Analysis of carbon stocks and fluxes of urban lawn ecosystems in moscow megapolis

Urbanization results in irreversible transformations of vegetation and soils. Urban lawn is an important part of urban ecosystems, providing several principal ecological functions, including participation in global carbon cycle. Carbon stocks and fluxes in urban lawns are diverse due to the different functional uses (residential, recreational areas, etc.), and different morphogenetic and physico-chemical properties of soil and their components. The research was focused on C stocks and fluxes in urban lawns to assess their function in regulating atmospheric air composition. Soil CO2 emission and CH4 fluxes (summarized for summer period); soil organic C (SOC); below and aboveground biomass were studied. Carbon emission by soil respiration and C sequestration in biomass were considered to estimate C balance

Microbial communities and processes in Arctic permafrost environments

In polar regions, huge layers of frozen ground, termed permafrost, are formed. Permafrost covers more than 25 % of the land surface and significant parts of the coastal sea shelfs. Its habitats are controlled by extreme climate and terrain conditions. Particularly, the seasonal freezing and thawing in the upper active layer of permafrost leads to distinct gradients in temperature and geochemistry. Microorganisms in permafrost environments have to survive extremely cold temperatures, freeze-thaw cycles, desiccation and starvation under long-lasting background radiation over geological time scales. Although the biology of permafrost microorganisms remains relatively unexplored, recent findings show that microbial communities in this extreme environment are composed by members of all three domains of life (Archaea, Bacteria, Eukarya), with a total biomass comparable to temperate soil ecosystems. This chapter describes the environmental conditions of permafrost and reviews recent studies on microbial processes and diversity in permafrost-affected soils as well as the role and significance of microbial communities with respect to global biogeochemical cycles