Superoxide radical reactions in the ocean

一种新开发的使用化学发光检测来测量亚纳摩尔超氧化物（O2-）的技术的可用性将允许科罗拉多矿业学院的研究人员在非常低的微摩尔水平下进行超氧化物衰变实验，从而首次允许，准确测量开放海洋沃茨中预期的较慢的超氧化物衰变速率，以及超氧化物与纳摩尔浓度的超氧化物反应的速率常数。海水成分 具体而言，科学家将致力于以下五个目标：（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下海水中稳态超氧化物浓度;（3）测试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）研究海水中超氧化物衰变的动力学。（4）检验催化衰变速率主要由弱络合铜和发色溶解有机物的水浓度决定的假设;（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，特别是铁物种的速率常数。 至于更广泛的影响，这项研究不仅将提高我们的能力，预测阳光照射的海洋沃茨中的超氧化物，但也使我们能够更好地评估这种自由基的作用，铁地球化学，以及在其他重要的海洋氧化还原过程。 此外，一名博士后，一名研究生和一名本科生将作为该项目的一部分得到支持和培训。

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.