Impoundment-induced nitrogen–phosphorus imbalance in cascade reservoirs alleviated by input of anthropogenic nutrients

Dan Yang, Shilu Wang, Weiqi Lu, Peng Xiang, Yuxue Yang, Di Tan, Mingwei Guo, Kevin M. Yeager

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


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 (∧) 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.

Original languageEnglish
Pages (from-to)196-206
Number of pages11
JournalInland Waters
Issue number2
StatePublished - Apr 3 2018

Bibliographical note

Publisher Copyright:
© 2018, © 2018 International Society of Limnology (SIL).


  • Lancangjiang River
  • N-P imbalance
  • TN:TP ratio
  • Wujiang River
  • cascade reservoirs
  • nutrient retention

ASJC Scopus subject areas

  • Aquatic Science
  • Water Science and Technology


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