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Erik Jeppesen

Effects of nitrate on phosphorus release from lake sediments

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  • Shuo Nan Ma, Chinese Academy of Sciences, Ningbo University
  • ,
  • Hai Jun Wang, Chinese Academy of Sciences
  • ,
  • Hong Zhu Wang, Chinese Academy of Sciences
  • ,
  • Miao Zhang, Chinese Academy of Sciences, University of Chinese Academy of Sciences
  • ,
  • Yan Li, Chinese Academy of Sciences
  • ,
  • Shi Jun Bian, Chinese Academy of Sciences
  • ,
  • Xiao Min Liang, Chinese Academy of Sciences
  • ,
  • Martin Søndergaard
  • ,
  • Erik Jeppesen

Phosphorus (P) release from sediment is a key process affecting the effectiveness of eutrophication mitigation. We hypothesized that high nitrate (NO3) input may have dual effect on sediment P release: reduce the sediment P release by improving the oxidation of sediment or promote P release by stimulating the growth of phytoplankton and increase the decomposition rates and oxygen consumption at the sediment water interface. To test the effect of different NO3 concentrations, we conducted a three-month experiment in 15 cement tanks (1 m3), with five targeted concentrations of NO3: control, 2 mg L−1, 5 mg L−1, 10 mg L−1, and 15 mg L−1. The results showed that: i) when NO3 was maintained at high levels: NO3≥5–7 mg L−1 (range of median values), there was no effect of NO3 on net P release from the sediment, likely because the positive effects of NO3 (increasing oxidation) was counteracted by a promotion of phytoplankton growth. ii) after NO3 addition was terminated NO3 dropped sharply to a low level (NO3≤0.4 mg L−1), followed by a minor P release in the low N treatments but a significant P release in the high N treatments, which likely reflect that the inhibition effect of NO3 on P release decreased, while the promotion effects at high NO3 concentrations continued. The results thus supported our hypotheses of a dual effect on sediment P release and suggest dose-dependent effect of NO3 loading on stimulating P release from the sediment, being clear at high NO3 exceeding 5–7 mg L−1.

Original languageEnglish
Article number116894
JournalWater Research
Volume194
ISSN0043-1354
DOIs
Publication statusPublished - Apr 2021

    Research areas

  • Alkaline phosphatase activity, Dual effect, Eutrophication, Oxidation of sediment, Sediment phosphorus release

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