ABERDEEN, UK – Researchers at the University of Aberdeen believe sub-zero temperatures in the deepwaters of the North Atlantic would impact oil-spill counter measures.
A team of scientists tested the ability of oil-degrading microorganisms found in deepwater sedimentswest of Shetland, where there are several major oil fields.
Microorganisms in the warmer waters of the Gulf of Mexico are thought to have aided recovery of escaped oil from theDeepwater Horizon incident in 2010, although large volumes of oil still reached the seafloor.
According to the university, oil build-up in ocean floor sediments can persist for decades, with harmful effects.
To improve understanding of 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 (32°F) - similar to those experienced in the deepwaters of the North Atlantic and Arctic - than at 5°C (41°F), as in theGulf of Mexico.
They also concluded that theapplication of dispersant, a common technique used to help clear major spills, would have variable effects, suggesting care should be taken in deciding whether to apply these chemicals as part of an oil spill response.
Professor Ursula Witte, senior author of the study, said: “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.
“The results also show that we do not fully understand the consequences of using dispersants in the cold or deep ocean. Careful consideration is needed before this is adopted as a strategy for cleaning up an oil spill in the deep-sea.”
The full paper –The Variable Influence of Dispersant on Degradation of Oil Hydrocarbons in Subarctic Deep-Sea Sediments at Low Temperatures (0-5°C) is available at www.nature.com/articles/s41598-017-02475-9.