Please select your home edition
Edition
Protector 728x90

WHOI Study - Microbes consumed oil in Gulf slick at unexpected rates

by Woods Hole Oceanographic Institution on 21 Aug 2011
From the deck of the research vessel Endeavor, Ben Van Mooy (right) and others survey the scene near the burning Deepwater Horizon oil rig in the Gulf of Mexico in June, 2010. Van Mooy was a member of a team of WHOI scientists who went to the Gulf to study aspects of the oil spill, including how fast it was flowing out of the ruptured wellhead and whether it was flowing in a deep plume of hydrocarbons. Van Mooy’s experiments focused on whether microbes were eating oil in the surface slick and in Woods Hole Oceanographic Institution (WHOI) © http://www.whoi.edu/
More than a year after the largest oil spill in history, perhaps the dominant lingering question about the Deepwater Horizon spill is, 'What happened to the oil?' Now, in the first published study to explain the role of microbes in breaking down the oil slick on the surface of the Gulf of Mexico, Woods Hole Oceanographic Institution (WHOI) researchers have come up with answers that represent both surprisingly good news and a head-scratching mystery.

In research scheduled to be published in the Aug. 2 online edition of Environmental Research Letters, the WHOI team studied samples from the surface oil slick and surrounding Gulf waters. They found that bacterial microbes inside the slick degraded the oil at a rate five times faster than microbes outside the slick—accounting in large part for the disappearance of the slick some three weeks after Deepwater Horizon’s Macondo well was shut off.

At the same time, the researchers observed no increase in the number of microbes inside the slick—something that would be expected as a byproduct of increased consumption, or respiration, of the oil. In this process, respiration combines food (oil in this case) and oxygen to create carbon dioxide and energy.

'What did they do with the energy they gained from this increased respiration?' asked WHOI chemist Benjamin Van Mooy, senior author of the study. 'They didn’t use it to multiply. It’s a real mystery,' he said.

Van Mooy and his team were nearly equally taken aback by the ability of the microbes to chow down on the oil in the first place. Going into the study, he said, 'We thought microbe respiration was going to be minimal.' This was because nutrients such as nitrogen and phosphorus—usually essential to enable microbes to grow and make new cells—were scarce in the water and oil in the slick. 'We thought the microbes would not be able to respond,' Van Mooy said.

But the WHOI researchers found, to the contrary, that the bacteria not only responded, but did so at a very high rate. They discovered this by using a special sensor called an oxygen optode to track the changing oxygen levels in water samples taken from the slick. If the microbes were respiring slowly, then oxygen levels would decrease slowly; if they respired quickly, the oxygen would decrease quickly.

'We found that the answer was ‘quick,’' Van Mooy said. 'By a lot.'

Bethanie Edwards, a biochemist in Van Mooy’s lab and lead author of the paper, said she too was 'very surprised' by the amount of oil consumption by the microbes. 'It’s not what we expected to see.' She added that she was also 'a little afraid' that oil companies and others might use the results to try to convince the public that spills can do relatively little harm. 'They could say, ‘Look, we can put oil into the environment and the microbes will eat it,’' she said.

Edwards, a graduate student in the joint MIT/WHOI program, pointed out that this is not completely the case, because oil is composed of a complex mixture molecules, some of which the microbes are unable to break down.

'Oil is still detrimental to the environment, ' she said, 'because the molecules that are not accessible to microbes persist and could have toxic effects.' These are the kinds of molecules that can get into the food web of both offshore and shoreline environments, Edwards and Van Mooy said. In addition, Edwards added, the oil that is consumed by microbes 'is being converted to carbon dioxide that still gets into the atmosphere.'

Follow-up studies already 'are in place,' Van Mooy says, to address the 'mysterious' finding that the oil-gorging microbes do not appear to manufacture new cells. If the microbes were eating the oil at such a high rate, what did they do with the energy?

Van Mooy, Edwards, and their colleagues hypothesize that they may convert the energy to some other molecule, like sugars or fats. They plan to use 'state-of-the-art methods' under development in their laboratory to look for bacterial fat molecules, a focus of Van Mooy’s previous work. The results, he says, 'could show where the energy went.'

Van Mooy said he isn’t sure exactly what fraction of the oil loss in the spill is due to microbial consumption; other processes, including evaporation, dilution, and dispersion, might have contributed to the loss of the oil slick. But the five-fold increase in the microbe respiration rate suggests it contributed significantly to the oil breakdown.

'Extrapolating our observations to the entire area of the oil slick supports the assertion microbes had the potential to degrade a large fraction of the oil as it arrived at the surface from the well,' the researchers say in their paper.

'This is the first published study to put numbers on the role of microbes in the degradation of the oil slick,' said Van Mooy. 'Our study shows that the dynamic microbial community of the Gulf of Mexico supported remarkable rates of oil respiration, despite a dearth of dissolved nutrients,' the researchers said.

