Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, PR China.
Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, PR China; Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, PR China; Key Laboratory of Marine Eco-Environmental Science and Technology, Ministry of Natural Resources, Qingdao, 266061, PR China.
Environ Pollut. 2022 Jan 15;293:118601. doi: 10.1016/j.envpol.2021.118601. Epub 2021 Nov 27.
Riverine carbon (C) composition and export are closely related to changes in the coastal environment and climate. Excessive C inputs from rivers to seas and their subsequent decomposition could result in harmful algal blooms and ecosystem degradation in the coastal sea. In this study, we explored the C transportation and composition in the 24 major rivers of the Bohai Sea (BS) Rim based on the investigation of dissolved organic carbon (DOC), carbon stable isotopes (δC) and chromophoric dissolved organic matter (CDOM). The results showed that the riverine DOC concentrations were high (10.6 ± 6.04 mg/L) in the BS Rim compared with the DOC levels in the main rivers in Eastern China (4.98 ± 2.45 mg/L). The δC ranged from -28.29‰ to -25.32‰ in the rivers of the BS Rim, suggesting that the DOC mainly originated from riverine plankton, soil organic matter mainly induced by C3 plants, and sewage. The excitation-emission matrix fluorescence spectroscopy of the CDOM indicated that a soluble, microbial by product-like material accounted for the largest proportion (approximately 40%) of CDOM in these rivers and that CDOM mainly originated from autochthonous riverine sources with high protein-like components. The rivers in the BS Rim transported approximately 0.55 Tg C of DOC to the BS each year, with more than 70% of reactive C based on the CDOM composition. The DOC yields in terms of unit drainage area transported from the small rivers to the BS were higher compared to those of the larger rivers in the world, which indicated that the small rivers in the Bohai Rim could be an important source of the C in the BS. This study would enrich our understanding of environmental evolution in coastal areas with numerous small rivers.
渤海湾（BS）流域 24 条主要河流的碳输运及其组成特征
河流碳（C）组成及其输出与沿海环境和气候变化密切相关。过量的 C 从河流输入海洋及其随后的分解可能导致沿海海域有害藻类的爆发和生态系统的退化。本研究基于溶解有机碳（DOC）、碳稳定同位素（δC）和有色溶解有机 matter（CDOM）的调查，探讨了渤海湾（BS）流域的 C 输运及其组成特征。结果表明，BS 流域河流的 DOC 浓度较高（10.6±6.04mg/L），明显高于中国东部主要河流的 DOC 水平（4.98±2.45mg/L）。BS 流域河流的 δC 值范围为-28.29‰至-25.32‰，表明 DOC 主要来源于河流浮游生物、土壤有机物质，主要由 C3 植物诱导产生，以及污水。CDOM 的激发-发射矩阵荧光光谱表明，一种可溶性、微生物副产物样物质占这些河流 CDOM 的最大比例（约 40%），并且 CDOM 主要来源于具有高蛋白质样成分的自生源河流源。BS 每年从流域输送约 0.55Tg C 的 DOC，根据 CDOM 组成，其中超过 70%是活性 C。从小河流向 BS 输送的单位流域面积的 DOC 产率高于世界上较大河流的产率，这表明渤海流域的小河可能是 BS 中 C 的一个重要来源。本研究将丰富我们对众多小河径流入海量小河流的沿海地区环境演化的认识。
