Impacts of environmental factors on Chlorophyll-a in lakes in cold and arid regions: A 10-year study of Wuliangsuhai Lake, China

Abstract

The study of seasonal variations in Chlorophyll-a (Chl.a) concentration and its influencing factors is particularly important for lake management. The study showed that there was a strong non-linear relationship between Chl.a and environmental factors in spring and autumn, whereas there was a strong linear relationship in summer and winter. Chl.a was redistributed during the ice period, and its concentration in water generally exceeded that in the ice sheet. Characteristics of the ice sheet, including thermal insulation, transparency, and nutrient migration into the water, positively impact phytoplankton growth and reproduction. Therefore, there was no significant difference between Chl.a in winter water and Chl.a in summer water. Although there were differences in the environmental factors affecting the temporal heterogeneity of Chl.a over the four seasons, conductivity (Cond.) showed a significant linear or nonlinear effect on Chl.a throughout the year, indicating its important role in regulating the growth and reproduction of phytoplankton. Environmental factors driving the spatial heterogeneity of Chl.a included the location of the water inlet channel, the distribution of Phragmites, and hydrodynamic conditions. These findings are valuable for understanding the seasonal variation of Chlorophyll-a and preventing eutrophication and algal blooms in cold and arid lakes.