Abstract
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 language | English |
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Pages (from-to) | 196-206 |
Number of pages | 11 |
Journal | Inland Waters |
Volume | 8 |
Issue number | 2 |
DOIs | |
State | Published - Apr 3 2018 |
Bibliographical note
Funding Information:We thank two anonymous reviewers for the helpful comments on this manuscript. This research was supported by the National Key Research and Development Program of China through Grant No. 2016YFA0601003, Program Foundation of Institute for Scientific Research of Karst Area of NSFC-GZGOV through Grant No. U1612442, and the National Natural Science Foundation of China (Grant Nos 91547117 and 41373137).
Publisher Copyright:
© 2018, © 2018 International Society of Limnology (SIL).
Keywords
- Lancangjiang River
- N-P imbalance
- TN:TP ratio
- Wujiang River
- cascade reservoirs
- nutrient retention
ASJC Scopus subject areas
- Aquatic Science
- Water Science and Technology