Petroleum hydrocarbon degrading microbial communities of Arctic Ocean sediment

Abstract

Offshore oil development in Arctic Alaska is expanding. Since biodegradation is a major removal mechanism of petroleum hydrocarbons from the environment, baseline data on microorganisms present are important. I estimated microbial populations and their degradation activities in Arctic Ocean sediments, and examined how sediment affects phenanthrene bioavalability. Populations of hydrocarbon degraders were significantly higher in sediments from near Prudhoe Bay than near Barrow. However, microbial counts from Prudhoe Bay were similar to those measured in the 1970s suggesting that the difference was not due to oil development activities. Total microbial counts were higher than in more temperate regions. All sediments had low hexadecane and phenanthrene mineralization potentials. The apparent partition coefficient, Kp, for phenanthrene in sediment/seawater slurries generally increased with increasing sediment organic carbon. But without aging, sediment did not influence the mineralization of phenanthrene. Overall, biodegradation will likely be a slow removal mechanism of contaminants from the Arctic marine environment.