Collaborative Research: Linking Microbial Communities and Iron Geochemistry to Improve Acid Mine Drainage Bioremediation

Abandoned mines release very acidic water called acid mine drainage (AMD) that is rich in metals like iron, copper, aluminum, and arsenic. Bioremediation – using life, especially bacteria to remove metals and other toxins from AMD streams is more cost effective than other active treatment methods. In AMD bioremediation, bacteria take iron dissolved in water and turn it into rust.

The rust then scrubs other heavy metals from the system. The success of bioremediation relies on how quickly and effectively these organisms can remove iron as rust. However, we don’t know what species remove iron the fastest or how or if iron is redissolved once it is buried.

The overarching goal of this research is to unravel what controls the rate at which iron is removed, whether processes in the subsurface can undercut these processes by re-dissolving iron, and whether we can generate an environmental “probiotic” to increase iron removal in AMD sites.

We do not know the species or the geochemical conditions that promote rapid Fe(II) oxidation. Therefore, the researchers will systematically link geochemistry and microbial metabolic potential to iron oxidation rate. Iron reduction in subsurface environments can undermine bioremediation efforts but little is known about biogeochemistry in the AMD subsurface.

Therefore, the researchers will use porewater geochemistry and microbial communities to examine the biogeochemical processes occurring in the AMD subsurface. Seeding microbial communities is a promising strategy for enhancing bioremediation efficacy. However, these efforts can by stymied by complex interactions between geochemistry, ecology, and dispersal.

Therefore, the researchers will perform a field scale AMD seeding experiment using constructed AMD ecosystems to determine if seeding is feasible. The researchers will also make significant contributions to undergraduate science education by developing a course-based undergraduate research experience, a data-rich module for undergraduate courses and offering a summer research opportunity for undergraduate students.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.