Contributions of Soil Communities to Ecosystem Respiration and Greenhouse Gas Emissions
Phase 1 of my proposed project will be to examine the relationships between soil temperature and RES as well as soil water content and RES. I am proposing to assess the above relationships because current, published estimates are that RS is approximately ½ of RES, thus, using RES to estimate RS will be a reasonable way to estimate RS based on data collected in 2008 – 2010 (Chen et al. 2010). These data and results will be helpful, when combined with additions results from other soil analyses, in determining how gradients of TS and SWC affect nightly RS and total yearly CO2 release, in tons, on a year-to-year basis. These site specific RS results will also help begin establishing whether the soils at each specific site, are contributing to that site becoming a carbon source or a carbon sink. Initiation of my studies and experiments with the tower sites will start with analyzing the already collected data for correlations between TS and SWC, with RES. These data analyses are straightforward, thus they should take approximately 3 – 4 weeks. I expect to be able to start analyzing these tower data in mid-May, after finals. My analyses of these tower collected data should be complete by early – mid June.
For phase 2, I will gather soil samples, in June, using a spatial pattern, e.g. sampling with a hub and spoke design with a plant being at the center (focal plant) and transects radiating out, in order to better estimate how changes in soil temperatures, soil water contents, plant species identities, and plant status, e.g. live or dead, all affect soil CO2 (RS) and N2O emissions. For this part of my study, I will take digital photos of each tower site, which I will use to identify potential transects that I can establish between focal plants. Further, from these soil samples, I will analyze sub-samples for soil extra cellular enzyme activity (EEA), soil microbial biomass, hyphal lengths, as well as quantifying soil pH and soil nutrient availabilities. Finally, I will assess plant root colonization of the dominant plants in each biome by checking the roots for colonization by ectomycorrhizal fungi, Arbuscular Mycorrhizal fungi, and dark septate endophytes.