Eutrophication-induced acidification of coastal waters in the northern Gulf of Mexico: Insights into origin and processes from a coupled physical-biogeochemical model
Eutrophication-induced acidification of coastal waters in the northern Gulf of Mexico: Insights into origin and processes from a coupled physical-biogeochemical model
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DOI：
10.1002/2016gl071881
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发表时间：
2017-01-28
影响因子：
5.2
通讯作者：
Wanninkhof, Rik
中科院分区：
文献类型：
--
作者：
Laurent, Arnaud;Fennel, Katja;Wanninkhof, Rik
从密西西比河/阿查法拉亚河系统进入墨西哥湾北部的营养物质促进了浮游植物的高产，并导致了高呼吸速率。呼吸作用加上水柱分层导致大陆架底部水域季节性夏季缺氧。除了消耗氧气外，呼吸作用还会产生二氧化碳（CO2），从而降低pH值并使海底酸化。在这里，我们提出了一个高分辨率的生物地球化学模型来模拟这种富营养化驱动的酸化，并研究了主要的潜在过程。该模型显示了墨西哥湾北部大陆架夏季酸化的大面积海底水域的反复发展，这与缺氧水域相吻合。以前没有报道过，酸化的水被限制在一个薄的底部边界层中，其中底栖生物代谢过程产生的二氧化碳占主导地位。尽管饱和状态降低，酸化后的水相对文石仍然是过饱和的。
Nutrient inputs from the Mississippi/Atchafalaya River system into the northern Gulf of Mexico promote high phytoplankton production and lead to high respiration rates. Respiration coupled with water column stratification results in seasonal summer hypoxia in bottom waters on the shelf. In addition to consuming oxygen, respiration produces carbon dioxide (CO2), thus lowering the pH and acidifying bottom waters. Here we present a high-resolution biogeochemical model simulating this eutrophication-driven acidification and investigate the dominant underlying processes. The model shows the recurring development of an extended area of acidified bottom waters in summer on the northern Gulf of Mexico shelf that coincides with hypoxic waters. Not reported before, acidified waters are confined to a thin bottom boundary layer where the production of CO2 by benthic metabolic processes is dominant. Despite a reduced saturation state, acidified waters remain supersaturated with respect to aragonite.