[CH₄ Fluxes During the Algal Bloom in the Pengxi River]

Emissions of greenhouse gases in the Three Gorges Reservoir have been attracting attention in the recent years. This study was conducted to reveal the CH₄ emission and removal during the process of algal growth at different nitrogen and phosphorus concentrations in the Pengxi River in the Three Gorges Reservoir. In-situ field experiments were conducted in the Gaoyang Lake in Pengxi River. From April 22nd, 2016, to May 9th, 2016, different concentrations of nitrogen and phosphorus were added to different experimental chambers. Results showed that CH₄ emission decreased sharply from the first day of the experiment to the sixth day, and after that, CH₄ emission in the water samples with only added phosphorus were obviously recovered compared to the other treatment. In this experiment, algal biomass was influenced by different concentrations of N and P. The biomass of algae were not affected by N, but were promoted under suitable concentration of P, such as 1P, 10P, 1NP, and 10NP. When the P concentration was too high, the biomass of algae was also limited. The emission and removal of CH₄ in the experiment were significantly related to the addition of NO₃^--N.