Retention of nitrogen and phosphorus in Lake Chaohu, China: implications for eutrophication management

• Published in: Environmental science and pollution research international Vol. 27; no. 33; pp. 41488 - 41502
• Main Authors: Wang, Yanping, Kong, Xiangzhen, Peng, Zhaoliang, Zhang, Hui, Liu, Gang, Hu, Weiping, Zhou, Xiangqian
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2020; Springer Nature B.V
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; China; Earth and Environmental Science; Ecotoxicology; Efficiency; Environment; Environmental Chemistry; Environmental Health; Environmental Monitoring; Environmental science; Eutrophication; Hydrology; Lakes; Loads (forces); Mass balance; Nitrogen; Nitrogen - analysis; Nutrient balance; Nutrient cycles; Nutrient loading; Nutrient retention; Nutrients; Phosphorus; Phosphorus - analysis; Research Article; Retention; Retention capacity; Seasonal variations; Waste Water Technology; Water Management; Water Pollution Control; Water temperature; China; Nutrient retention efficiency; Seasonal pattern; Internal loading; Lake Chaohu; Nutrient budget; Lake eutrophication
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-10024-7

Nutrient retention is an important process in lake nutrient cycling of lakes and can mitigate lake eutrophication. However, little is known about temporal lake nutrient retention efficiency and it varies due to changes in hydrological, ecological, and nutrient inputs to lake waters. Quantitative information about seasonal lake N and P retention is critical for developing strategies to reduce eutrophication in lake systems. This study investigated TN and TP retention efficiencies and retention masses using water and mass balance calculations, and statistically analyzed the seasonal variability of nutrient retention in Lake Chaohu, China, from 2014 to 2018. Lake Chaohu experienced large amounts of external loads inputs (23.2 g N m −2  year −1 and 1.3 g P m −2  year −1 ), and approximately 58% TN and 48% TP were retained annually. The lake acted more as a sink for N than for P. The mean annual TP retention efficiency decreased ( P  < 0.05) over the study period, indicating that TP retention capacity was gradually exceeded. Seasonal variability of TN and TP retention efficiency was high and ranged from − 18.7 to 144.1% and from − 58.8 to 170.7%, respectively, over the five study years. The internal P loads over the study period were equivalent to roughly 9% of the total external loads. The annual nutrient retention efficiency of TN and TP increased with hydraulic residence time, while water temperature was an essential factor for the contrasting seasonal variation patterns of TN and TP retention efficiencies.