Oxidation-Reduction Photochemistry in Marine Systems.
WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
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The principal net process in natural water photochemistry is light-catalyzed oxidation of a various organic compounds Dissolved Organic Carbon, DOC, with concurrent reduction of dissolved oxygen DOC 02 light right arrow oxidized DOC e.g. CO, CO2, carbonyl compounds HOOH. We explored the hypothesis that HOOH forms by one electron reduction of oxygen to superoxide O2- which then dismutates to HOOR. We also quantified 02- fluxes and defined some HOOH reaction paths. 1 02- fluxes were quantified in two seasons in the eastern Caribbean they correlated with total free radical fluxes and with runoff of the Orinoco and Amazon Rivers. 2 Isotopic methods were applied to characterize the slower chemical and biological decay of HOOH. 3 Pulse radiolysis fast-kinetics studies in seawater medium elucidated in detail the kinetics and nature of the dismutation proton and Cu catalysis that forms HOOH. 4 A method for directly measuring the steady-state in situ concentration not flux of O2-in sunlit surface waters was developed and deployed at sea on the RV Columbus Iselin, which went hard aground on day 3 ONR declined to continue support. 5 A quantitative timeseries model of CO photochemistry was developed.
- Organic Chemistry
- Biological Oceanography