Impact of Photochemistry on Carbon Cycling in the Sea

海水中DOM的ABSTRACTOCE-0096413OCE-0096426Photo-remineralization既可以直接通过溶解的无机碳以二氧化碳和CO的形式产生，也可以通过耦合的光化学和生物途径作用于其他光产物。根据观测到的CO和CO2(DIC)光产生率，PIs目前估计，每天约有0.2-1.5%的DOM(以DOC衡量)可能被直接再矿化，导致DOC在表层海水中的光化学半衰期为46-347天。当考虑光氧化产物底物的光化学增强微生物呼吸时，DOM的半衰期估计进一步减少。本提案将进行的研究旨在更好地限制这些估计，并与初级生产量和微生物活动水平相比较，评估其生物地球化学意义。将进行一系列沿海和开阔海洋环境的研究航行，以更好地估计光化学碳通量。

ABSTRACTOCE-0096413OCE-0096426Photo-remineralization of (DOM) in seawater can occur both directly through the photoproduction of dissolved inorganic carbon (DIC) as CO2 and CO, and secondarily through coupled photochemical and biological pathways acting on other photoproducts. Based on their observed CO and CO2 (DIC) photoproduction rates, the PIs currently estimate that some 0.2-1.5% of DOM (measured as DOC) may be directly remineralized daily, yielding a photochemical half-life for DOC in surface seawater of between 46-347 days. Half-life estimates of DOM are further reduced when photochemically enhanced microbial respiration of photoxidation product substrates is considered. The research to be undertaken in the current proposal is directed at better constraining these estimates and evaluating their biogeochemical significance compared to levels of primary production and microbial activity. Research cruises to a range of coastal and open ocean environments are to be undertaken to better estimate the photochemical carbon flux.