Superoxide radical reactions in the ocean

海洋中的超氧自由基反应

• 批准号: 0551715
• 负责人: Bettina Voelker
• 金额: $ 43.45万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2010-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0551715&HistoricalAwards=false
• 关键词: Superoxide; radical; reactions; ocean

Availability of a newly developed technique for measuring subnanomolar superoxide (O2-) using chemiluminescence detection will allow a researcher at the Colorado School of Mines to conduct superoxide decay experiments at very low micromolar levels, thus allowing, for the first time, accurate measurements of the slower superoxide decay rates expected in open ocean waters and of the rate constants of superoxide reactions with nanomolar concentrations of seawater constituents. Specifically, the scientist will address the following five objectives: (1) carry out direct observations of the kinetics of superoxide decay in unaltered seawater samples; (2) if the lifetime of superoxide is long enough, conduct direct measurement of steady state superoxide concentrations in sunlit seawater; (3) test the hypothesis that superoxide decay proceeds via catalytic redox cycles of seawater constituents; (4) test the hypothesis that the rates of catalytic decay are primarily determined by the water's concentration of weakly complexed copper and chromophoric dissolved organic matter; and (5) measure rate constants important to superoxide decay rates and biogeochemical effects, especially those for iron species. As regards broader impacts, this study will not only improve our ability to predict superoxide in sunlit marine waters, but also allow us to better assess the role of this radical in iron biogeochemistry, as well as in other important marine redox processes. In addition, one post-doc, one graduate student, and one undergraduate student will be supported and trained as part of this project.

使用化学发光检测测量亚纳摩尔超氧化物（O2-）的新开发技术的可用性将使科罗拉多矿业学院的研究人员能够在非常低的微摩尔水平下进行超氧化物衰变实验，从而首次能够准确测量公海水域中预计较慢的超氧化物衰变速率以及与纳摩尔浓度海水的超氧化物反应的速率常数 选民。 具体来说，科学家将实现以下五个目标：（1）直接观察未改变的海水样品中超氧化物衰变的动力学； (2) 如果超氧化物的寿命足够长，则直接测量阳光照射海水中的稳态超氧化物浓度； (3) 检验超氧化物衰变通过海水成分的催化氧化还原循环进行的假设； (4) 检验催化衰变速率主要由水中弱络合铜和发色溶解有机物浓度决定的假设； (5) 测量对超氧化物衰变速率和生物地球化学效应重要的速率常数，尤其是铁物质的速率常数。 就更广泛的影响而言，这项研究不仅将提高我们预测阳光照射海水中超氧化物的能力，而且使我们能够更好地评估这种自由基在铁生物地球化学以及其他重要海洋氧化还原过程中的作用。 此外，作为该项目的一部分，还将支持和培训一名博士后、一名研究生和一名本科生。