A deep water oil spill in the northeast Atlantic would be more difficult to combat than the Deepwater Horizon spill of 2010, and the use of a dispersant in those waters would create a subsea ‘dirty blizzard' of marine oil snow, according to new research from Heriot-Watt.
The new research from the university's Institute of Mechanical, Process & Energy Engineering (IMPEE), published in Frontiers in Microbiology, shows that the use of a dispersant in the Faroe-Shetland Channel after an oil spill would trigger conditions similar to the aftermath of Deepwater Horizon: the formation of marine oil snow (MOS).
MOS comprises sticky, floating organic particles that are visible to the naked eye and contain oil droplets from spills. MOS sinks rapidly, which has two effects: it vanishes much of the oil from the surface, leading observers to think the spill has been cleaned up, and it carries the oil to the seabed, with potentially damaging effects on deep sea ecosystems.
The rapid sinking of copious quantities of MOS to the seabed was the ‘dirty blizzard' that occurred during the Deepwater Horizon spill, and may have accounted for vast quantities of oil that impacted much of the continental slope in the northern Gulf of Mexico around the Macondo wellhead.
Dr Tony Gutierrez, Associate Professor of Microbiology at Heriot-Watt University, said, “The Faroe-Shetland Channel is at the frontier of deep water petroleum exploration, so there is a pressing need for fundamental research in this region.
“The area is already home to oil rigs that are extracting oil at depths of down to 500m, and the region is being scoped for oil at much greater depths.
"The possibility of a deep sea spill in this area in the future cannot be discounted, so it's vital we know how to respond."
Laura Duran Suja, a PhD student at Heriot-Watt University and member of the NERC Centre for Doctoral Training (CDT) in Oil & Gas, led the study and took surface seawater samples from the water mass known as the Modified North Atlantic Wester (MNAW), near the Schiehallion oil field, and incubated them with the oil under conditions simulating the sea surface.
Over the course of six weeks she studied the microbial response, including of the oil-degrading bacterial communities, and observed the formation of MOS in incubations treated with dispersant and/or nutrients.
Dr Gutierrez said: “Our data indicates that in the event of an oil spill in the Faroe-Shetland Channel, the use of dispersants could trigger the formation of MOS. The good news is that the MOS harbours rich communities of oil-degrading bacteria, which have an important role in ‘eating' up the oil.”
This work is the first of its kind to test dispersants on the microbial response and formation of MOS in the event of an oil spill in the Faroe-Shetland Channel.
For more information, visit the Gutierrez Group research page: http://www.tony-gutierrez.com/.