Edwards added that the results suggest 'that microbes had the metabolic potential to break down a large portion of hydrocarbons and keep up with the flow rate from the wellhead.'

Also participating in the study from WHOI were researchers Christopher M. Reddy, Richard Camilli, Catherine A. Carmichael, and Krista Longnecker.

The research was supported by RAPID grants from the National Science Foundation.

Woods Hole Oceanographic Institution website

The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean's role in the changing global environment.

Giacomo Yacht SaleMariners Museum 660x82Southern Spars - 100

Related Articles

Int Moth Worlds - Zhik returns to its spiritual home at 2017 Worlds
Zhik is returning to its roots as the official clothing sponsor of the 2017 McDougall McConaghy Moth World Championships Zhik, the innovative sailing apparel specialist, is returning to its roots as the official clothing sponsor of the 2017 McDougall McConaghy Moth World Championships. And, ten years on, the Moths are returning to their spiritual home on Lake Garda. Zhik and the International Moth class are virtually synonymous with each other.
Posted on 20 Jul
World Sailing confirms strong presence at Yacht Racing Forum 2017
The tenth edition of the Yacht Racing Forum, in Aarhus, Denmark will reassemble the sport’s key personalities and actors The tenth edition of the Yacht Racing Forum, in Aarhus, Denmark (November 27-28) will once again reassemble the sport’s key personalities and actors, including a strong delegation of World Sailing representatives.
Posted on 19 Jul
Watch Change in Crosshaven - UK Sailmakers under new command
'Our strength has always been service, quality and people. Right now, they are Graham, Claire and Barry.' The famous Crosshaven loft that is part of the UK Sailmakers organisation will shortly have a new crew on deck. Barry Hayes, Claire Morgan and Graham Curran are taking over from Des McWilliam who is stepping down after 39 years in the business and 25 years at the helm of McWilliam Sailmakers.
Posted on 3 Jul
A Few Rays – Moisturising, Anti-Aging Action …
Consistent moisturising sun protection has an anti-aging action Consistent moisturising sun protection has an anti-aging action Out on a boat, sailors are exposed to extreme conditions for their skin. There are UV rays from the sun, hopefully some wind if you are a sailor, and the drying effects from wet and dry cycles during the course of your day
Posted on 23 Jun
When the going gets hot Zhik has the answers on what to wear afloat
Whilst many of us Brits are looking in the sailing bag wondering what on earth to wear afloat in this heatwave Whilst many of us Brits are looking in the sailing bag wondering what on earth to wear afloat in this heatwave, Zhik the Australian sailing apparel innovators are set up for dealing with extreme heat, moisture management and sun protection.
Posted on 22 Jun
BoatUS looks at accuracy of 22 Years of hurricane season predictions
BoatUS Seaworthy Program, which helps BoatUS members avoid injuries and boat damage by analyzing insurance claims data With most 2017 storm forecasts now predicting average to above-average storm activity for the 2017 Atlantic Hurricane Season (June 1 – November 30), just how accurate are these predictions, and do boaters need to adjust their hurricane prep plans this year?
Posted on 13 Jun
Caffari to lead a team with sustainability message in Volvo Ocean Race
Sixth confirmed team out of a possible eight for the upcoming edition will amplify United Nations Environment’s campaign Caffari’s ambition is to build a multi-national, 50-50 male/female squad, with the majority under 30 years of age. As part of the sustainability focus, the messages around diversity in age and gender will be strong themes of a campaign that in sporting terms may not start as a favourite, but could easily surprise on the water.
Posted on 13 Jun
AkzoNobel named as official supplier to the Volvo Ocean Race Boatyard
The competing boats– including team AkzoNobel’s brand new Volvo Ocean 65– have already been coated with Awlgrip products AkzoNobel will be the official coatings supplier to the Volvo Ocean Race Boatyard in 2017-18, after signing a deal to ensure that the fleet of Volvo Ocean 65 racing yachts will be coated with the company’s International and Awlgrip range of products
Posted on 29 May
World Sailing and Volvo join forces for the future of sailing
The partnership is a signal of the Volvo Ocean Race's commitment to the sport and future of offshore sailing. As part of an ambitious plan, World Sailing will partner with the Volvo Ocean Race, owned by Volvo Group and Volvo Car Group, to develop the next generation of offshore sailors.
Posted on 18 May
TIMEZERO by MaxSea extends navigation partnership with Clipper Race
TIMEZERO by MaxSea, has been named as the Official Navigation Software Supplier for Clipper Round the World Yacht Race. Returning for its second race partnership, TIMEZERO by MaxSea, has been named as the Official Navigation Software Supplier for the Clipper 2017-18 Round the World Yacht Race.
Posted on 18 May