Drivers of Oxygen Consumption in the Northern Gulf of Mexico Hypoxic Waters—A Stable Carbon Isotope Perspective
Drivers of Oxygen Consumption in the Northern Gulf of Mexico Hypoxic Waters—A Stable Carbon Isotope Perspective
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DOI：
10.1029/2018gl078571
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发表时间：
2018-10
影响因子：
5.2
通讯作者：
Hongjie Wang;Xinping Hu;N. Rabalais;J. Brandes
中科院分区：
文献类型：
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作者：
Hongjie Wang;Xinping Hu;N. Rabalais;J. Brandes
我们使用孵化（沉积物和水）和三端元混合模型研究了墨西哥湾北方（nGoM）矿化有机碳（δ 13 COCx）的稳定碳同位素组成。孵化沉积物中的δ 13 COCx为−18.1‰ ± 1.3‰，孵化近表层和近底层沃茨中的δ 13 COCx随盐度而变化，从半咸水到全浓度海湾水的范围为−30.4‰至−16.2‰。盐度>23时，δ 13 COCx的平均值为−18.6‰ ± 1.8‰。基于以往夏季低氧巡航（2011年、2012年、2014年、2015年和2016年）收集的多年数据集的三端元混合模型表明，跨越nGoM（5-50米）的近底沃茨中的δ 13 COCx为−18.1‰ ± 0.6‰。从三个独立的方法，即水柱，表层沉积物和混合模型的孵化得到的δ 13 COCx的接近一致，表明海洋来源的13 C富集有机质在夏季nGoM陆架近底层水和底栖氧消耗中起主导作用。
We examined the stable carbon isotopic composition of remineralized organic carbon (δ13COCx) in the northern Gulf of Mexico (nGoM) using incubations (sediment and water) and a three‐end‐member mixing model. δ13COCx in incubating sediments was −18.1‰ ± 1.3‰, and δ13COCx in incubating near‐surface and near‐bottom waters varied with salinity, ranging from −30.4‰ to −16.2‰ from brackish water to full‐strength Gulf water. The average δ13COCx was −18.6‰ ± 1.8‰ at salinity >23. A three‐end‐member mixing model based on a multiyear data set collected in previous summer hypoxia cruises (2011, 2012, 2014, 2015, and 2016) suggested that δ13COCx in near‐bottom waters across the nGoM (5–50 m) was −18.1‰ ± 0.6‰. The close agreement of δ13COCx obtained from the three independent approaches, that is, incubations of water column, surface sediments, and mixing model, suggests that 13C‐enriched organic matter of marine origin played the dominant role in near‐bottom water and benthic oxygen consumption in the nGoM shelf in summer.