Two years after the Deepwater Horizon drilling disaster in the Gulf of Mexico, the extent of its ecological impact is still to be fully assessed. In field studies from coastal marsh areas four months after the spill, exposure to the oil has been linked to divergence in genomic expression and aberrant protein expression in killifish (Fundulus grandis) gills, indicative of exposure to hydrocarbon-like chemicals. Deep water coral communities are also affected: in a study by Fisher and colleagues four months following capping of the well at a site 11 km from the Macondo well, widespread signs of stress in corals (tissue loss, bleaching and covering by brown flocculent material – floc) were visible. Analyses of the floc adherent to corals show petroleum biomarkers associated with the spill.
In a recent paper published in BMC Biology, Michael Barresi and colleagues report the results of an investigation of the possible lasting damage to marine life using the well characterized laboratory zebrafish as a powerful model for assessing the effects of toxicants from oil samples on embryonic development. They found that water-soluble components of crude oil samples from the Deepwater Horizon disaster containing polycyclic aromatic hydrocarbons cause defects in embryonic zebrafish development, leading to circulatory, locomotor and brain defects.They were also able to identify some of the molecular pathways activated by the oil.
Following the second anniversary of the Deepwater Horizon oil spill (on April 20), a panel of experts funded by the National Center for Ecological Analysis and Synthesis have recommended that strategies to deal with such deep water spills may need to change in future to meet the special ecological challenge of oil retained at depth in the ocean. In light of the research by Barresi and colleagues on zebrafish, it seems that profound effects of the oil spill may continue to surface and the committee’s concerns on the ecological risk are well founded.
J. Ann Le Good, Deputy Editor, BMC Biology