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1

Features of the blood biochemical composition and adsorption-transport function of erythrocytes in the grey seal (Halichoerus grypus Fabricius, 1791) in the early postnatal period of development

Автор: Erokhina

The results of the study of certain biochemical parameters of blood in grey seals (Halichoerus grypus Fabricius, 1791) from birth to weaning are presented. In the blood plasma, 20 indices describing the state of the metabolism of proteins, carbohydrates, lipids, minerals (total protein, urea, creatinine, glucose, lactic acid, total lipids, triglycerides, cholesterol, calcium, phosphorus, sodium, potassium, magnesium, iron, aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase, creatine kinase, alkaline phosphatase, lactate dehydrogenase) are studied. It has been established that metabolic changes in the early period of postnatal development of grey seals occur in mammals in general, but the expression level of individual reactions may be considered a feature of pinnipeds. By the ratio of transaminase activity, the predominance of catabolism over anabolism was established in animals in the studied period of development. The most significant changes in the metabolism of grey seals were noted during weaning and the transition to self-feeding. The adsorption- transport function of erythrocytes was evaluated by washout on the erythrocyte membranes using 3% sodium chloride solution. It was established that all detected components of blood plasma are found in erythrocyte washings. The level of adsorption, expressed as a percentage of the content of a certain metabolite in the blood plasma, is not the same for different compounds. Enzymes, urea, creatinine, lipids are adsorbed most on the erythrocyte membranes (in some cases more than 100%), and glucose, lactic acid, cholesterol, iron, calcium are adsorbed in a smaller quantity (<50%). The data obtained indicate that the transfer of organic compounds on erythrocytes is more variable and demonstrative than shifts in the corresponding blood plasma parameters, and erythrocytes can participate in maintaining a range of concentrations of a number of substances in the blood plasma.

2

Features of winter zooplankton assemblage in the central trough of the Barents Sea

Автор: Dvoretsky

The Barents Sea is a highly productive shelf region. Zooplankton assemblages are a key component of the carbon cycle in Arctic marine ecosystems; they transfer energy from lower trophic levels to higher levels, including larval and young commercial fish. The winter state of the zooplankton community in the Central Through and their slopes (Barents Sea) was investigated in late November 2010. Vertical structure of water layer was characterised by pycnocline located below 80 m. The upper strata were occupied by transformed Atlantic Water, while winter Barents Sea Water with negative temperatures was in the bottom strata. Total zooplankton abundance varied from 162 to 1214 individuals/m3. Biomass ranged from 88 to 799 mg wet mass/m3. Copepods dominated in terms of total zooplankton abundance (average 99%) and biomass (92%). Maximum densities of Calanus finmarchicus and Calanus glacialis were registered in the frontal zone separating warm and cold water masses. Abundances of Metridia longa and O. similis were highest in cold waters. Three groups of stations differing in terms of the common copepod composition were delineated with cluster analysis. The age structure of Calanus finmarchicus and Metridia longa was characterised by a prevalence of copepodites IV–V. Total zooplankton abundance and biomass were correlated to water temperature and salinity, suggesting that hydrological conditions were the key driver of spatial variations of the zooplankton communities. High biomass of large copepods suggests potential significance of the investigated region for feeding of young and adult fish.