A photochemical model was used to quantify the global contribution of carbonyl photoproduction in the photodegradation of marine dissolved organic carbon (DOC). As model input, wavelength‐ and temperature‐dependent apparent quantum yields (AQYs) for the photochemical production of carbonyl compounds were determined in seawater collected from the Northwest Atlantic Ocean. These AQY data and published AQY data from the North Pacific were used with remotely sensed seawater optical properties and solar irradiance data in a global model to calculate depth‐resolved, mixed‐layer photochemical fluxes of acetaldehyde and glyoxal in seawater. Based on this model, the annual global surface mixed‐layer photochemical production is 89.7 ± 36 Tg year⁻¹ for acetaldehyde and 20.0 ± 8.0 Tg year⁻¹ for glyoxal. This work significantly improves our understanding of the impact of photochemistry on the cycling of DOC in the surface oceans. Low‐molecular‐weight carbonyl compounds represent the second largest carbon flux among all known carbon products that are produced during the photolysis of DOC. The annual photoproduction of carbonyl‐compound carbon is ~110 ± 23 Tg C year⁻¹, comprising approximately 9.6% of the total carbon and 22% of the biologically labile carbon that are produced globally from the photolysis of marine DOC.

中文翻译：

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海水中取决于深度的羰基光化学生产率的全球模型

使用光化学模型来量化羰基光生产在海洋溶解有机碳（DOC）光降解中的总体贡献。作为模型输入，确定了从西北大西洋收集的海水中羰基化合物的光化学生产的波长和温度相关的表观量子产率（AQYs）。这些来自北太平洋的AQY数据和已发布的AQY数据与全球模型中的遥感海水光学特性和太阳辐照度数据一起用于计算海水中乙醛和乙二醛的深度分辨混合层光化学通量。根据该模型，乙醛的全球表面混合层光化学年产量为89.7±36 Tg年^-1，- ^1年为20.0±8.0 Tg年^-1用于乙二醛。这项工作大大提高了我们对光化学对表层海洋DOC循环影响的理解。在DOC光解过程中产生的所有已知碳产物中，低分子量羰基化合物代表第二大碳通量。羰基化合物碳的年光产生量为〜110±23 Tg C year ^-1，约占全球DOC光解产生的总碳的9.6％和生物不稳定碳的22％。