New study finds sub-zero waters as barrier to oil spill clean up
Sub-zero temperatures in the deep waters of the North Atlantic would significantly hamper the ability of oil-eating bacteria to help the ocean recover from a major oil spill, according to a new paper issued by University of Aberdeen.
In the first study of its type, entitled “The Variable Influence of Dispersant on Degradation of Oil Hydrocarbons in Subarctic Deep-Sea Sediments at Low Temperatures (0–5 °C)”, scientists have tested the ability of oil-degrading microorganisms found in deep water sediments west of Shetland, which is home to several major oil fields.
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 and cause harmful effects.
Findings
- Scientists analysed 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 such as those in the Gulf of Mexico.
- Results also show 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.
Professor Ursula Witte, co-author of the study, said: “Depleting oil reserves has forced the industry to explore progressively deeper waters, and the dramatic shrinking of Arctic sea ice means that previously inaccessible reserves are now considered for exploration.
She added: “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.”
Co-author Dr Robert Ferguson noted that the results from the study show that people do not fully understand the consequences of using dispersants in the cold or deep ocean, and this strategy should not be adopted when cleaning up an oil spill in the deep sea.
Explore more at the official paper herebelow: