Genome Expression Response of Resident Killifish Impacted by the Deepwater Horizon Oil Spill

Gulf killifish (Fundulus grandis) are the most abundant vertebrate in coastal marsh ecological communities and are economically-important bait fishes.  Large populations of killifish inhabit Gulf-exposed marsh habitats that are at high risk of contamination from oil spilled in the Gulf of Mexico; indeed much habitat was oiled following the Deepwater Horizon oil spill.  For these reasons, these killifish are strategic models for assessing contaminating oil impacts on Gulf coast marshes.  We have launched a project intended to characterize oil spill impacts on the coastal marsh by integrating genomic and physiological indicators of response to oil exposure in situ and under controlled exposure conditions.  In field studies genome expression within livers of resident fish was tracked across space (contaminated and reference sites) and time (pre-oil, during oil, and after oil exposure).  Genome expression was most distinct at our only field site out of six that was clearly impacted by oil, and at the peak of oil contamination documented by satellite imagery and analytical chemistry, showing a clear genomic footprint of oil exposure.  This genomic response is similar to that observed following controlled PCB exposures to developing embryos, which caused developmental abnormalities and death.