Abstract

Endogenous phosphorus (P) release from sediments is an important factor to cause eutrophication and, hence, algal bloom in lakes in China. Algal decomposition depletes dissolved oxygen (DO) and causes anaerobic conditions and therefore increases P release from sediments. As sediment P release is dependent on the iron (Fe) cycle, electron acceptors (e.g., NO3-, SO42-, and Mn4+) can be utilized to suppress the reduction of Fe3+ under anaerobic conditions and, as such, have the potential to impair the release of sediment P. Here, we used a laboratory experiment to test the effects of FeCl3, MnO2, and KNO3 on soluble reactive phosphorus (SRP) concentration and related chemical variables in the overlying water column during algal decomposition at different algal densities. Results showed that algal decomposition significantly depleted DO and thereby increased sediment Fe-bound P release. Compared with the control, addition of FeCl3 significantly decreased water SRP concentration through inhibiting sediment P release. Compared with FeCl3, addition of MnO2 has less potential to suppress sediment P release during algal decomposition. Algal decomposition has the potential for NO3- removal from aquatic ecosystem through denitrification and by that alleviates the suppressing role of NO3- on sediment P release. Our results indicated that FeCl3 and MnO2 could be efficient in reducing sediment P release during algal decomposition, with the strongest effect found for FeCl3; large amounts of NO3- were removed from the aquatic ecosystem through denitrification during algal decomposition. Moreover, the amounts of NO3- removal increased with increasing algal density.

Keywords

Algal bloom; Electron acceptor; Phosphorus; Internal loading; Taihu Lake

Published in

Environmental Science and Pollution Research
2015, Volume: 22, number: 24, pages: 19507-19517

SLU Authors

• Kardol, Paul

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

SDG6 Ensure availability and sustainable management of water and sanitation for all
SDG14 Conserve and sustainably use the oceans, seas and marine resources for sustainable development


UKÄ Subject classification

Forest Science


Publication identifier

DOI: https://doi.org/10.1007/s11356-015-5057-7

Permanent link to this page (URI)

https://res.slu.se/id/publ/69124