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This work investigates how peatlands can be used as archives of past environmental conditions to record changes in atmospheric deposition of some (especially lithophile and chalcophile) elements and any water–rock–organic matter interactions followed by the sedimentation or leaching of others. We have provided a detailed description of both the distribution of various groups of elements and their chemical species in the entire depth of peat deposits. The study analyzes the features of the peat sediment formation and element distribution in the 0–310 cm depth core sample of peat deposits of the Ubinskoye peat bog located in the forest-steppe zone of Western Siberia. The study reveals a profound diagenetic transformation of water and peat chemical composition. Element speciation investigated using the modified Tessier sequential extraction procedure showed the vertical transition of an oxidative geochemical environment to a reducing one with the formation of geochemical barriers for variably valent elements. Computer modeling calculations of saturation indices of pore solutions in relation to a number of minerals allowed us to estimate the degree of equilibrium of the system and the direction of its transformation. Early diagenetic processes lead to the deposition of authigenic minerals. Therefore, barite forms on the redox line, while pyrite is found in the reducing environment. With depth, the content of Ca, Mg and Sr increases, which leads to the formation of authigenic carbonates. [ABSTRACT FROM AUTHOR]

Background concentrations of main trace elements and polycyclic aromatic hydrocarbons (PAHs) were investigated in pristine soils of the Beliy Island situated in the Kara Sea, Yamal autonomous region, North-West Siberia, Russia. Belyi Island is considered as reference landscpae for further investigation of soil polychemical contamination of the Yamal region. Three plots with different functional load (mature ecosystem, occasionally and permanently affected plots) were investigated with aim to evaluate the trend of long term polychemical effect on Stagnic Cryosols – benchmark soil type of the Yamal region. Accumulation of trace elements was not fixed in all soils investigated due to absence of direct sources of heavy metals on the territory of the Beliy Island. At the same time, there were essential alterations of PAHs fractional composition and content due to pronounced accumulation of the petroleum products combustion in the vicinity of the permanent meteorological station and former seasonal field base. The most intensive and statistically significant accumulation was noted for phenanthrene, anthracene, benzo[k]fluoranthene and benzo[a]pyrene. This indicates accumulation of the PAHs in soils, affected by the anthropogenic activity on the meteorological station. The most pronounced differences were revealed for the superficial layer of 0–5 cm. Deeper horizons of soil did not show accumulation of contaminants. Data obtained can be used for organization of further monitoring of contamination of soils and landscapes in Yamal as developing and industrial region.

Fire shapes the world's terrestrial ecosystems and has been influencing biodiversity patterns for millennia. Anthropogenic drivers alter fire regimes. Wildfires can amplify changes in the structure, biodiversity and functioning of the fast‐warming tundra ecosystem. However, there is little evidence available, how these fires affect species diversity and community composition of tundra ecosystems over the long term. We studied long‐term fire effects on community composition and diversity at different trophic levels of the food web in the subarctic tundra of Western Siberia. In a space‐for‐time approach we compared three large fire scars (>44, 28 and 12 years old) to unburnt controls. We found that diversity (measured as species richness, Shannon index and evenness) of vascular and non‐vascular plants and birds was strongly affected by fire, with the greatest species richness of plants and birds for the intermediate‐age fire scar (28 years). Species composition of plants and birds still differed from that of the control >44 years after fire. Increased deciduous shrub cover was related to species richness of all plants in a hump‐shaped manner. The proportion of southern (taiga) bird species was highest in the oldest fire scar, which had the highest shrub cover. We conclude that tundra fires have long‐term legacies with regard to species diversity and community composition. They may also increase landscape‐scale species richness and facilitate range expansions of more southerly distributed species to the subarctic tundra ecosystem. [ABSTRACT FROM AUTHOR]

Fires are predicted to increase in Arctic regions due to ongoing climate change. Tundra fires can alter carbon and nutrient cycling and release a substantial amount of greenhouse gases with global consequences. Yet, the long-term effects of tundra fires on carbon (C) and nitrogen (N) stocks and cycling are still unclear. Here we used a space-for-time approach to investigate the long-term fire effects on C and N stocks and cycling in soil and aboveground living biomass. We collected data from three large fire scars (>44, 28 and 12 years old) and corresponding control areas and used linear mixed-effects models in a Bayesian framework to analyse how the stocks and cycling were influenced by fire. We found that tundra fires did not affect total C and N stocks because a major part of the stocks was located belowground in soils, which were largely unaltered by fire. However, fire had a strong effect on stocks in the aboveground vegetation, mainly due to the reduction of the lichen layer. Fire reduced N concentrations in graminoids and herbs on the younger fire scars, which affected respective C/N ratios and indicated an increased post-fire competition between vascular plants. Aboveground plant biomass was depleted in 13C in all three fire scars. This could be related to a lower 13C abundance in CO[sub 2] in the ambient air because of increased post-fire decomposition, providing a source of 13C-depleted CO[sub 2]. In soil, the relative abundance of 13C changed with time after fire because of the combined effects of microbial decomposition and plant-related fractionation processes. Our results indicate that in lichen-rich subarctic tundra ecosystems, the contribution of fires to the release of additional carbon to the atmosphere might be relatively small as soil stocks appear to be resilient. [ABSTRACT FROM AUTHOR]