Impact of Photochemistry on Carbon Cycling in the Sea

海水中DOM的光致分解可以直接通过溶解无机碳（DIC）的光生成（如CO2和CO）来进行，也可以通过作用于其他光产物的耦合光化学和生物途径来进行。根据他们观察到的CO和CO2（DIC）光生速率，PI目前估计，每天约有0.2-1.5%的DOM（以DOC计）可能被直接矿化，从而得出表层海水中DOC的光化学半衰期为46-347天。当考虑光氧化产物基质的光化学增强微生物呼吸作用时，DOM的半衰期估计值进一步降低。本提案中拟开展的研究旨在更好地限制这些估计数，并评价其相对于初级生产和微生物活动水平的生物地球化学意义。将对一系列沿海和公海环境进行研究航行，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.