Response
of Soil-Associated Microbial Communities
to Intrusion of Coal Mine-Derived Acid Mine Drainage
- Publication date
- Publisher
Abstract
A system
has been identified in which coal mine-derived acid mine
drainage (AMD) flows as a 0.5-cm-deep sheet over the terrestrial surface.
This flow regime enhances the activities of Fe(II) oxidizing bacteria,
which catalyze the oxidative precipitation of Fe from AMD. These activities
give rise to Fe(III) (hydr)oxide-rich deposits (referred to as an
iron mound) overlying formerly pristine soil. This iron mound has
developed with no human intervention, indicating that microbiological
activities associated with iron mounds may be exploited as an inexpensive
and sustainable approach to remove Fe(II) from AMD. To evaluate the
changes in microbial activities and communities that occur when AMD
infiltrates initially pristine soil, we incubated AMD-unimpacted soil
with site AMD. Continuous exposure of soil to AMD induced progressively
greater rates of Fe(II) biooxidation. The development of Fe(II) oxidizing
activities was enhanced by inoculation of soil with microorganisms
associated with mature iron mound sediment. Evaluation of pyrosequencing-derived
16S rRNA gene sequences recovered from incubations revealed the development
of microbial community characteristics that were similar to those
of the mature iron mound sediment. Our results indicate that upon
mixing of AMD with pristine soil, microbial communities develop that
mediate rapid oxidative precipitation of Fe from AMD