Quality Appraisal of Surface Waters on Fennoscandian Territory

Widely applied bioindication methods are analyzed based on the survey data of 1980–1996 for over 400 lakes and 300 watercourses in the northeastern Fennoscandia known to experience anthropogenic impact (toxification, acidification, eutrophication, and thermofication). Representative results of hydrobiological analysis of the quality of surface waters in areas with mixed toxic pollution (or anthropogenic acidification) may be obtained if methods are applied, different from the bioindication methods that are now accepted as standard for Russia, along with methods of biotesting natural waters. The saprotoxibity index, Kola biotic index, acidification estimation scale, biotesting methods were developed and adapted to regional conditions.     

Biotesting in the Assessment of Environmental and Toxicological State of Water Bodies in Lower Don River Basin

The toxicity of river water in the Lower Don basin was studied using biotesting with different biological objects. Water taken from most examined reaches of the Don and its tributaries was shown to exert toxic effect on crustaceans, algae, protozoa, and Rotifera.     

Functioning of the White Sea Ecosystem: Studying the Transformations of Organogenic Substances Using a Mathematical Model

Long-term observational data on hydrology, hydrochemistry, and hydrobiology are generalized and used for systems analysis of the biohydrochemical transformation processes of organic and biogenic substances in a marine environment. An ecological model with the systematized data is used to assess the annual dynamics of concentrations of organic and mineral N, P, and Si compounds and dissolved organic C and O₂ in eight water areas within the White Sea at specified conditions of water mass transport, river runoff, and water exchange with the Barents Sea. Variations in the biomasses of the major transformers of organic and biogenic substances (heterotrophic bacteria, phyto- and zooplankton, and microphytes) and their biological production were also evaluated. These characteristics serve as indicators of the state of the water environment, the presence of nutrients in it, and their import from outside.     

Copper (II) Speciation in a Freshwater Ecosystem

Results of chemico-biological experiments in a natural water body with the use of model systems with Cu (II) introduced in them at different proportions of its chemical forms (natural and simulated) in the solution. The model forms used in the experiments were Cu complexes with benzyl- and hexadecylmalonic acids, simulating low-molecular dissolved organic substances. The experimental conditions were chosen based on a preliminary calculation using WATEQ–4f program. The complexes of Cu with hexadecylmalonic acid are found to be absorbed by suspensions and removed into bottom sediment more actively than other Cu forms. The toxicity of introduced Cu for the phyto- and zooplanktonic communities is found to depend on the concentration of Cu²⁺ aqua-ions in the solution, in the presence of which the higher concentrations of complexes with malonic acids do not exert their toxic effect.     

Calculating Sediment Transport in the Coastal Zone of the Sea

The mathematical model described is intended for the prediction of anthropogenic sediment transport in the coastal zone of the sea. Calculation results are presented.     

Numerical Modeling of Ice Jams

A numerical model is proposed to describe the formation of ice jams under the effect of a release wave.     

Study of Heavy Metal Compound Transformations in Surface Waters

Results of studying Fe(III) hydrolysis and sorption of heavy metal compounds by organic matter of bottom sediments are discussed. The rate of Fe(III) hydrolysis is found to be largely determined by the concentration of dissolved organic substances. Values of kinetic parameters are obtained for heavy metal compounds sorption under static and dynamic conditions. Calculating the solubility of Fe, Cu, Cd, Zn, and Pb sulfides allowed the assessment of the amount of metals lost by bottom sediments due to the formation of metal complexes with dissolved organic substances contained in natural waters.     

Natural and Human-Induced Variations in Water and Sediment Runoff in the Danube River Mouth

Long-term natural and human-induced variations in water and sediment runoff in the Danube Delta head were studied on the basis of analysis of an extremely long series of observations (1840–2002). A considerable reduction of sediment runoff in the second half of the 20th century related to sediment accumulation in reservoirs was revealed. It was found that human activities had an insignificant impact on the water runoff variations and the period of 1961–2002 turned out to be abnormally water-abundant.     

Geographical and Ecological Characteristics of the Caspian Sea and Modern Tendencies in the Evolution of Its Ecosystem

The Caspian Sea is characterized in the geographic and ecological aspects, and the state of its ecosystem is estimated. The natural and anthropogenic processes that control the formation of the environmental conditions in the Caspian Sea and the distribution of principal commercial hydrobionts and their food items are analyzed. Data on modern tendencies in changes in the abiotic and biotic parameters of the ecosystem, their causes and mechanisms are summarized. Prospects of further changes related to the development of shelf fields of petroleum hydrocarbons are assessed.     

The State of Benthic Communities and Water Quality Evaluation in the Cheboksary Reservoir

Present-day quantitative and qualitative characteristics of the Cheboksary Reservoir have been investigated, and data on the biological diversity of benthic organisms have been compared to those of hydrobiological studies carried out in the region prior to the reservoir construction. The reservoir bottom communities include 75 species and forms of benthos. The reservoir water quality has been evaluated using different methods, including the determination of the degree of morphological structure abnormalities in chironomid larvae, regarded as sublethal indicators of bottom sediment pollution with toxic substances.