The ratio of nitrogen to phosphorus (N:P) is an important variable that has a close relationship with the ecological problems of nuisance algal blooms and eutrophication in aquatic environments in terms of nutrient limitation. Reservoirs generally have much higher retention efficiency for P than for N. This inherent dissimilarity in the N and P biogeochemical cycles likely results in N-P stoichiometric imbalance in downstream rivers and reservoirs, consequently causing an increase in the N:P ratio and aggravating P limitation. Here we determined the total N (TN) and total P (TP) concentrations in the cascade reservoirs of the Wujiang River and Lancangjiang River basins. The results show that TN:TP ratios in these 2 basins exhibited a common inverted V-shaped (A) pattern downstream. We found that P is not only retained by reservoirs more efficiently than N but is also replenished at faster rates than N given anthropogenic impacts; consequently, the N-P imbalance caused by these impoundments is alleviated within a short distance downstream because of inputs of anthropogenic nutrients. Our research suggests that construction of cascade reservoirs does not necessarily lead to strict P deficiency and anomalously high N:P ratios downstream. Publication name | INLAND WATERS, 8 (2):196-206; SI 10.1080/20442041.2018.1457853 2018 | Author(s) | Yang, Dan; Wang, Shilu; Lu, Weiqi; Xiang, Peng; Yang, Yuxue; Tan, Di; Guo, Mingwei; Yeager, Kevin M. | Corresponding author(s) | WANG Shilu wangshilu@vip.skleg.cn Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang, Guizhou, Peoples R China. | View here for the details
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