Estimating the Anthropogenic Impact on Water Bodies Using a Simulation Mathematical Model of Phosphorus System

A simulation model of the phosphorus system is used to study the ecosystems functioning in the Dautkul'skoe Reservoir and Shegekul Lake (Mezhdurech'e). Dependence of the internal flows (turnover) and normal annual concentrations of P forms in the water body on its external load onto the ecosystem is established. The budgets of P and its production–destruction flows (1993–1999), calculated using the model, are presented and analyzed. Comparison estimates are made for the anthropogenic impact on the water bodies of the southern Aral Sea region.     

Concentrations of heavy metals in bottom sediments of Lake Dautkul as an indicator of anthropogenic impact in the area south of the Aral Sea

Data on the microelement composition of bottom sediment and water samples from Lake Dautkul for recent years are presented. Concentrations of more than 30 chemical elements are determined using instrumental neutron-activation analysis. This allowed the authors to reveal the regularities in the distribution and accumulation of chemical elements in water and bottom sediments. It is shown that bottom sediments exhibit a cumulative effect and prolonged activity, which adversely affect the aquatic medium and can serve an indicator of anthropogenic impact on the area under consideration.     

Present-Day Conditions of Limnic Ecosystems in the Lower Reaches of the Amu Darya

Present-day state and the functioning conditions of different-type limnic ecosystems in the Amu Darya delta are examined. The ecosystems are subjected to anthropogenic impact at an abrupt decrease in freshwater inflow and a change to another source of water feed.     

The Role of Collecting Drainage Systems in the Formation of Chemical Composition of Lake Water in the Amu Darya Lower Reaches

As shown, drainage escape water forms a large category of surface water of the Amu Darya lower reaches, whose runoff varies from year to year and salinity varies within a year and over the period of many years. It is found that main collecting drains of the Amu Darya lower reaches are essential suppliers of salts and biogenic elements to lakes. The quality of drainage escape water is shown to be the basic factor of formation of the biological regime of limnetic ecosystems, and the migration of biogenes and large quantities of salts is shown to favor the formation of limnetic systems, which have a considerable level of pollution and are subjected to eutrophication.