World Congress of Soil Science Logo 18th World Congress of Soil Science
July 9-15, 2006 - Philadelphia, Pennsylvania, USA
International Union of Soil Sciences

Monday, 10 July 2006 - Friday, 14 July 2006

This presentation is part of 158: 3.5C Combating Global Soil & Land Degradation III. Agro- and Forest Ecosystems: Physical, Chemical and Biological Processes - Poster

Enhancing Petroleum Hydrocarbon Biodegradation Efficiency by Indigenous Microbial Consortia in Semi-Arid Australian Soils.

Suman J. George, Mark Tibbett, Alyssa Barron, and Alexis Davie. Centre for Land Rehabilitation, School of Earth and Geographical Sciences, Univ of Western Australia, 35 Stirling Highway, WA 6009, Crawley, Australia

Petroleum products are one of the most widely used chemicals in society today, which also contains hazardous chemicals therefore possess constant threat of oil spills to onshore and offshore environment. The use of microbes to clean up polluted environments-–bioremediation-–is a promising approach to improve environmental conditions but is hindered by limited understanding of the process. To ensure optimal petroleum hydrocarbon degradation, environmental conditions specific to each site need to be determined. The common limitations to effective bioremediation in semi-arid, Barrow Island soils of Western Australia seem to be the lack of soil moisture and nutrients. The biodegradation of petroleum hydrocarbon in incubated soil was determined from microbial basal respiration (CO2 evolution), microbial biomass, substrate induced respiration, and petroleum hydrocarbon breakdown. Maximum microbial respiration was observed at oil levels of 50 and 75 g kg-1. Microbial biomass carbon was generally higher at lower oil concentrations and steadily declined at higher oil concentrations. The degradation of saturated hydrocarbon molecule chains was also generally greater at low oil concentrations (5 and 10g kg-1) than at high concentrations (50 and 100g kg-1). Soil respiration was maximum within the ranges of 50 and 70% moisture saturation. Reducing oil spill concentrations by tilling and increasing the soil moisture content will encourage optimal bioremediation of oil contaminated soils on Barrow Island. Only the lowest rate of nitrogen application (100 mg kg-1 N) was found to be significantly beneficial to the degradation of petroleum hydrocarbon. Microbial respiration was significantly enhanced with the addition of phosphorus (400, 200 and 100 mg kg-1 P). A combined N and P treatment was not only superior in encouraging microbial respiration but its effect also exceeded the sum of the individual N and P treatments.

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