oa DISTRIBUTION OF BACTERIOHOPANEPOLYOLS IN THE GULF OF MEXICO WATER COLUMN AFTER A DEEPWATER OIL SPILL

Methane (CH₄) is a potent greenhouse gas, and changes in its biogeochemical cycle can influence the global climate system. Extreme shifts in atmospheric and marine CH₄ emissions have happened in the past. In marine environments, aerobic methane oxidation (AMO) is the last CH₄ sink before it reaches the atmosphere, and thus plays an important role in regulating marine CH4 emissions.

The Deepwater Horizon blowout in April 2010 caused the largest marine oil spill in history (∼4.4 x 10⁶ ± 20% barrels of oil). The oil and gas that was discharged into the water column stimulated the growth of multiple methanotrophs and other hydrocarbon utilizing bacteria. Bacteria performing AMO synthesize specific bacteriohopanepolyols (BHPs) that are used as lipid biomarkers for AMO. To investigate possible community shifts induced by an extreme gas emission event we collected sinking particulate matter before and after the blowout to identify BHPs of the local bacterial community performing AMO. Our study aims to elucidate the interplay between extreme methane emissions into the ocean and aerobic methanotrophy in the water column. Moreover, the results of this study will be used to interpret past BHP distribution and abundances in sediment records in the Gulf of Mexico.