Microbial Communities In Acid Mine Drainage Ecosystems
Open Access
- Author:
- Grettenberger, Christen Lynn
- Graduate Program:
- Ecology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- August 06, 2015
- Committee Members:
- Jennifer Macalady, Dissertation Advisor/Co-Advisor
Erica A H Smithwick, Committee Chair/Co-Chair
William D Burgos, Committee Member
Christopher Howard House, Committee Member - Keywords:
- microbial ecology
ecology
acid mine drainage
AMD
metagenomics
next-generation sequencing - Abstract:
- Microbial communities are important ecosystem engineers and they profoundly affect local and global biogeochemical cycling. For this reason, they can play important roles in bioremediation – we can harness their metabolic power to efficiently and inexpensively remediate environmental problems like acid mine drainage (AMD). Acid mine drainage is an industry-related pollution problem affecting watersheds globally. Current remediation strategies are often costly and ineffective. However, there has been recent interest in using bioremediation to treat AMD. This idea is based on the premise that naturally occurring iron(II)-oxidizing species can remove iron and other metals from AMD. To do so, it is necessary to understand microbial ecology in these ecosystems. This research aimed to discover the microbial factors that control the rate of iron-oxidation at a number of AMD sites and identify the ways in which these microbes alter biogeochemical cycling and may serve as valuable model systems in microbial ecology and bioremediation. Specifically, I aimed to (1) to identify the microbial species responsible for high iron-oxidation rates at Scalp Level Run, an AMD site where iron is removed five to seven times faster than other sites in PA and the Iberian Pyrite Belt, (2) to determine how microbial community composition and metabolic potential in subsurface microbial communities is influenced by subsurface geochemical gradients, and (3) to determine if geography may play a role in structuring microbial populations in AMD ecosystems. The microbial communities at Scalp Level contain a taxon closely related to Ferritrophicum radicicola, which is not found at other AMD sites. The presence of this taxa distinguishes Scalp Level from other sites, but the role it plays in biogeochemical cycling is unknown. At Brubaker Run, I found that, although community composition is different in surface than in subsurface microbial communities, their metabolic potential is not significantly different in the surface than the subsurface. Lastly, microbial communities in AMD may adhere to the distance-decay relationship. There is dispersal limitation between distant sites. This may indicate that for bioremediation to be successful, microbes may need to be transplanted from one site to another.