An evaluation of physical and biogeochemical processes regulating perennial suboxic conditions in the water column of the Arabian Sea
An evaluation of physical and biogeochemical processes regulating perennial suboxic conditions in the water column of the Arabian Sea
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DOI：
10.1029/2001gb001461
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发表时间：
2002-12
影响因子：
5.2
通讯作者：
V. Sarma
中科院分区：
文献类型：
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作者：
V. Sarma
根据模块海洋模式和最近收集的氧气数据，建立了阿拉伯海次表层（100-1000 m）的月氧气收支。模型结果与观测到的模式一致。模式结果表明，在阿拉伯海的氧最小区（OMZ）的调节主要是由物理过程与地球化学循环的氧。这导致水体常年处于亚氧状态，没有明显的季节性变化。OMZ的维护在非季风季节，当贫营养条件下盛行的表层，发生通过物理泵的氧气供应低，在季风期间产生的有机物的氧化持续耗氧量的帮助。另一方面，在季风期间，当发生较高的碳沉降通量时，通过物理泵的较高的氧通量来防止缺氧条件的形成。因此，阿拉伯海的亚氧条件是由季风生物泵调节的物理泵维持的。阿拉伯海中间沃茨（100-1000 m）的停留时间计算为6.5年，在季风期间快速更换。与非季风季节相比，季风期间的耗氧率也很高。基于水质量混合模型计算的碳再生速率、细菌碳需求和次表层中的电子传输系统活性与基于该模型估计的氧消耗速率一致。
Monthly oxygen budgets for the subsurface Arabian Sea (100–1000 m) are constructed on the basis of Modular Ocean Model and recently collected oxygen data. The model results are in agreement with the observed pattern. The model results revealed that oxygen minimum zone (OMZ) in the Arabian Sea is regulated largely by physical processes in association with biogeochemical cycling of oxygen. This results in perennial suboxic conditions in the water column with no significant seasonal variability. Maintenance of OMZ during nonmonsoon seasons, when oligotrophic conditions prevail in surface layers, occurs through low supply of oxygen by physical pump aided by continued oxygen consumption in the oxidation of organic matter produced during monsoons. On the other hand, formation of anoxic conditions during monsoons, when higher sinking fluxes of carbon occur, is prevented by higher flux of oxygen by the physical pump. Hence, suboxic conditions in the Arabian Sea are maintained by physical pump with moderation from monsoonal biological pump. The residence time of the Arabian Sea intermediate waters (100–1000 m) was computed to be 6.5 years with rapid replacement during monsoons. The oxygen consumption rates are also high during monsoons compared with nonmonsoon seasons. The carbon regeneration rates computed based on the water mass‐mixing model, bacterial carbon demand, and electron transport system activity in the subsurface layers are in agreement with oxygen consumption rates estimated based on this model.