Date of Award
Summer 8-4-2022
Degree Type
Thesis
Degree Name
Master of Science in Integrative Biology (MSIB)
Department
Biology
Committee Chair/First Advisor
Mario Bretfeld
Major Professor
Thomas C. McElroy
Second Committee Member
Matthew Weand
Third Committee Member
Ramya Rajagopalan
Abstract
Heavy metals pose serious threats to organisms due to their mobility and solubility in soil. Bacteria communities are vulnerable to heavy metal stress, but the response of different bacterial groups may vary depending on the level and type of heavy metal contamination. When subjected to heavy metal stress, many bacterial species or populations may become extirpated, while some may survive to form the foundations of a new microbial community. A study of the bacterial community at a lead (Pb) contaminated study site in Cedartown, GA, found that the microbiome in the Pb contaminated soil had significantly lower species richness. But the soil had significantly greater diversity at the phylum and class taxonomic levels than non-contaminated reference sites. Similarly, the bacterial community structure differed from the reference (low Pb) sites. To Investigate the influence of land coverage and soil chemical factors on bacterial diversity and community structure around the Pb-contaminated site in Cedartown, GA, we (1) used Next Generation Sequencing (NGS) to survey soil bacterial diversity, (2) predicted that land cover, soil composition, and spatial distance between sampled locations would be important predictors of bacterial community structure, and (3) predicted that soil heavy metal concentrations would affect soil bacterial diversity and structure. We found insignificant levels of Pb outside the contaminated site. The soil bacterial community structure was relatively homogeneous at the phylum and class levels despite differences in land coverage and soil chemical composition. Distance between sample sites explained some phylum level variation in the observed bacterial community structure. In comparison, soil chemical composition explained some class-level variations in the observed bacterial communities.