Defense Date


Graduation Date

Fall 12-18-2020


One-year Embargo

Submission Type


Degree Name



Biological Sciences


Bayer School of Natural and Environmental Sciences

Committee Chair

Nancy J. Trun

Committee Member

John F. Stolz

Committee Member

Brady A. Porter

Committee Member

Chris W. Marshall


abandoned mine drainage, AMD, bioremediation, passive remediation systems, sulfate-reducing bacteria, sulfur-oxidizing bacteria, iron-oxidizing bacteria, sulfur cycling, iron cycling


Abandoned mine drainage (AMD) has resulted in worldwide devastation. Passive remediation systems (PRS) are a cost-effective option to treat AMD. While the geochemistry (abiotic) of these systems is well understood, little work has been done to characterize the microbial communities (biotic) that naturally form within these systems. The goal of this dissertation was to identify the effects that bacterial communities have on the efficiency of PRSs. Four passive remediation sites built to treat coal mine drainage were studied: two that treat acidic discharges (Boyce and Middle Branch) and two that treat circumneutral discharges (Wingfield Pines and Lowber). Survey studies suggested a biotic influence, not only in its potential for bioremediation, but also as a possible cause of remobilization of heavy metals such as iron, manganese, and aluminum. The survey studies also revealed that while PRSs have shown great success at removing metal contamination, sulfate removal was eluded in circumneutral systems. Further exploration revealed that the sulfate-reducing bacteria were not only present, but when supplemented with a viable carbon source were metabolically capable of sulfate reduction. Additionally, this work identified symbiotic relationships between bacterial partners, Serratia marcescens strain MV493 and Sphingomonas LK11 strain MV492, that couple nitrate reduction with iron oxidation. Collectively, these findings support a need for a greater understanding of the biotic influences acting on PRSs. The results presented herein provides insights into the bacterial communities present in PRSs, tests their metabolic capabilities, and reports findings that can be advantageous to PRS efficiency and longevity.



Additional Citations

Valkanas, Michelle M., and Nancy J. Trun. "A seasonal study of a passive abandoned coalmine drainage remediation system reveals three distinct zones of contaminant levels and microbial communities." MicrobiologyOpen 7.4 (2018): e00585.

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