CSIR-National Institute of Oceanography, 176 Lawsons Bay Colony, Visakhapatnam, India.
Centre for Marine Living Resources and Ecology, Kochi, India.
Environ Sci Pollut Res Int. 2024 Aug;31(38):50820-50838. doi: 10.1007/s11356-024-34509-x. Epub 2024 Aug 5.
Submarine groundwater drainage (SGD) changes the elemental composition of the neighboring coastal ocean and impacts the biogeochemical cycles. To examine the seasonal and spatial variability in dissolved organic carbon (DOC) and labile organic compound biochemical compounds like dissolved carbohydrates (TDCHO), dissolved proteins (TDPRO), and dissolved free amino acid (TDFAA) concentrations during the dry and wet periods, groundwater samples were taken at 90 locations (180 samples) along the Indian coast. The mean DOC contents in Indian coastal groundwaters were more significant than the global mean values. DOC, TDCHO, TDPRO, and TDFAA concentrations are higher during wet than dry periods. The DOC and labile organic compound showed a substantial positive association with soil organic carbon, and respective labile compounds in soil, population, and land usage and poor relation with woodland territories, implying that soil organic compounds leaching is a source of DOC and other labile organic compounds into the groundwater. DOC and other labile compounds concentrations were linearly associated with population density, land usage, and sewage production, demonstrating that anthropogenic activities tightly regulate the formation of DOC in groundwater. During the wet and dry periods, total labile organic compounds (TDCHO, TDFAA, and TDPRO) constituted 21% and 10.5% of DOC, respectively. Compared to the wet time, more aromatic compounds accumulated during the dry season but were less bioavailable. SGD DOC flux contributed 2-7% of riverine DOC flux to the coastal ocean. The SGD flux from the Indian subcontinent to the nearby northern Indian Ocean accounts for approximately 2% of the worldwide SGD flux. The effect of DOC flux via SGD on coastal bacterial activity, the plankton food web, and the oxygen minimum zone must be studied.
地下水抽取改变了邻近沿海海域的元素组成，并影响了生物地球化学循环。为了研究干旱和湿润期期间溶解有机碳 (DOC) 和易变有机化合物生化化合物（如溶解碳水化合物 (TDCHO)、溶解蛋白质 (TDPRO) 和溶解游离氨基酸 (TDFAA)) 的浓度的季节性和空间变异性，沿印度海岸的 90 个地点（180 个样本）采集了地下水样本。印度沿海地下水中的平均 DOC 含量高于全球平均值。在湿润期，DOC、TDCHO、TDPRO 和 TDFAA 浓度高于干旱期。DOC 和易变有机化合物与土壤有机碳呈显著正相关，而各自的易变化合物与土壤、人口和土地利用呈显著正相关，与林地的关系较差，这表明土壤有机化合物淋溶是 DOC 和其他易变有机化合物进入地下水的来源。DOC 和其他易变化合物的浓度与人口密度、土地利用和污水产量呈线性相关，表明人为活动严格控制了地下水中 DOC 的形成。在湿润和干燥期，总易变有机化合物（TDCHO、TDFAA 和 TDPRO）分别占 DOC 的 21%和 10.5%。与湿润期相比，干燥季节积累了更多的芳香族化合物，但生物可利用性较低。SGD 的 DOC 通量占沿海海洋河流 DOC 通量的 2-7%。从印度次大陆到附近北印度洋的 SGD 通量约占全球 SGD 通量的 2%。必须研究通过 SGD 输送的 DOC 对沿海细菌活动、浮游生物食物网和缺氧区的影响。
