4. Conclusions
In this study, SRP release and uptake experiments were conducted, and a 32P radiotracer was used to evaluate the direct and indirect effects of benthic algae on the SRP release from sediments. The following conclusions were drawn:
(1) Benthic algae could effectively reduce SRP release from sediments. At the seventh day in the SRP release experiment, the 32P activity in the water of the release treatment group with benthic algae was only 4% of that in the control group.
(2) In the SRP uptake experiment, large amounts of SRP were taken up by benthic algae in the first hour when the SRP concentration was high, and the decrease rate of the 32P activity was 14%. However, the decrease rate did not change with time, indicating that the benthic algae were saturated with SRP in a short time.
(3) The indirect way of oxidizing the upper layer of sediments through the photosynthesis of benthic algae plays an important role in reducing the SRP release from sediments. In addition, loss of benthic algae due to eutrophication increases the potential negative effects on water quality.