Journal of East China Normal University(Natural Science) ›› 2021, Vol. 2021 ›› Issue (2): 63-72.doi: 10.3969/j.issn.1000-5641.2021.02.007

• Estuary and Coastal Research • Previous Articles     Next Articles

Changes in chlorophyll and nutrients in reservoirs of the Changjiang River basin: The “biological filter” effect

Meng TONG1, Maotian LI1,2,*(), Shujie NIU1, Xiaoqiang LIU1, Mudong LIN1, Huiting GUO1, Lijun HOU1   

  1. 1. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
    2. Institute of Eco-Chongming, Shanghai 202162, China
  • Received:2019-11-19 Online:2021-03-25 Published:2021-04-01
  • Contact: Maotian LI


The biological filtering effect of reservoirs has become an area of focus for environmental science. We conducted an in situ survey, with different upstream retention times, of chlorophyll-a (Chl.a) and nutrients at the Zhexi, Zhelin, Hualiangting, and Yahekou reservoirs. We found that: ① In the vertical direction, Chl.a in each reservoir had the largest subsurface layer and generally decreased downward, resulting in upper nutrients assimilated by algae and an average vertical retention rate of DIN, DIP, and DSi of the reservoirs at 6.29%, 14.92%, and 8.60%, respectively. ② The concentration of Chl.a and the biomass of phytoplankton generally decreased from upstream to downstream, resulting in lots of nutrients assimilated by algae upstream, and the average horizontal retention rate of DIN, DIP, and DSi of the reservoirs at 26.53%, 39.89%, and 31.70%, respectively. ③ The total average retention rate of DIN, DIP, and DSi of the four reservoirs were 32.82%, 54.80%, and 40.30%, respectively. ④ The concentration of DIP decreased gradually with increases in the reservoir’s retention time; in fact, the concentration of DIP even decreased to 0.1 μmol/L, i.e. the growth of phytoplankton was fully limited by DIP.

Key words: reservoir, subsurface chlorophyll maximum, nutrient retention, biological filtering

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