Microbial Biodegradation of Crude Oil and Corexit 9500 in the Arctic Ocean

Scope of Work:

As we continue to understand the fate of oil in Arctic environments it is important to understand the rate and extent of oil biodegradation, how the microbial community responds to oil and the potential for oil degradation in different locations in the water column. The potential for chemical dispersants to biodegrade in the Arctic should also be assessed as oil spill responders consider appropriate response options. Surface seawater was collected from the Hanna Shoal study area in the Chukchi Sea in the fall of 2013 (September –October). Mesocosms were incubated over a time course for up to 28 days and contained freshly collected seawater, a small nutrient addition, and either Alaska North Slope (ANS) crude oil or Corexit 9500. Chemical analyses of these incubations can provide information on the rate and extent of oil biodegradation in offshore surface water as well as determine the fate of the various components of Corexit 9500. Additional incubations were also performed to determine the effects of oil and Corexit 9500 on the microbial community by identifying active oil/dispersant degrading microbes and the presence of petroleum degrading and nutrient cycling genes. This proposal would allow the analysis of these samples. Petroleum losses will be quantified using gas chromatography / mass spectrometry (GC/MS) analysis while dispersant losses will be quantified using liquid chromatography (LC). High throughput sequencing of bacterial 16S rRNA genes will be conducted on filtered seawater samples to provide information regarding the taxonomic identity of the microbial communities and GeoChip microarrays will be used to detect functional genes. This proposal will provide insight into how this important region of the Arctic Ocean would respond to inputs of petroleum and dispersant and how it compares to another well-studied cold water system