PBIO Colloquium | Functional Responses of Stream Communities to Acid Mine Drainage Remediation, March 11

The Environmental & Plant Biology Colloquium Series presents Mr. Sam Drerup on “Functional Responses of Stream Communities to Acid Mine Drainage Remediation” on Friday, March 11, at 11:50 a.m. in Porter Hall 104.

Drerup is a Ph.D. Candidate in Dr. Morgan Vis’ lab in the Environmental & Plant Biology Department at Ohio University

Sam Drerup, Ph.D. Candidate

Abstract: Acid mine drainage (AMD) is a global consequence of historical and present day mining activities. Remediation efforts have been successful in improving water quality with elevated pH and decreased dissolved metals. In many streams, there has been chemical and biological recovery. However, the goal of restoration is to improve both biological communities and processes within the stream. I compared biofilm community structure (using fatty acid profiles), function (primary production, extracellular enzyme activity), and food web structure from three stream categories; streams impaired by acid mine drainage, streams that have undergone remediation of AMD impairment, and streams that have not been impaired by AMD. Fatty acid profiles identified distinct communities associated with AMD-impaired streams or AMD-remediated and AMD-unimpaired streams and showed that these communities were not different throughout the sampling season. I found that the lowest rates of benthic biofilm productivity and primary producer biomass were in the impaired streams while AMD-unimpaired streams had the highest. Biofilm production and primary producer biomass in streams that were classified as remediated were in between impaired and unimpaired and not statistically different from either. Results of the extracellular enzyme analysis suggest that phosphorus availability is limiting production and biomass in the impaired and remediated streams, probably as a result of metal precipitates associated with AMD readily binding with biologically available forms of phosphorus. Isotopic analysis showed that two invertebrate predators (NIgronia sp. and Boyeria sp.) had lower reliance on autochthonous basal resources and that food web niche space was also reduced in remediated and impaired streams. The results of my dissertation suggest that although the water chemistry and taxonomic diversity in remediated streams has improved, function is still limited.   Benthic primary production is reduced, relative to the unimpaired streams, and food webs are still heavily dependent on detritus based carbon sources in remediated streams. In part, this reduction of benthic production and its importance to invertebrate food webs are due to phosphorus limitation.