Sub-zero waters a barrier to oil spill recovery

Sub-zero waters a barrier to oil spill recovery
Scientists at the University of Aberdeen have tested the ability of oil-degrading microorganisms found in deep water sediments west of Shetland. Credit: University of Aberdeen

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 new research.

In the first study of its type, scientists at the University of Aberdeen 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 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 can persist for decades and cause harmful effects. 

To better understand the oil-degrading abilities of microorganisms in colder waters, 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 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.

Overall, the study has provided evidence that the environmental consequences of a major spill in colder waters would last far longer than other deep drilling environments.

Professor Ursula Witte is the senior author of the study, co-authored by Professor Jim Anderson, Evangelia Gontikaki and Dr Robert Ferguson, who is now at the University of Essex.  The study has been published in Scientific Reports

Professor Witte 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.

"Understanding the environmental implications of an oil spill in the cold and deep ocean is therefore urgent to improve our response to a potential spill.

"This study is the first to confirm that hydrocarbon degradation in sediments at 0 °C is significantly slower than at 5 °C.

"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."

Dr Ferguson added: "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 in the deep sea."


Explore further

Researchers ask important questions on what happens to oil after a spill

More information: Robert M. W. Ferguson et al. The Variable Influence of Dispersant on Degradation of Oil Hydrocarbons in Subarctic Deep-Sea Sediments at Low Temperatures (0–5 °C), Scientific Reports (2017). DOI: 10.1038/s41598-017-02475-9
Journal information: Scientific Reports

Citation: Sub-zero waters a barrier to oil spill recovery (2017, May 24) retrieved 17 October 2019 from https://phys.org/news/2017-05-sub-zero-barrier-oil-recovery.html
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May 24, 2017
The US Secretary of Exxon State will ignore those barriers, like any other barriers to his half-$TRILLION deal for extracting oil/gas from icy Russian waters.

May 24, 2017
and yet everyone realizes that petroleum seeps are naturally occurring and raw petroleum has been, is and will continue seeping into sub-zero water for now until the planet dies

May 24, 2017
And yet everyone but you climate denial trolls and pollution cronies realize that toxins, even nutrients, that ecosystems have evolved to cope with are overwhelming when suddenly blasted through the area. Please stick a firehose up your nose the next time you have the sniffles.

Shootist:
and yet


May 25, 2017
Article needs to explain how it is that sub-zero temps are possible in sea water. (It's the salinity.)

And maybe someone can explain to me why a study which "discovered" that metabolism decreases with temperature would be news to anyone.

May 25, 2017
and yet everyone realizes that petroleum seeps are naturally occurring and raw petroleum has been, is and will continue seeping into sub-zero water for now until the planet dies -shootist

As an example, the annual natural oil seepage distributed throughout the entire Gulf of Mexico is estimated at 70,000 tonnes/year whereas the British Petroleum Deepwater Horizon oil spill released 700,000 tonnes, most during a period of 87 days, i.e. 40x the annual rate. 40 times! So much methane was released that the resulting bacterial bloom created anoxic dead zones.
https://www.thegu...eadzones Your implication that somehow oil spills are the same as natural seepage is disingenuous at best, lying, manipulative, and deceitful at worst.

May 25, 2017
barakn: [qAs an example

BP's Macondo blowout dumped actually 42x the baseline seepage, which is an *additional* blast atop the natural rate. And it wasn't spread across the entire Gulf, and wasn't concentrated in places particularly suited to spikes. "In some cases [in post-BP Gulf], methane concentrations are 100,000 times normal levels."

The vast dieoffs across the ecosystem actually witnessed (even to our superficial observations) show it was catastrophic.

And even the baseline seepage is under drilling pressure. Even the baseline ecology is under runoff pressure from the oil/gas industry.

People like Shootist who lie to minimize these catastrophes are guilty of perpetuating them. Guilty.

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