Specific features of accumulation of Cu,Ni, Zn,Cd, and Hg in two whitefish <Emphasis Type="Italic">Coregonus lavaretus</Emphasis> (L.) morphs inhabiting the Inari-Pasvik lacustrine-riverine system

The spatial regularities of the accumulation of heavy metals in two ecological morphs of whitefish of the Pasvik River (northern Fennoscandia) under long-term pollution have been investigated. It was revealed that the accumulation of priority pollutants (Ni and Cu) in fish declines the further you go from the source of pollution. The concentration of Hg in the tissues of fish from the Pasvik River was determined for the first time. It was found that metal accumulation depends on the ecological morphs of the fish, the natural conditions of the waterbodies, and the intensity of pollution. The specific features of heavy-metal distribution in the “bottom sediment-fish organism” system were determined. These may indicate the heterogeneity of the pollution processes of the Pasvik system of waterbodies.     

Activity of cytochrome P-450 in whitefish <Emphasis Type="Italic">Coregonus lavaretus</Emphasis> and pike <Emphasis Type="Italic">Esox lucius</Emphasis> from subarctic water bodies exposed to waste water of mining enterprises

The response of hydroxylase activity of cytochrome P-450 from the microsomes of fish liver depends on fish species and on the kind of pollution. Differences in activity of the enzyme in whitefish Coregonus lavaretus and Pike Esox lucius depend on differences in ecology and in sensitivity of species to industrial effluents. Whitefish reacted to pollution by decrease in the activity of cytochrome P-450. In pike the activity of the enzyme increased under the influence of industrial wastewater. Males of both species are less resistant than females to the aforementioned pollutants. With consideration to the obtained results, the determination of activity of cytochropme P-450 may be recommended as the indicator of pollution level of the aquatic environment with industrial waste products, including those containing heavy metals.     

Ontogenetic niche shifts and resource partitioning in a subarctic piscivore fish guild

The feeding ecology of three piscivorous fish species (perch (Perca fluviatilis), pike (Esox lucius) and burbot (Lota lota)), was studied in the subarctic Pasvik watercourse (69 °N), northern Norway and Russia. All three species primarily occupied the benthic habitats in the watercourse. Perch and burbot exhibited distinct ontogenetic niche shifts in food resource use, perch changing from a dominance of zooplankton to zoobenthos to fish, and burbot from zoobenthos to fish. Fish prey dominated the diet of all the investigated size-classes of pike, but small-sized pike (<20 cm) were not represented in the sample. Fish prey size was positively related to predator size in all three species. Whitefish (Coregonus lavaretus) was the dominant prey of pike and large-sized burbot and perch. Nine-spined sticklebacks (Pungitius pungitius) was also an important prey and appeared to be a dietary stepping-stone enhancing the transition from invertebrate feeding to consumption of large-sized whitefish prey for all three predators. A cluster analysis separated the different size groups of the three predator species into five functional feeding groups, most of them containing two or all three species. Within these feeding groups, and especially among the piscivorous size-classes, there was a strong and significant interspecific overlap in prey selection, and the dietary similarities between the species were in general much larger than the intraspecific similarities between ontogenetic stages. All three piscivorous species are important top predators in the aquatic food web of the watercourse, and their ontogenetic diet shifts and resource partitioning patterns generate a substantial food web complexity in this subarctic ecosystem.     

Linear growth of sparsely rakered whitefish <Emphasis Type="Italic">Coregonus lavaretus</Emphasis> (Coregonidae) of the Imandra Lake (Murmansk oblast)

This paper studies the properties of linear growth in sparsely rakered whitefish Coregonus lavaretus in the stretches of the large subarctic Imandra Lake, which are characterized by the diversity of habitat conditions and anthropogenic stress levels. The groups of sparsely rakered whitefish that are confined to different areas of the lake are marked out based on the properties of growth, trophic status, and anthropogenic stress intensity. A direct relationship of the linear growth in whitefish with the age of sexual development and trophic level of its habitats is found.     

Extremely rapid effects of polyunsaturated fatty acids and N-acetylglucosamine on free-radical metabolism in cultured potato plant cells

The effects of arachidonic and linoleic acids, separately and in co-operation with N-acetylglucosamine oligomers, on Solanum tuberosum plant suspension cell cultures were investigated in terms of the fluorescent oxygen-activated-species-sensitive dye 2',7'-dichlorofluorescin diacetate. The inductors used triggered extremely rapid (within 2-10 min) generation of H(2)O(2) in the cells; the majority was expressed in cultures treated with combined polyunsaturated fatty acid and N-acetylglucosamine oligomers. The stimulation of free-radical generation may be related to defensive mechanisms modulating a plant-pathogenic-micro-organism interaction.     

Flow of heavy metals (Ni and Cu) in the catchment area of a subarctic lake

This paper considers methodological approaches to estimating the flow, balance, and accumulation of heavy metals (HMs) in a lake under conditions of long-term air pollution. Using the example of Chunozero Lake in the Lapland State Biospheric Reserve in Murmansk region, the accumulation of HMs in sediments is estimated for over a 70-year period of activity of a metallurgical mining enterprise (GMK Severonikel). The thickness of polluted sediments in a greater part of the lake water area averages 2 cm, and the average sedimentation rate for the last 20 years is 1 mm/year. Metals accumulated in lake sediments can indicate a danger of pollution in the future, particularly if processes of lake eutrophication develop. Due to the peculiar properties of substance flow to the Chunozero, the running type of water-mass movement, and the elongated form of the lake, only about 3% of HMs that enter the catchment area accumulate in sediments, in contrast to Imandra Lake (which has the largest area), where the accumulation of HMs reaches 55% owing to the fact that they enter mainly in the composition of wastewater and the low velocities of water flow.     

Histopathological characteristics of Coregonus fishes under the impact of metal industry

This article provides results from monitoring studies of the state of common whitefish (Coregonus lavaretus L.) inhabiting the border Pasvik River and a number of lakes of Northern Fennoskandia. The water catchment area is subject to a significant contamination by coper, nickel, and sulfur dioxide due to the airborne transport of emissions from the Pechenganikel smelter. The ecological situation near the smelter is evaluated as very unfavorable and requires constant control, including the monitoring of aquatic systems. We used histopathologies of gills, liver, and kidneys as biomarkers to diagnose the state of sparsely rakered whitefish. Changes in their cellular structure were diagnosed and classified. The presence of the revealed abnormalities is associated with long-term aerotechnogenic stress on the investigated water bodies. The possibility of using the obtained data for assessing water quality has been considered.     

Chronobiological analysis of subarctic features of long-term dynamics of biological processes

The analysis of a large number of chronobiological observations (heliospheric modulations, cosmophysical factors, weak low-frequency electromagnetic influences, etc.) allows us to make a conclusion about the possibility of direct and indirect exogenous (relative to the biosphere) modulations of biological processes in avroral and arctic zones. A nonequivalence of various seasons for the performance of introduction experiments was established. It was shown that the intensive fluctuations of environmental conditions are very important for the survival of living forms introduced into subarctic regions.