The Effects of Forest Management Practices on the Community Structure of Chemolithotrophic Bacteria in the Bankhead National Forest.

The effects of forest management practices on soil microbial diversity are currently being studied in the Bankhead National Forest (BNF) in Franklin and Winston Counties, Alabama. In addition to affecting the natural carbon (C) cycle and destroying C stored in organic plant material on the forest surface, forest fires and thinning affects soil physical and chemical characteristics which influence soil C mineralization and CO₂ emissions processes. It is, therefore, important to study how forest management practices in BNF affect soil C mineralization, CO₂ emission and C sequestration and their potential impact on global climate change. Since C is central to global climate change, this study observed chemolithotrophic bacteria, which obtain their energy from the oxidation of chemical compounds and fixed CO₂ for cell biosynthesis. The aim of this research was to identify the red-like ribulose-1, 5-bisphophate carboxylase/oxygenase (RubisCO) large subunit coding genes in soils from the BNF that have undergone management through thinning and prescribed burning. We hypothesized that chemolithotrophic bacteria will be more prevalent in samples that have been burned and thinned than those that have only been thinned. cbbL gene fragments were amplified from extracted soil DNA using PCR. Products were cloned, sequenced and analyzed phylogenetically. Soils were also analyzed for microbial activity using microbial biomass carbon.  Microbial biomass carbon determined there was no significant difference between treatments. The majority of environmental red-like cbbL genes were only distantly related to already known cbbL sequences and even formed separate clusters.