Date of Graduation
Davis College of Agriculture, Natural Resources and Design
Division of Plant and Soil Sciences
Zachary B. Freedman
Ember M. Morrissey
Ember M. Morrissey
Jeffrey G. Skousen
Understanding the successional dynamics governing soil microbial community assembly is a promising way to advance development of remediation strategies for lands disturbed by anthropogenic activities. The environmental and ecological influences shaping these communities following soil disturbance remain only partially understood. One example of a physical anthropogenic disturbance is extraction of minerals such as coal by surface mining. Surface mining removes natural soils and these soils may be replaced immediately on adjacent reclaimed areas or they may be stored in piles for later use. During reclamation, the soil is replaced on the landscape and the site is re-vegetated with grasses and trees. Throughout this process, the soil’s physical and chemical properties are drastically changed and soil microbial communities are spatially displaced, causing changes in water relations and nutrient cycling, as well as microbial abundance and community composition. These changes have a large effect in eliciting selective pressure on microbial taxa (i.e., deterministic processes). Dispersal and ecological drift are also important in shaping communities following disturbance (i.e., stochastic processes). We investigated the influence of stochastic and deterministic factors in shaping the soil microbiome following reclamation using formerly surface mined and reclaimed areas ranging from 2 to 32 years since reclamation occurred. A suite of soil chemical and physical parameters were measured to quantify the influence of deterministic processes and time was considered a proxy for stochastic processes. Sequencing of bacterial and fungal rRNA gene amplicons coupled with a linear modeling approach revealed that the soil microbiome following mine reclamation is shaped by both deterministic and stochastic influences, but that deterministic factors influence microbial succession more than stochastic factors by a ~4-fold difference. Further, while microbial biomass and diversity did not consistently increase with time following reclamation, the abundance of ecologically important bacterial taxa (e.g., Alpha- and Deltaproteobacteria) showed varying but significant responses, potentially due to the concomitant increases in soil nutrients such as carbon, nitrogen, and phosphorous. Our results suggest that management of deterministic soil characteristics over a sufficient time period could result in an accelerated recovery of the soil microbiome to pre-disturbance levels and composition, and therefore increased productivity of post-mining land uses.
Kane, Jennifer Lynne, "Soil microbial succession following surface mining is governed primarily by deterministic factors" (2019). Graduate Theses, Dissertations, and Problem Reports. 3922.