The microbes that once thrived around deep-sea shipwrecks in the Gulf of Mexico have transformed significantly after the Deepwater Horizon oil spill in 2010, according to a new study. These dramatic changes to the microorganisms that live on and near historically significant vessels could wreak havoc on the vessels and ocean life itself, researchers say.
In 2010, the Gulf of Mexico experienced the worst man-made environmental disaster in U.S. history, after explosions at the Deepwater Horizon oil rig caused more than 170 million gallons (643 million liters) of oil to spill into the water. In 2014, scientists launched a project to investigate the impacts of this catastrophe on deep-sea shipwrecks and the ecosystems they support in the Gulf — an estimated 30 percent of the oil from the spill ended up deposited in the deep sea, in areas that contain shipwrecks, the researchers said.
The scientists found that shipwrecks influence which microbes are present on the seafloor. These microbes in turn form the foundation for other life, such as coral, crabs and fish. Furthermore, the researchers found the Deepwater Horizon oil spill had a dramatic effect on nearby shipwreck microbial communities even four years after the disaster. Such changes might in turn impact other parts of their ecosystems, the researchers said.
Specifically, in sediment layers within the Deepwater Horizon oil plume, the scientists detected “oil snow” — cell debris and other chemicals produced by microorganisms that have come into contact with oil, making the oil heavy and causing it to sink rather than float. In this oil snow, the researchers found DNA from bacteria whose closest relatives break down oil for energy.
By changing what microbes dominate shipwreck habitats, the Deepwater Horizon oil spill may have had untold effects on those ecosystems, the researchers said. The scientists also found that exposure to oil spurred microbes to increase metal corrosion. This suggests that the oil spill could potentially speed up degradation of steel-hulled wrecks, said Salerno, a collaborator on the research project.
Source: Live Science