KMS Chongqing Institute of Green and Intelligent Technology, CAS
| Dams altered Yangtze River phosphorus and restoration countermeasures | |
Zhou, Jianjun1; Zhang, Man1; Li, Zhe2
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| 2018 | |
| 摘要 | Phosphorus(P), as a limiting and vital macronutrient in global freshwaters, circulates mainly with sediment through rivers. In this paper, we analyzed and summarized the regime of P and its variations that induced by dams burgeoning in the upper Yangtze River basins in recent decades. We revealed that more than 91% of the P flux is in particulate form, among which the potential dissolvable bio-active P (BAP) can exceed the total load that discharged from the riparian basins. The P is closely correlated with sediment and we estimated that reservoirs have by more than 3 quarters of it sequestrated. Previously, the BAP was mostly absorbed by sediment and flushed by floods to the estuary, where it supported a flourishing saline bio-ecosystem at the same time, with minor residuals in the lowland freshwaters. However, this nature endowed regime was upset by the sequestration of reservoirs that reallocated reversely the background P as inner pollution for the freshwater corridors and snatched the inherent nutrient for ecosystem of the estuary. Moreover, the resultant clear-stream lost its buffering effect that sediment regulates P and the lowland freshwater becomes more vulnerable with lowered environmental capacity. Accounting for the actual eutrophic status, the pool elevated dissolvable P level may also add potential risks in stimulating harmful algal blooms and hypoxia to the Three Gorges Reservoir and others. On another hand, in order to keep a basin wide consistent monitoring and criterions in P control from water to water and we can evaluate the harmful effect of dams more objectively, we recommend urgently to correct the present P analysis regulation, which requires P extraction from water samples after 30 min settling, that can lose a significant amount of P. Finally, we proposed to restore the downstream biogenic-substance and eliminate the in-pool accumulating P contamination through successive slurry dredging from reaches in front of the dams. © 2018 by Journal of Lake Sciences. |
| DOI | 10.18307/2018.0401 |
| 发表期刊 | Hupo Kexue/Journal of Lake Sciences
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| ISSN | 10035427 |
| 卷号 | 30期号:4页码:865-880 |
| 收录类别 | EI |
| 语种 | 中文 |
