Hydrogen production and nitrogen fixation in the North Pacific Subtropical Gyre

北太平洋副热带环流的氢气生产和固氮

• 批准号: 1153656
• 负责人: David Karl
• 金额: $ 28.14万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1153656&HistoricalAwards=false
• 关键词: Hydrogen; production; nitrogen; fixation; North

In this project, researchers at the University of Hawaii a Manoa will conduct a series of field and laboratory studies to develop a quantitative understanding of dissolved hydrogen (H2) cycling in the oligotrophic North Pacific Ocean. Dissolved H2 concentrations in the surface ocean typically range from 1-3 nM which represents 300-900% supersaturation relative to atmospheric concentrations. This persistent supersaturation of dissolved H2 in the surface waters of subtropical and tropical oceans makes the oceans a source of atmospheric H2 and compiled budgets of global H2 sources estimate marine emissions from 3 to 6 Tg H2 yr-1. The broad objectives of the research are: (1) to quantify the linkages and stoichiometry between H2 production and N2 fixation in surface seawater of the open ocean, and (2) to determine the factors that drive this relationship including the microbial community composition and the influence of light intensity. The field research will be conducted over a two-year period at Station ALOHA and will complement the ongoing Hawaii Ocean Time-series (HOT) program. Broader Impacts: Quantifying the H2 cycling in surface waters of the upper water column will constrain existing estimates of global marine H2 emissions. Furthermore, an improved understanding of H2 cycling will help predict potential effects of increasing anthropogenic emissions of H2 increase or a climate-driven change in the community structure of marine diazotrophs. These results will be valuable to microbial ecologists, biogeochemists, and climate change scientists. All resulting oceanographic and laboratory datasets will be archived in the online HOT and Center for Microbial Oceanography: Research and Education (C-MORE) data centers and made publicly available. At least one undergraduate student will be hosted through the C-MORE scholars program which particularly targets Native Hawaiians and Pacific Islanders majoring in an ocean or earth science-related field.

在这个项目中，夏威夷大学马诺阿分校的研究人员将进行一系列实地和实验室研究，以定量了解北太平洋少营养化海洋中的溶解氢(H2)循环。表层海洋中溶解的氢气浓度通常在1-3海里之间，相对于大气浓度，这代表了300-900%的过饱和度。亚热带和热带海洋表层水中溶解的氢气的这种持续过饱和使海洋成为大气氢气的来源，编制的全球氢气源预算估计海洋排放量为3-6TgH2 yr-1。这项研究的主要目标是：(1)量化公海表层海水中氢的产生和固定与氮固定之间的联系和化学计量，(2)确定驱动这种关系的因素，包括微生物群落组成和光照强度的影响。实地研究将在Aloha站进行为期两年的时间，并将补充正在进行的夏威夷海洋时间序列(HOT)计划。更广泛的影响：量化上层水柱表层水中的氢循环将限制对全球海洋氢排放的现有估计。此外，对氢气循环的更好理解将有助于预测人为增加的氢气排放量增加的潜在影响，或者气候驱动的海洋重氮菌群落结构的变化。这些结果将对微生物生态学家、生物地球化学家和气候变化科学家有价值。所有由此产生的海洋学和实验室数据集将在微生物海洋学研究和教育中心(C-MORE)的在线热点和中心数据中心存档，并公开提供。至少有一名本科生将通过C-More学者计划获得接待，该计划特别针对主修海洋或地球科学领域的夏威夷原住民和太平洋岛民。