Heterogeneity of Microbial Community Dynamics in Incipient Soils.

Soil microorganisms are critical drivers of biogeochemical processes. These microbes, in conjunction with their physical and chemical environment, contribute to ecosystem functioning and services of the landscape, have a profound impact on soil formation, and are of particular importance in marginal lands characterized by low biotic diversity. We examined a soil lysimeter filled with incipient basal material to examine how microbial communities assemble themselves in incipient systems and at what scale of study do these assemblies occur. The key questions asked were: 1) what is the spatial heterogeneity of microbes over a new and evolving landscape with inherent oligotrophic conditions, 2) can patterns in diversity translate to patterns in microbe-mediated weathering processes and soil formation, and 3) how do microbes turn over carbon in the face carbon-poor environment. I hypothesized that stratification of environmental conditions, brought about by varying water potential, flow paths, and redox conditions, will drive the heterogeneity of microbial life in a sub-meter scale and that this heterogeneity will be observed across community structure, function, assembly, and carbon metabolism. Phylogenetic gene amplification approach, Null Model testing, and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry revealed heterogeneity zones at different scales of inquiry. The goal is to use these types of microbe-environment relations to predict strategies undertaken by microbes to survive and influence marginal landscapes.