Collborative Research: Laboratory Investigation of Redox Reactions during Subsurface Mixing in Submarine Hydrothermal Systems

合作研究：海底热液系统地下混合过程中氧化还原反应的实验室研究

• 批准号: 1558750
• 负责人: Jeffrey Seewald
• 金额: $ 37.78万
• 依托单位: Woods Hole Oceanographic Institution
• 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: 2016-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1558750&HistoricalAwards=false
• 关键词: Collborative; Research; Laboratory; Investigation; Redox

Submarine hot-springs at oceanic spreading centers form in response to heat associated with volcanic activity responsible for the creation of new oceanic crust. This heating of seawater to temperatures as high as 400°C, as it circulates through the ocean crust, results in extensive chemical reactions that modify the fluid's composition to something that is acidic, metal- and sulfide-rich, and highly reducing. Venting of these fluids at the seafloor and mixing with seawater creates a chemical environment that supports large microbial ecosystems that do not rely on the sun (photosynthesis) as a source of energy. Instead, they are sustained by catalyzing chemical reactions that occur when hot and reduced hydrothermal fluids mix with cold oxidized seawater. The ability of microbes to utilize these reactions as an energy source is highly dependent on the abundance and composition of chemical compounds that participate in these types of oxidation-reduction reactions. This research conducts laboratory experiments to determine the rate of abiotic (i.e., not involving life) chemical reactions that produce or consume chemical compounds used by deep sea microbes. These data improve our understanding of how subsurface microbes and the higher order marine ecosystems, that rely on these microbes as the base of the food web, thrive on the bottom of the seafloor thousands of feet below the sea surface. Broader impacts of the work include a substantial educational component that provides state-of-the-art research experiences for 25 undergraduate science majors at a primarily undergraduate institution (Bridgewater State University) through partnership with a major oceanographic research institution (the Woods Hole Oceanographic Institution). This integration of research and education includes the development and implementation of a research course, offered at Bridgewater State, and intensive summer research experiences at Woods Hole. The goal is to provide undergraduates with opportunities to experience all aspects of the scientific process, including background research, data collection, analysis and interpretation, and presentation of results at a national conference in order to better prepare them for employment and graduate study.This research consists of laboratory experiments that investigate abiotic redox reactions in subsurface mixing zones in seafloor hydrothermal systems. Using a novel laboratory reactor, experiments investigate chemical disequilibria between key redox reactive species in seawater (e.g., H2, H2S, Fe2+, CH4, O2, SO42-, CO2, NO3-), which comprise a major source of chemical energy that supports complex subsurface ecosystems. At present, such reactions are poorly constrained in hydrothermal environments, so this work identifies these reactions and determines their rates at low to moderate temperatures that characterize subsurface mixing zones within hydrothermal systems. The resulting data will allow improvement of models of hydrothermal vent microbial metabolic pathways. Experiments will take place using an open-system flow-through reaction cell that is able to regulate the concentration of H2, O2, H2S, NO3-, and intermediate oxidation state sulfur and nitrogen species as a function of temperature and pH. Data will be used to place fundamental constraints on thermodynamic models used to predict the amount of chemical energy delivered to vent ecosystems, which should lead to an improved understanding of the linkages between chemical environment and biological community composition and function.

海洋传播中心的海底热弹力与火山活动相关的热量，创造了新的新的新的新的新的新的新纽维克锈病。海壳会导致广泛的化学反应对酸性，金属和硫化物富含硫化物的液体的液体在海底的含量。作为一种能量，它们是通过催化化学的速度，并降低了水热层与氧化的海水混合在一起。 （即，不是涉及的寿命）产生或消耗iCrobes使用的化学可笑化合物这通过与主要的海洋学研究所的合作伙伴关系为25个本科研究所的本科科学提供了最先进的研究经验。夏季重新体验伍兹孔。在地下实验室反应器中实验的实验反应，实验研究了化学不平衡海水中的不平衡反应（例如，H2，H2S，FE2+，O2，O2，SO42-，NO3-，NO3-）SE的主要化学能源来源，这些化学能源的主要来源是在目前的复杂地下生态系统。这种反应是在水热系统中表征地下混合区的不良反应。 O2，H2S，NO3- ULFUR和氮种类为女性和pH，将基本的限制用于用于用于通风生态系统的化学能量的热力学模型化学环境和生物学社区的综合组成和功能。