Spatial distribution characteristics of chlorophyll-a concentration in summer and its influencing factors in Lake Daihai of Mengxin Plateau

Kriging interpolation, correlation analysis, multiple linear step-to-step regression and principal component analysis was used to analyze the water sample data in Lake Daihai in August 2019. The results showed that the concentration of chlorophyll-a (Chl.a) decreased from the shore to the center of the lake. The spatial distribution characteristics of totoal nitrogen(TN), total phosphorus(TP), ammonia nitrogen(NH3-N), nitrate nitrogen(NO3--N) and orthophosphate (PO3-4-P) were similar to those of Chl.a, and the water quality of some region in Lake Daihai had reached heavy eutrophication during the sampling period; Chl.a was positively correlated with turbidity, TP, TN, suspended solids (SS), pH, NO-3-N, NH3-N, PO3-3-P and blue-green algae abundance (CYANO), significantly negatively correlated with dissolved oxygen (DO), positively correlated with electrical conductivity(Cond.), and negatively correlated with phosphorus-nitrogen ratio(TN/TP). The correlations between Chl.a and environmental factors were different in the different lake areas, and the linear regression equation in Lake Daihai was (formula present). There were differences in the effects of environmental factors on Chl.a content in different lake zones, and the correlation between Chl.a and environmental factors in each lake zone was also different. By comparing the correlation between Chl.a and environmental factors in Lake Daihai with other lakes in China, we found that the differences in the properties of various lakes and the nutrient contents were important factors in affecting Chl.a. In this study, the average TN/TP was 12.23 in Lake Daihai, as indicated that the growth of Chl.a was co-limited by nitrogen and phosphorus in summer. © 2023 Science Press. All rights reserved.