Vol 10, No 2 (2017)

Results of long-term estimates of carbon stock and current carbon sequestration in pine–shrub–sphagnum BGC in Vasyugan Mire (VM) are discussed. In different climatic conditions (different years), NРP varies from 206 to 337 g Cm^–2 year^–1. An increase in carbon-emission intensity was detected in drier vegetation periods. Most of the carbon losses are the emission of carbon dioxide (average is 61.3 g Cm^–2 years^–1, or 23.5% NPP). It is possible to ascertain the progression of peat formation. The removal of the carbon by bog waters was calculated using a mathematical model. It was estimated as 3.0% NРР with a mean value of the removal of 7.9 g Cm^–2 years^–1. Based on the model of bogs vertical growth, the modern rate of carbon accumulation was estimated in the range from 10.3 g Cm^–2 years^–1 in polygonal bogs to 51.7 g Cm^–2 years^–1 in grassy bogs.

This paper presents the results of studying the relationship of the hydrothermal conditions (air temperature and precipitation) and the ecological spectrum of the flora of vascular plants in the Tom River Basin. Based on the calculated coefficients of linear correlation of the average monthly data on temperature and precipitation with the ecological groups of model basins, it is found that the influence of the main parameters of the hydrothermal regime (temperature and precipitation) in the plains and in the mountains affects the ecological spectrum of the flora to varying degrees. The greatest impact on the properties of the ecological spectrum is made by the hydrothermal conditions of the cold part of the annual cycle.

Changes in phytoplankton community composition typical for the increase in water trophic level had been noticed in 2009–2011 at the site of the open shallow of the Volga Reach in Rybinsk Reservoir (Volga), which is under the impact of grey heron colonies. The reduction in floristic abundance, the increase in the phytoplankton total biomass, and the increase in the proportion of phytophlagellates (cryptophytes, euglenales, dinophytes, and chrysophytes, as well as flagellar forms of green algae) were registered at the heronries. Changes in phytoplankton communities were temporary and were related to the heron nesting period; these allow us to consider the studied site a “traumatic” ecotone.

This study makes a multifactor analysis of the joint effect of reservoir contamination, parasitic infestation, and experimental hyperthermia on the activity of antioxidative enzymes (peroxidase, catalase, and glutathione S-transferase) in the pulmonate mollusk Lymnaea stagnalis from the clean Naroch Lake and contaminated Chizhovsky Reservoir in the Republic of Belarus. The activity of peroxidase is ascertained to be affected most strongly by the simultaneous effect of parasitic infestation and reservoir contamination and parasitic infestation coupled with experimental hyperthermia. The joint effect of parasitic infestation and reservoir pollution is found to influence the activity of catalase. Meanwhile, no correlation is found between the studied factors and the activity of glutathione S-transferase. It is shown that there is no mutual influence of the three studied factors on the activity of the investigated enzymes.

Biomarkers of oxidative stress such as catalase (CAT), glutathione S-transferase (GST), glutathione reductase (GR) activity, and malondialdehyde and reduced glutathione content, as well as heavy metal concentrations (HM: Pb, V, Cr, Mn, Co, Ni, Cu, Zn, and Cd), were studied in Dreissena polymorpha tissues. Mussels were collected on three sites located on the Rybinskoe Reservoir different in levels of anthropogenic pressure: the most polluted sites were 1 and 2 and site 3 was relatively clean. Mussels from sites 1 and 2 had higher concentrations of HM (Pb, V, Cr, Mn, Ni, Cu, and Mn) and their response to the pollutant action was manifested in increased processes of lipid peroxidation (LPO), the activation of CAT, and elevated level of GHS.

Four tree species in the Kostelec n. Č. l. arboretum (Czech Republic) have been repeatedly damaged by Dendrocopos medius. The unique aspect of this otherwise common behavior called girdling consists in regularly visiting the same trees every spring, although there are more than 1.200 tree species within the arboretum. We monitored transpiration, leaf phenology and the chemical composition of the xylem sap of girdled and nongirdled trees. Spectral analysis revealed slightly higher amounts of sugars, especially saccharose, in Cladrastis Raf. as the most regularly girdled tree among other conditions, comparing girdled to non-girdled trees. Higher transpiration rates were not confirmed in connection with girdling—quite the opposite—Cladrastis Raf. as the most highly favored tree for girdling showed the lowest transpiration rates (in average 6 kg water per day within spring months) compared to other non-girdled trees. We presume that the birds do not choose a particular tree on the basis of any visible or chemical traits but they examine many trees within their territory. Afterwards they probably remember the position of trees whose xylem sap starts to flow early in the spring compared to other trees, as their transpiration stream is enriched with sweet organic substances that represent an advantage for the forthcoming nesting period.