Photobiogeochemical cycling of carbon monoxide in the southeastern Beaufort Sea in spring and autumn
Photobiogeochemical cycling of carbon monoxide in the southeastern Beaufort Sea in spring and autumn
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DOI：
10.4319/lo.2009.54.1.0234
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发表时间：
2009-01
影响因子：
4.5
通讯作者：
Huixiang Xie;S. Bélanger;S. Demers;W. Vincent;T. Papakyriakou
中科院分区：
文献类型：
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作者：
Huixiang Xie;S. Bélanger;S. Demers;W. Vincent;T. Papakyriakou
我们调查了2003年秋季和2004年春季博福特海东南部开放沃茨中一氧化碳（CO）的分布、光生、微生物吸收和海气交换，CO是发色溶解有机物（CDOM）的关键光产物。地表水CO浓度（[CO]）的日变化主要发生在秋季，而春季没有。在这两个季节中，大多数站点的[CO]都远高于空气平衡（最大饱和度为12，500%），并随深度下降至50 m以下无法检测的水平。平均地表水[CO]和CO水柱负荷（0 - 50 m）在秋季为0.45 nmol L−1和5.0 µmol m−2，春季为4.7 nmol L−1和64.8 µmol m−2，春季海-气CO通量高33倍。CO光生效率与CDOM线性相关的麦肯齐河口，麦肯齐货架，和阿蒙森湾。春季模拟的水柱CO光生是秋季的15倍（45.8 vs. 3.0 µmol m−2 d−1）。秋季微生物CO吸收遵循一级动力学，而春季表层沃茨中常见Hill型、饱和和抑制动力学。生物氧化是秋季主要的CO损失项，而气体交换在春季几乎同样重要。春季较高的光生产和较慢的生物吸收导致[CO]分布模式和海气CO通量的秋季和春季差异很大。冷北方沃茨中的CO循环在数量和质量上都不同于暖海中的CO循环。
We investigated the distribution, photoproduction, microbial uptake, and air‐sea exchange of carbon monoxide (CO), a key photoproduct of chromophoric dissolved organic matter (CDOM), in open waters of the southeastern Beaufort Sea in autumn 2003 and spring 2004. Diurnal cycles of surface water CO concentration ([CO]) occurred in autumn but not in spring. In both seasons [CO] was well above air‐equilibrium at most stations (maximum of 12,500% saturation) and dropped with depth to undetectable levels below 50 m. Mean surface water [CO] and CO water‐column burdens (0‐50 m) were 0.45 nmol L−1 and 5.0 µmol m−2 in autumn and 4.7 nmol L−1 and 64.8 µmol m−2 in spring, and the sea‐to‐air CO flux was 33 times higher in spring. The efficiency of CO photoproduction correlated linearly with CDOM across the Mackenzie River estuary, the Mackenzie Shelf, and the Amundsen Gulf. Modeled water‐column CO photoproduction in spring was 15 times that in autumn (45.8 vs. 3.0 µmol m−2 d−1). Microbial CO uptake followed first‐order kinetics in autumn while Hill‐type, saturation, and inhibition kinetics were common in surface waters in spring. Bio‐oxidation was the dominant CO loss term in autumn while gas exchange was almost equally important in spring. Higher photoproduction and slower bio‐uptake in spring resulted in the wide autumn‐spring differences in the [CO] distribution pattern and air‐sea CO flux. CO cycling in cold northern waters differs both quantitatively and qualitatively from that in warmer seas.