Change in carbon dioxide fluxes along a elevation/precipitation gradient in a dryland watershed.
This project takes advantage of 2 years of high frequency soil profile respiration data paired with continuous measures of soil moisture, soil temperature, and local meteorological information located at the Reynolds Creek Experimental Watershed-Critical Zone Observatory in southwestern Idaho. One goal of the project is to assess pedon-scale controls on soil respiration rates. The ultimate goal is to pair our findings with broad-scale (eddy flux) carbon flux data collected simultaneously at the same sites to refine estimates of ecosystem carbon exchange and address issues of scaling.
Interactions between soil hydrological and biogeochemical processes in the context of changing hydroclimate and land cover.
Utilizing unique long-term (+20 yr) experimental plots associated with the Idaho National Laboratory DOI-NERP site, I demonstrate dryland ecosystems may be less susceptible to long-term shifts in hydroclimate and more vulnerable to variability in year-to-year seasonal precipitation and thus antecedent soil moisture. In addition, variation in soil depth and vegetation cover interact with short-term precipitation patterns, altering soil water storage capacity and temporal patterns in nutrient cycling.
Soil depth and precipitation seasonality also modify the ratio of soil inorganic to organic carbon storage.
In the Sagebrush Steppe, this results in greater inorganic carbon in treatments receiving increased summer precipitation and with shallow soils. Although inorganic carbon increases the residence time of soil carbon, organic carbon provides many ecosystem services essential to ecosystem function that may be marginalized with changing climate.
