PARENT SESSION
Oral Session #67: Ecotoxicology and Applied Ecology.
Presiding: W. Snyder
Wednesday, August 7. 1:00 PM to 4:45 PM. Cochise Meeting Room, TCC.
Plant-bacterial-fungal interations in remediation of terrestrial oil spills.
VAVREK, MILAN*,1, COLGAN, WES1, CAMPBELL, WILLIAM1, 1 Louisiana Tech University, Ruston, LA
ABSTRACT- Facilitating growth and metabolism of bacteria, fungi and plants may accelerate degradation of spilled oil in terrestrial systems. These organisms potentially improve each other′s performance and act on oil directly. The importance of the interaction was assessed. Additionally, the benefits of using a mixed culture of plant species relative to monoculture were determined. One hundred-75 L microcosms consisting of totally or selectively sterilized oak-hickory-pine soils (n = 10) were used in a full factorial design with plants, bacteria and fungi as main effects. Treatments also included 0 or 6 L m-2 of crude oil. The extent of remediation was determined by quantifying residual oil, and plant and ectomycorrhizal fungi performance. After 32 weeks, interactions appeared to be antagonistic as reduction in total petroleum hydrocarbons ranged from 73.6% in microcosms with bacteria only (69.8% with fungi only) to 25.6% with plants and bacteria (0.18% with plants and fungi). Bacteria also reduced plant shoot and fruit biomass, and root area. Competition for limiting resources may account for these negative interactions. Percent of feeder roots colonized by ectomycorrhizal fungi was not affected by the presence of bacteria and did not differ from controls. The mixed culture of plant species improved plant performance, but did not affect oil degradation rates. Thus, restoration may require monitoring of soil nutrients, repeated applications of fertilizer and consideration of interactions among biological components.
KEY WORDS: bioremediation, oil spills, revegetation, interactions