses including nano-scale secondary mass spectrometry (nanoSIMS). The fundamental goals are to document geographic variation in subsurface habitat conditions and microbial metabolic activities and to test the factors controlling those activities. The proposed study will test for and quantify heterotrophic and autotrophic metabolisms in a comparison of (a) ocean regions (gyre center to gyre margin in both the Atlantic and Pacific), b) sediment depth and c) relation to processes in the underlying basalt. This research will addresses key questions in sub-seafloor investigations: What are the principal microbial activities in open ocean sub-seafloor sediments? What are the principal sources of metabolic energy? What are the rates of these activities? The results of the proposed investigations will be transformative to the fields of deep-biosphere microbial ecology and biogeochemistry, as they will significantly advance our understanding of the subsurface biome that may be representative for major areas of the ocean floor. Broader Impacts: One postdoctoral fellow will take part in this project and will receive training in research, mentoring, and career preparation. This project will engage undergraduate students who will participate in the research. The proposed research is directly in support and advances large investments made for IODP expeditions 329 (South Pacific Gyre) and 336 (South Atlantic Gyre), which have a unique focus on subsurface microbiology. This project will strengthen international collaborations between IODP scientists and includes close collaborations with the MPI in Bremen, Germany. The NSF Center for Dark Energy Biosphere Investigations at USC (C-DEBI) provides educational opportunities for teachers, K-12 students, undergraduate and graduate students, as well as post-doctoral researchers to train with the aim to foster the next generation of deep subseafloor biosphere researchers, as well as to translate knowledge in the field of deep biosphere research to the broader public.

我们对地下生命的性质知之甚少。海洋环流是我们这个星球上主要的海洋学领域，但这些营养不良的开放海洋地区的海底是最少被探索的。大多数海底调查都集中在靠近大陆边缘的高生产力区域。本项目建议采用创新的、实验性的稳定同位素和放射性同位素方法来研究南太平洋环流和南大西洋环流下少营养海底沉积物中关键化合物（C、N、O）的代谢活性和生物地球化学循环。智力优势：本提案的主要目标是确定代谢活动（有氧呼吸，异养/自养），并利用敏感的稳定和放射性同位素方法，细胞提取和单细胞分析（包括纳米级二级质谱分析（nanoSIMS））跟踪C， N和P固定和转换的潜在途径。基本目标是记录地下生境条件和微生物代谢活动的地理变化，并测试控制这些活动的因素。拟议的研究将通过比较（a)海洋区域（大西洋和太平洋的环流中心到环流边缘），b）沉积物深度和c)与下伏玄武岩过程的关系来测试和量化异养和自养代谢。这项研究将解决海底调查中的关键问题：开放海洋海底沉积物中的主要微生物活动是什么？代谢能量的主要来源是什么？这些活动的比率是多少？拟议的调查结果将对深海生物圈微生物生态学和生物地球化学领域产生革命性的影响，因为它们将大大促进我们对海底主要地区的地下生物群系的理解。更广泛的影响：一名博士后将参与该项目，并将接受研究，指导和职业准备方面的培训。本项目将招收本科生参与研究。拟议的研究直接支持和推进了IODP远征329（南太平洋环流）和336（南大西洋环流）的大笔投资，这两个项目对地下微生物学有独特的关注。该项目将加强IODP科学家之间的国际合作，包括与德国不来梅MPI的密切合作。美国国家科学基金会暗能量生物圈研究中心（C-DEBI）为教师，K-12学生，本科生和研究生以及博士后研究人员提供教育机会，旨在培养下一代深海底生物圈研究人员，并将深生物圈研究领域的知识转化为更广泛的公众。