Scientists at the University of Aberdeen in Scotland have found that sub-zero temperatures significantly hamper the ability of oil-eating bacteria to help the ocean recover from an oil spill.
Microorganisms found in the ocean played an important role in breaking up millions of gallons of oil that spilled into the Gulf of Mexico as a result of the Deepwater Horizon disaster in 2010. The warm waters and abundance of oil-eating bacteria are thought to have significantly aided recovery, however a large amount of oil still reached the seafloor. Oil accumulating in ocean floor sediments can persist for decades.
To better understand the oil-degrading abilities of microorganisms in colder waters, the scientists analyzed samples from west of Shetland and found that degradation was considerably lower at temperatures of 0°C, similar to those experienced in the deep waters of the North Atlantic and Arctic, than at 5°C, similar to those experienced in the Gulf of Mexico.
The research also showed that the application of dispersant – a common technique used to help clear major spills - had variable effects, suggesting care should be taken when deciding whether to apply these chemicals as part of an oil spill response.
Overall, the study provided evidence that the environmental consequences of a major spill in colder waters would last far longer than other deep water drilling environments.
“The fact that certain hydrocarbons we tested did not show any detectable levels of degradation at 0 °C suggests that the impact of oil contamination at near zero or sub-zero temperatures would have a severe long term impact on the marine environment,” said Professor Ursula Witte, senior author of the study.
The study is available here.