To address the combined effects of cadmium (Cd) and elevated CO2 on soil microbial communities, DGGE (denaturing gradient gel electrophoresis) profiles, respiration, carbon (C) and nitrogen (N) concentrations, loessial soils were exposed to four levels of Cd, i.e., 0 (Cd0), 1.5 (Cd1.5), 3.0 (Cd3.0) and 6.0 (Cd6.0) mg Cd kg(-1) soil, and two levels of CO2, i.e., 360 (aCO2) and 480 (eCO2) ppm. Co...

The large-scale release of wild-type or genetically modified bacteria into the environment for control of plant diseases or for bioremediation entails the potential risk of groundwater contamination by these microorganisms. For a model study on patterns of vertical transport of bacteria under field conditions, the biocontrol strain Pseudomonas fluorescens CHA0, marked with a spontaneous resista...

[1] Sulfate, nitrate, and chloride are major water-soluble anions in soils of the McMurdo Dry Valleys (MDV), Antarctica. We measured the chloride stable isotope composition of 40 soil samples from 16 different soil profiles. The soil profiles come from three different microclimate zones in the MDV: a coastal thaw zone, which fosters a seasonally saturated active layer; a stable upland zone, in ...

The movement of unconsolidated materials near the Earth’s surface is often driven by disturbances that occur at a range of spatial and temporal scales. The nature of these disturbances ranges from highly variable, such as tree turnover, to periodic and predictable, such as frost heave or creep. To explore the effect of probabilistic disturbances on surface processes, we formulated a granular cr...

A multi-layer one-dimensional vertical model of the upper soil, vegetation and lower atmosphere is developed and implemented. This model includes explicit representations of the heat and moisture diffusion both in the soil and in the atmosphere, and computations of various mass and energy fluxes at the soil-air, vegetation-air and soil-root interfaces. Four models are run in parallel to compute...

This paper presents model simulation results of vapor intrusion into structures built atop sites contaminated with volatile or semi-volatile chemicals of concern. A three-dimensional finite element model was used to investigate the importance of factors that could influence vapor intrusion when the site is characterized by non-homogeneous soils. Model simulations were performed to examine how s...

Soil microbes are highly diverse and control most soil biogeochemical reactions. We examined how microbial functional genes and biogeochemical pools responded to the altered chemical inputs accompanying land use change. We examined paired native grasslands and adjacent Eucalyptus plantations (previously grassland) in Uruguay, a region that lacked forests before European settlement. Along with m...