Submarine groundwater discharge as an important nutrient source influencing nutrient structure in coastal water of Daya Bay, China
Submarine groundwater discharge as an important nutrient source influencing nutrient structure in coastal water of Daya Bay, China
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DOI：
10.1016/j.gca.2018.01.029
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发表时间：
2018-03
影响因子：
5
通讯作者：
Xuejing Wang;Xuejing Wang;Hailong Li;Hailong Li;C. Zheng;Jin-zhong Yang;Yan Zhang;Meng Zhang-;Zhanhui Qi;Kai Xiao;Xiaolang Zhang
中科院分区：
文献类型：
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作者：
Xuejing Wang;Xuejing Wang;Hailong Li;Hailong Li;C. Zheng;Jin-zhong Yang;Yan Zhang;Meng Zhang-;Zhanhui Qi;Kai Xiao;Xiaolang Zhang
作为沿海水体重要的营养源，海底地下水排放长期以来在中国大亚湾被忽视。本研究利用a224Ra质量平衡模型估算了该地区SGD及其相关营养物质的通量，并评估了SGD、底栖沉积物、当地河流和大气沉积对营养物质的贡献/重要性。of224Ra质量平衡的结果表明,该估计SGD范围从(2.76 ±1.43 ) × 106 m3 / d(1.03 ±0.53 ) × 平均107 m3 / d(6.32 ±2.42 ) × 106 m3 / d,约16乘以总当地河流的放电率。SGD对NO3-N的营养负荷估计为（1.05-1.99） × 105mol/d，对DIP的营养负荷为（4.04-12.16） × 103mol/d，对Si的营养负荷为（3.54-11.35） × 105mol/d。在这些考虑的营养来源中，我们发现SGD是Si和NO3-N的主要来源，分别占所有考虑来源的68%和42%。大气NO3-N通量与SGD相当。当地河流是DIP最重要的来源，占所有考虑来源的75%。高N:P比（NO3-N/DIP）为37.0的SGD不仅输送了大量的营养物质，而且改变了沿海水体的营养结构。根据DIP预算，初级产能评估为54-73 mg C/m2d，其中SGD约占总产量的30%。该研究表明，SGD是大亚湾近岸水域的重要营养来源，可能导致大亚湾初级生产和营养结构发生明显变化。
As an important nutrient source for coastal waters, submarine groundwater discharge (SGD) has long been largely ignored in Daya Bay, China. In this study, we estimate the fluxes of SGD and associated nutrients into this region using a224Ra mass balance model and assess the contribution/importance of nutrients by SGD, benthic sediments, local rivers, and atmospheric deposition. The results of224Ra mass balance show that the estimated SGD ranges from (2.76 ± 1.43) × 106m3/d to (1.03 ± 0.53) × 107m3/d with an average of (6.32 ± 2.42) × 106m3/d, about 16 times the total discharge rate of local rivers. The nutrient loading from SGD is estimated to be (1.05–1.99) × 105mol/d for NO3-N, (4.04–12.16) × 103mol/d for DIP, and (3.54–11.35) × 105mol/d for Si. Among these considered nutrient sources, we find that SGD is the primary source for Si and NO3-N, contributing 68% and 42% of all considered sources, respectively. The atmospheric NO3-N flux is comparable to that from SGD. The local rivers are the most important source for DIP, contributing 75% of all considered sources. SGD with high N:P ratio (NO3-N/DIP) of 37.0 delivers not only a large quantity of nutrients, but also changes nutrient structure in coastal water. Based on a DIP budget, primary productivity is evaluated to be 54–73 mg C/m2d, in which SGD accounts for approximately 30% of total production. This study indicates that SGD is a key source of nutrients to coastal waters and may cause an obvious change of primary production and nutrient structure in Daya Bay.