Spatio-temporal variation and environmental drivers of chlorophyll a concentration and diatom community in four small urban lakes of Kunming, China.

Chlorophyll a (Chla) and diatom community structure are two indicators of lake water quality. In this study, we investigated the environmental parameters, chlorophyll a, and diatom community of four small urban lakes in Kunming (Beitan, Beihu, Nanhu and Longtan lakes in the campus of Yunnan Normal University) between March 2017 and December 2019. The results showed that the concentrations of total nitrogen (TN), total phosphorus (TP), and Chla in the four lakes showed significant seasonal fluctuation.

Long-term succession of diatom community under hydro-climatic fluctuations in Taiping Reservoir, Yunnan Province, China.

Under the background of regional climate warming, frequent fluctuation of water level caused by drought events and pollutant influx due to catchment development can directly threaten the ecological safety of reservoirs. Through the analysis of physical (particle size, loss on ignition), chemical (carbon, nitrogen), biological (diatom community) and other substitute indicators of sediment, combined with monitoring data and investigation data, we reconstructed the environmental changes in Taiping Reservoir in Yunnan Province from 1937 to 2018, and analyzed the succession characteristics of diatom community and its environmental impact factors. The grain size records indicated that the hydrodynamic condition of Taiping Reservoir was increased during the impounding period (1956-1984) and was steadily reduced thereafter, corresponding well with the documented history of reservoir construction and hydrologic regulation.