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

Abiotic factors influence microbial diversity in permanently cold soil horizons of a maritime-associated Antarctic Dry Valley

The McMurdo Dry Valleys collectively comprise the most extensive ice-free region in Antarctica and are considered one of the coldest arid environments on Earth. In low-altitude maritime-associated valleys, mineral soil profiles show distinct horizontal structuring, with a surface arid zone overlying a moist and biologically active zone generated by seasonally melted permafrost. In this study, long-term microenvironmental monitoring data show that temperature and soil humidity regimes vary in the soil horizons of north- and south-facing slopes within the Miers Valley, a maritime valley in the McMurdo Dry Valleys. We found that soil bacterial communities varied from the north to the south. The microbial assemblages at the surface and shallow subsurface depths displayed higher metabolic activity and diversity compared to the permafrost soil interface. Multivariate analysis indicated that K, C, Ca and moisture influenced the distribution and structure of microbial populations. Furthermore, because of the large % RH gradient between the frozen subsurface and the soil surface we propose that water transported to the surface as water vapour is available to microbial populations, either as a result of condensation processes or by direct adsorption from the vapour phase.Francesca Stomeo, Thulani P. Makhalanyane, Angel Valverde, Stephen B. Pointing, Mark I. Stevens, Craig S. Cary, Marla I. Tuffin & Don A. Cowa