CHANGES IN MICROBIAL COMMUNITIES DURING
BIOREMEDIATION OF OIL AND BRINE SPILLS
Kathleen E. Duncan*
Bruce Roe
Fares Najar
University of Oklahoma
770 Van Vleet Oval
Norman, OK 73019
Voice: 405-325-4892
Fax: 405-325-3180
E-mail: kathleen.e.duncan-1@ou.edu
Greg Thoma
University of Arkansas
Fayetteville, AR
Chintan Mehta
Aditya Moralwar
Kerry L. Sublette
Laura P. Ford
University of Tulsa
Tulsa, OK
The Tallgrass Prairie Preserve (Nature Conservancy, located in Pawhuska, OK) has historically been the site of oil production. We have been conducting a multidisciplinary project on how to prevent spills of produced fluids and how best to remediate this highly biodiverse ecosystem. This presentation focuses on changes in the eubacterial soil community during bioremediation of two spills of produced fluids that occurred in 1999, one of dewatered crude oil alone, the other of oil plus brine. The emphasis is on identifying groups that are indicative of successful restoration. Dominant eubacteria at the sites were assessed by cloning and sequencing 16S rRNA which had been amplified from DNA extracted from soil samples collected from contaminated and uncontaminated control sites. Ammonium-oxidizing bacteria (AOB), which perform the first step in nitrification (oxidization of ammonium to nitrite), were detected by cloning and sequencing a portion of the gene coding for the first enzyme in the nitrification pathway, ammonium monooxygenase (amoA). Spills of crude oil and bioremediation procedures involving the addition of nitrogenous compounds to the spill site to enhance the rate of hydrocarbon removal are expected to affect the numbers and species composition of nitrogen-cycling bacteria. Disruption of nitrogen-cycling in turn affects the plant community, which is frequently nitrogen-limited.