Long-Term Dynamics of Phosphorus in the Narochanskie Lakes and Factors Determining It

The Narochanskie Lakes (Batorino, Myastro, and Naroch) (Belarus) are a focus of many-year hydroecological studies. The modern evolution of the ecosystem of the lakes includes four stages: anthropogenic eutrophication in the 1970s, de-eutrophication because of nature protection measures in their drainage area in the 1980s, benthification because of invasion of mollusk-filterer Dreissena polymorpha Pallas in the 1990s, and the present-day state. Retrospective analysis of many-year dynamics of total phosphorus (1978-2010) in water of the Narochanskie Lakes is given for different stages of their ecosystems restructuring. The complex response of water bodies comprising a single ecosystem to external impacts is described and its causes are discussed.