Valkova S.A. Selected aspects of the current state of freshwater resources in the Murmansk Region, Russia. Journal of Environmental Science and Health, Part A. 2017, V. 52, No 9, p. 921-929.

Downloaded by [Professor Vladimir Dauvalter] at 05:55 30 August 2017 924 N. A. KASHULIN ET AL. are undergoing drastic changes of structural and functional parameters of algocenoses, causing changes in the targeting and rate of succession, resulting from several factors including anthropogenic influence, which is the most important factor and forced by anomalous dynamics of the regional climate system. Before intensive industrial pollution, the phytoplankton and periphyton in bodies of water were dominated by dia­ toms and green (desmids) and golden algae. Those were typ­ ical communities of oligotrophic and ultra-oligotrophic waters in which an overall majority of species developed under conditions of low mineralization. At present, under conditions of eutrophication, the share of golden algae in algocenoses has decreased; for green algae, there has been a decrease in the share of desmid algae, and there has been an increase in the Volvocaceae and in the Fragilariaceae in the diatom community composition. Further, there has been a decrease in acidophilus species in the water bodies subjected to direct pollution and eutrophication. Changed hydrochem­ ical conditions and elevated total mineralization of water have resulted in increased growth of halophiles. The share of the Ulotrichophyceae has grown in the periphyton in pol­ luted rivers, along with the Fragilariaceae. The share of blue- green algae has increased in the structure of algocenoses, including their toxic forms. Periods of bloom of the Dinoph- ysis were observed; moreover, in waters with high trophic state, they often changed over to heterotrophic nutrition. The saprobity index has maximal values in the water bodies exposed to emissions from enterprises extracting and process­ ing apatite ores (JSK “Apatit”, Kovdor GOK), as well as those exposed to anthropogenic eutrophication (through wastewater flows). Elevated pH values also stimulate algal nuisance. Mean­ while, water bodies subjected to toxic load (heavy metals) or characterized by high metal concentrations have rather low val­ ues of the saprobity index S (at the level of oligosaprobic waters: 0.8-1.2). In such cases, correction of the saprobity index and its adjustment to water quality assessment or application restric­ tions are probably necessary. Changes in water trophic state are characterized by elevated quantitative indices of algal communities and a range of their deviations from mean values. It is a consequence of periodic growth of phytoplankton (“blooming of water”), which has occurred regularly in numerous water bodies in recent years. These processes are clearly seen in the largest lake of the region, the Imandra Lake. Its usual species of summer-period phytoplankton are the Peridiniales (Ceratium hirundinella f. hirundinella (O.F. Muller) Dujardin; Peridinium goslaviense Wolszynska) and the Cyanoprokaryota (Dolichospermum lemmermannii (Ricter) P.Wacklin, L.Hoffmann & J.Komare; D. flosaquae (Brebisson ex Bornet & Flahault) P.Wacklin, L.Hoffmann & J.Komarek). Meanwhile, under calm conditions, the cyanobacteria form a blanket on the water surface in bays and the Peridiniales in open parts of the water area. Blooms of the Peridiniales algae in windless weather colour the water sur­ face reddish. During blooms of blue-green algae, their biomass may achieve extremely high values, above 21 g/m3. Growth of cyanobacteria results in changes of hydrochemical features and optic and organoleptic properties of water. These periods are also correlated with the death of young whitefish. Zooplankton and zoobenthos communities undergo consid­ erable alterations. Decreasing biodiversity and the role of aboriginal zoobenthos species accompanied by an expansion of eurybiontic species from middle latitudes to the north have been recorded. Anthropogenic effects result in violations of structural organization of benthic communities, manifesting as reduced species diversity, elimination or reduction of steno- biontic species, reconstruction of dominating complex, and simplification of trophic and ethological structures. The pol­ luted areas are inhabited by communities of eurybiontic or tol­ erant species such as chironomids of the genera Chironomus, Procladius, Oligochaeta of the family Tubificidae, and some species of molluscs of the genera Lymnaea and Pisidium. Struc­ tural changes in the zooplankton community manifest as the reduction or elimination of sensitive relicts and typical repre­ sentatives of fauna of oligotrophic lakes (Leptodora kindtii Focke, Bythotrephes longimanus Leydig, Eudiaptomus gracilis Sars, Heterocope appendiculata Sars). They are replaced by small eurybiontic species with simple life-cycles and high reproduction rates, which gradually form the bulk of the domi­ nating complex (r-strategists): rotifers (in correlation with the main taxonomic groups Rotatoria/Cladocera/Copepoda, they make up a share of over 90% of the total number and biomass of organisms which testifies to disturbed and unstable state of the ecosystem). The average individual mass of zooplankter decreases (B/N). Reducing the Shannon species diversity index in numbers (HNbit/specimen) is not only a result of species num ­ ber reduction in the community but a result of the strengthened domination of a particular species and the formation of mono­ cultures from tolerant species. As seen from above, ecosystems of water bodies in this region are transforming away from their natural structure and will not return to their natural conditions. This idea is sup­ ported by the fish community, whose structural and functional organization is undergoing significant alterations. At present, the accumulation of pollutants in bodies of water is determined not only by local pollution sources but also by global air pollution and cross-border transport. The distribu­ tion of lead and mercury is an example of such processes. We have shown that there has been a steady increase in mercury concentrations in sediments and fish tissues in lakes of the Murmansk region and the Russian-Finnish and Russian- Norwegian border areas during the last decade, but this process has no connection with the activities of regional metallurgical plants.[13] However, nickel remains the major pollutant in the region. Nickel concentration at the level of 5-7 mg/gdry weight in kidneys of whitefish is critical, and exceeding this level causes serious pathologies in fish. Pollution of water bodies by heavy metals at a regional scale is interpreted by what can be proved by metal accumulation values (Cu, Zn) in fish from the refer­ ence area, which is comparable to and sometimes even higher than the values in fish from industrial areas (Lake Kuetsjarvi). Almost all bodies of water in the region are characterized by pathological changes in fish based on sub-lethal toxicity of the living environment, reducing their viability. Chronic effects of pollutants on fish organisms cause dysfunction of vital organs: gills, liver, kidneys, and gonads. The frequency and intensity of fish pathologies have clear-cut dependence on the technogenic load on the water body. If the pathological changes of inner