E 2008, by the American Society of Limnology and Oceanography, Inc. Diel carbon monoxide cycling in the upper Sargasso Sea near Bermuda at the onset of
E 2008, by the American Society of Limnology and Oceanography, Inc. Diel carbon monoxide cycling in the upper Sargasso Sea near Bermuda at the onset of
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DOI：
10.4319/lo.2008.53.2.0835
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发表时间：
2008-03
影响因子：
4.5
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中科院分区：
文献类型：
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一氧化碳（CO）是溶解有机物的光产物，其快速生物氧化会导致昼夜循环，反映光化学-生物地球化学-物理相互作用。这些循环的特点是对水文学、气象学、日照、光学和二氧化碳浓度 ([CO]) 的时间序列研究。尽管强迫不同，但近地表 [CO] 的昼夜模式通常随季节变化很小。夏季，30% 的 CO 位于混合层 (ML) 以下； ML 深度和光学表明双层光化学在其他地方很常见。 [CO] 在两个隔离层中以相似的速率衰减。春季 CO 延伸至 150 m，反映夜间混合。巡航平均剖面表明，由 CO 定义的 ML 比由密度定义的 ML 更浅，说明短命 CO 对近期混合的敏感性。在 ML 以下，[CO] 随深度呈指数下降，其尺度由夏季摄影控制控制，但在春季混合。 CO柱负荷（CB）日变化的质量平衡模型给出了夏季和春季相似的生产率（~50 µmol m−2 d−1 CO），但生物氧化率不同，1.5 ± 0.2 d−1（夏季，0-50 m）和0.52-0.66 d−1（春季，0-200 m）。夏季生物氧化的平均放气量为 4%，春季为 14%。相似的产量和不同的汇导致不同的CB：39.3 µmol m−2（夏季）与94.9 µmol m−2（春季）。日照归一化二氧化碳排放量是贫营养赤道太平洋地区的 1.8 倍。改进的空白分析发现，夏季（通常是春季）200 m 处的 [CO] 始终 <0.1 nmol L−1。由于方法伪影，先前报道的在分层良好的含氧蓝色水域中，[CO] 在深度处系统地≥0.2 nmol L−1 可能很高。
Rapid bio‐oxidation of carbon monoxide (CO), a photoproduct of dissolved organic matter, results in diel cycles reflecting photochemical‐biogeochemical‐physical interactions. These cycles were characterized by time‐series studies of hydrography, meteorology, insolation, optics, and CO concentration ([CO]). Diel patterns of near‐surface [CO] generally varied little seasonally, despite different forcings. In summer 30% of CO was below the mixed layer (ML); ML depths and optics indicate that two‐layer photochemistry is common elsewhere. [CO] decayed at similar rates in both isolated layers. In spring CO extended to 150 m, reflecting nocturnal mixing. Cruise‐average profiles indicated a shallower ML defined by CO than that defined by density, illustrating short‐lived CO’s sensitivity to recent mixing. Below the ML, [CO] dropped exponentially with depth on scales controlled by photoproduction in summer but mixing in spring. Mass‐balance modeling of diurnal variations in CO column burden (CB) gave similar production rates in summer and spring (~50 µmol m−2 d−1 CO), but different biooxidation rates, 1.5 ± 0.2 d−1 (summer, 0‐50 m) and 0.52‐0.66 d−1 (spring, 0‐200 m). Outgassing averaged 4% of bio‐oxidation in summer and 14% in spring. Similar production and differing sinks resulted in different CBs: 39.3 µmol m−2 (summer) versus 94.9 µmol m−2 (spring). Insolation‐normalized CO productions were 1.8 times those in the oligotrophic equatorial Pacific. Improved, well‐blanked analyses found [CO] at 200 m always <0.1 nmol L−1 in summer, and usually in spring. Prior reports of [CO] systematically ≥0.2 nmol L−1 at depth in well‐stratified, oxic blue waters may be high because of method artifacts.