Tuesday, June 5, 2007 - 8:45 AM
89

Effects of acid mine drainage on biofilm extracellular enzyme activity in streams

Steven T. Rier1, Jennifer C. Biddinger1, Matthew E. McTammany2, Thomas L. Bott3, and Bernard W. Sweeney3. (1) Department of Biological and Allied Health Sciences, Bloomsburg University, 400 East Second Street, Bloomsburg, PA 17815, (2) Biology Deparment, Bucknell University, Lewisburg, PA 17837, (3) Stroud Water Research Center, 970 Spencer Road, Avondale, PA 19311

Acid mine drainage (AMD) from abandoned coal mines is a widespread impairment to streams in the mid-Atlantic region of the United States. This study examined the effects of AMD on extracellualar enzymes utilized by microorganisms inhabiting stream biofilms to cleave large organic compounds and mineralize organic phosphorus and nitrogen.  Six extracellular enzyme activities and microbial biomass were measured on artificial substrata placed in an AMD-impacted stream, an AMD-remediated stream, and an unimpacted control stream one month prior to sampling.  Phosphatase activity was five times higher in the AMD-impacted stream while leucine-aminopeptidase was less than a third of that observed in the other streams.  These results suggest that the AMD-impacted stream was extremely phosphorus limited, which may be due to phosphates complexing with heavy metals in AMD.  Phenol oxidase and peroxidase activities in the AMD-impacted stream were considerably lower compared to the other streams.  These enzymes are integral to the degradation of polyphenolic compounds, thus a substantial portion of the DOM pool may not be accessible to biofilm microorganisms in AMD-impacted streams.  Overall, these results suggest that low pH and heavy metals associated with AMD influence microbial dynamics in streams and that remediation may restore these critical ecosystem functions.


Web Page: facstaff.bloomu.edu/srier/

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