Microbial communities provide many critical ecosystem functions to soils, including organic matter decomposition and nutrient cycling. Microorganisms use a variety of metabolic processes to break down complex macromolecules into more labile constituents such as sugars, amino acids and organic acids in soils. These soils also present complex environments with gradients in bulk soil properties and chemistry. The goal of this research is to evaluate the importance of edaphic factors on microbial community structure and function at the Wild Basin Wilderness Preserve in Austin, TX. In order to test our hypothesis that microbial community composition will be structured and function due to edaphic factors we collected triplicate soil samples at 17 sites May 2016 through June 2017. Bulk soil characteristics and chemistry were measured as well as molecular identification of microbial communities using the 16s rRNA gene sequence. Community function was measured through carbon substrate utilization of 32 different carbon compounds with Biolog EcoPlates.
Results/Conclusions
At the phyla level four major groups of microorganisms were identified while the overall community composition was composed of mostly of low abundance rare taxa. Great variation in the range of carbon substrates utilized by communities were measured while polymers were preferentially metabolized by the majority of sites sampled. A general stochastic pattern was seen in both the community assembly and function with the exception of a few individual taxa displaying deterministic relationships to pH, soil moisture, and soil organic carbon.