Selected aspects of the current state of freshwater resources in the Murmansk region, Russia.

Aspects of reducing the resource potential of surface waters of the Murmansk region in the global climate change and the environment and their irrational use have been considered. Increase of aquatic environment toxicity, drastic restructuring of the structural and functional characteristics of aquatic communities, changes in trophic status of lakes, reducing the stability of freshwater ecosystems, increasing the risk of catastrophic degradation have been shown. Taking into account the regional peculiarities, some indicators of surface water quality in the Murmansk region have been proposed.

IS elements in Aliivibrio salmonicida LFI1238: occurrence, variability and impact on adaptability.

Insertion sequence (IS) elements are short, self-replicating DNA sequences that are capable of efficiently spreading over the host genome. Possessing varied integration specificity IS elements are capable of the irreversible inactivation of genes, which diversifies the pool of intact genetic determinants in host populations. In the current study, we performed a complex analysis of IS elements (Vsa IS) in the previously sequenced genome of Aliivibrio salmonicida LFI1238 and proposed a model of the spread of the Vsa IS elements over the genome of this microorganism. Along with the prediction of the integration sites for Vsa IS elements, the current study provides an overview of the properties of A. salmonicida IS elements, as well as information regarding their occurrence in different bacterial classes. An analysis of individual alleles of the IS elements has allowed us to depict a history of the accumulation of mutations and to describe distinctive microevolution lines for actively transposing Vsa IS elements in the genome of A. salmonicida LFI1238. Our results demonstrate the high importance of the dead end microevolution of actively transposing Vsa IS elements for the inactivation of genes in A. salmonicida LFI1238.

Heavy metal contents in whitefish (Coregonus lavaretus) along a pollution gradient in a subarctic watercourse.

Metallurgic industry is a source of serious environmental pollution related to the emission of heavy metals. Freshwater systems are focal points for pollution, acting as sinks for contaminants that may end up in fish and humans. The Pasvik watercourse in the border area between Finland, Norway and Russia is located in the vicinity of the Pechenganickel metallurgic enterprises, and the lower part of the watershed drains the Nikel smelters directly through Lake Kuetsjarvi. Heavy metal (Ni, Cu, Cd, Zn, Pb and Hg) concentrations in environment (water and sediments) and whitefish Coregonus lavaretus tissue (gills, liver, kidney and muscle) were contrasted between five lake localities situated along a spatial gradient of increasing distance (5-100 km) to the smelters. The heavy metal concentrations, in particular Ni, Cu and Cd, were highly elevated in Kuetsjarvi, but steeply declined with increasing distance to the smelters and were moderate or low in the other four localities. The study demonstrates that the majority of metal emissions and runoffs are deposited near the pollution source, and only moderate amounts of the heavy metal contaminants seem to be transported at further distances. Bioaccumulation of Hg occurred in all investigated tissues, and higher Hg concentrations in planktivorous versus benthivorous whitefish furthermore indicated that pelagic foraging is associated with higher levels of Hg biomagnification. Potential population ecology impacts of high heavy metal contaminations where mainly observed in whitefish in Kuetsjarvi, which showed depletions in growth rate, condition factor and size and age at maturation.