Effects of basin nutrient discharge variations coupled with climate change on water quality in Lake Erhai, China

• Published in: Environmental science and pollution research international Vol. 27; no. 35; pp. 43700 - 43710
• Main Authors: Zhang, Jinpeng, Zhi, Mengmeng
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2020; Springer Nature B.V
• Subjects: Air temperature; Ammonia; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Chemical oxygen demand; Chemical precipitation; Climate change; Discharge; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental impact; Environmental science; Lakes; Nonlinear response; Nutrients; Phosphorus; Precipitation; Rainfall; Research Article; Trophic levels; Waste Water Technology; Water Management; Water Pollution Control; Water quality; Wind; Wind speed; Lake Erhai; Climate change; Lake Erhai; GAM (generalized additive model); Water quality; Basin nutrients
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-09179-0

In Lake Erhai, water quality was affected by the basin nutrient discharge and climate change. To analyze the relationships between the water quality (total nitrogen [TN], total phosphorus [TP], chemical oxygen demand [CODmn], ammonia [NH 4 ], and trophic level index [TLI]) and basin nutrient discharge (TNd, TPd, and CODd) combined with climate changes (air temperature [AT], precipitation [pre], wind speed [wind], and sunshine hours [SHs]), the generalized additive model (GAM) was employed to explore the nonlinear relationships with their interactions using data sets ranging from 1999 to 2012. Our findings revealed that the water quality in Lake Erhai deteriorated in the early twentieth century, and the basin discharge and AT appeared significant ( p  < 0.05) rising trends in a long time, while the precipitation decreased significantly ( p  < 0.05) in the study period. Single-factor GAM results indicated that the basin nutrient discharge was the main explanatory factor for the variations of TN and TP in lake, while precipitation was the main driver for CODmn and NH 4 . Besides, the water quality displayed nonlinear responses to the basin discharge, but all of the water quality variables went up as the emission levels increased in the lower range. The results showed that the water quality deteriorated in the lower rainfall, and TN rose as the AT increases, while TP was elevated accompanied by the ascending SHs there. The GAM interaction results suggested that the increase of AT and TPd had a promoting effect on TP in Lake Erhai. Stricter nutrient management measures should be implemented when the impacts of climate change are taken into account.