S Florida Water Management Dist, W Palm Beach, FL 33416 USA; Hiroshima Univ, Dept Civil & Environm Engn, Hiroshima 739, Japan; Chinese Acad Sci, Donghu Expt Stn Lake Ecosyst, Wuhan 430072, Peoples R China; Hokkaido Univ, Grad Sch Environm Earth Sci, Sapporo, Hokkaido 060, Japan; Natl Inst Environm Studies, Div Reg Environm, Tsukuba, Ibaraki 305, Japan; Shinshu Univ, Suwa Hydrobiol Stn, Nagano 392, Japan
We compared the nutrient dynamics of three lakes that have been heavily influenced by point and non-point source pollution and other human activities. The lakes, located in Japan (Lake Kasumigaura), People's Republic of China (Lake Donghu), and the USA (Lake Okeechobee), all are relatively large(>30 km(2)), very shallow (<4 m mean depth), and eutrophic. In all three lakes we found strong interactions among the sediments, water column, and human activities. Important processes affecting nutrient dynamics included nitrogen fixation, light limitation due to resuspended sediments, and intense grazing on algae by cultured fish. As a result of these complex interactions, simple empirical models developed to predict in-lake responses of total phosphorus and algal biomass to external nutrient loads must be used with caution. While published models may provide 'good' results, in terms of model output matching actual data, this may not be due to accurate representation of lake processes in the models. The variable nutrient dynamics that we observed among the three study lakes appears to be typical for shallow lake systems. This indicates that a greater reliance on lake-specific research may be required for effective management, and a lesser role of inter-lake generalization than is possible for deeper, dimictic lake systems. Furthermore, accurate predictions of management impacts in shallow eutrophic lakes may require the use of relatively complex deterministic modeling tools. (C) 2000 Elsevier Science Ltd. All rights reserved.
K.E. Havens; T. Fukushima; P. Xie; T. Iwakuma; R.T. James; N. Takamura; T. Hanazato; T. Yamamoto.Nutrient dynamics and the eutrophication of shallow lakes Kasumigaura (Japan), Donghu (PR China), and Okeechobee (USA),ENVIRONMENTAL POLLUTION,2001,111(2):263-272