Effects of lake-basin morphological and hydrological characteristics on the eutrophication of shallow lakes in eastern China

Autor: Keli Jia, Jing Su, Xixi Wang, Jian Huang, Caole Li, Shouliang Huo, Beidou Xi, Qiujin Xu, Ting Zhang
Rok vydání: 2014
Předmět:
Zdroj: Journal of Great Lakes Research. 40:666-674
ISSN: 0380-1330
DOI: 10.1016/j.jglr.2014.04.016
Popis: The Yangtze River floodplain contains numerous oxbow or riverine lakes, all of which were openly connected with the Yangtze River or its major tributaries prior to 1950s. However, stresses resulting from human settlement and utilization of catchment resources have exerted great pressures on these lake ecosystems changing their morphology, connectivity and trophic state lakes. This study examined the interaction of these changes and their impact on eutrophication for 90 shallow lakes in eastern China in 2008 to 2011. TN and TP in the study lakes had negative relationships with mean water depth (Z mean ), but no single lake-basin characteristic was found to dominate chlorophyll-a (Chl-a) growth. Instead, water depth and surface area were found to interactively affect Chl-a concentrations in smaller lakes. That is, Chl-a concentration in the lakes with Z mean > 2 m and surface area (SA) ≤ 25 km 2 was significantly higher than that in relatively larger lakes with Z mean > 2 m and SA > 25 km 2 (p-value ≤ 0.038). Chl-a concentration was higher in the lakes located within the lower Yangtze River basin which had longer retention times, than in the lakes located within the middle Yangtze River basin, where flow velocity is relatively larger. As expected, the water quality was found to be better in the lakes hydraulically connected with rivers than in those isolated from the river. This study revealed that lake-basin morphology and hydrology dominated algal blooms in the highly eutrophic shallow lakes in eastern China.
Databáze: OpenAIRE