Featured Research

from universities, journals, and other organizations

Deep below the Deepwater Horizon oil spill: New molecular model better explains diffusion of spill under water

Date:
July 18, 2011
Source:
Ecole Polytechnique Fédérale de Lausanne
Summary:
For the first time, scientists gathered oil and gas directly as it escaped from a deep ocean wellhead -- that of the damaged Deepwater Horizon oil rig. What they found allows a better understanding of how pollution is partitioned and transported in the depths of the Gulf of Mexico and permits superior estimation of the environmental impact of escaping oil, allowing for a more precise evaluation of previously estimated repercussions on seafloor life in the future.

This is a graphic explanation of escaped petroleum dispersion 1,000 meters below the sea.
Credit: EPFL

For the first time, scientists gathered oil and gas directly as it escaped from a deep ocean wellhead -- that of the damaged Deepwater Horizon oil rig. What they found allows a better understanding of how pollution is partitioned and transported in the depths of the Gulf of Mexico and permits superior estimation of the environmental impact of escaping oil, allowing for a more precise evaluation of previously estimated repercussions on seafloor life in the future.

The explosion of the Deepwater Horizon rig in April 2010 was both a human and an environmental catastrophe. Getting the spill under control was an enormous challenge. The main problem was the depth of the well, nearly 1,500 meters below the sea surface. It was a configuration that had never been tried before, and the pollution it unleashed after methane gas shot to the surface and ignited in a fiery explosion is also unequalled. Much research has been done since the spill on the effects on marine life at the ocean's surface and in coastal regions. Now, École Polytechnique Fédérale de Lausanne (EPFL) professor Samuel Arey and the Woods Hole Oceanographic Institute reveal in the advance online edition of Proceedings of the National Academy of Sciences how escaped crude oil and gas behave in the deep water environment.

Into the deep

In June 2010, with the help of a remotely operated vehicle (ROV), Woods Hole scientists reached the base of the rig and gathered samples directly from the wellhead using a robotic arm. The oceanographers also made more than 200 other measurements at various water depths over a 30-kilometer area. These samples were then analyzed with the help of the US National Oceanic and Atmospheric Administration and the dissolution of hydrocarbons was modeled at EPFL. This model showed how the properties of hydrocarbons are important in understanding the wellhead structure and pollution diffusion -- how pollution spreads out -- in the depths.

From the ROV to the lab

Lab analysis led the scientists to describe for the first time the physical basis for the deep sea trajectories of light-weight, water-soluble hydrocarbons such as methane, benzene, and naphthalene released from the base of the rig. The researchers observed, for example, that at a little more than 1,000 meters below the surface, a large plume spread out from the original gusher, moving horizontally in a southwest direction with prevailing currents. Unlike a surface spill, from which these volatile compounds evaporate into the atmosphere, in the deep water under pressure, light hydrocarbon components predominantly dissolve or form hydrates, compounds containing water molecules. And depending on its properties, the resulting complex mixture can rise, sink, or even remain suspended in the water, and possibly go on to cause damage to seafloor life far from the original spill.

By comparing the oil and gas escaping from the well with the mixture at the surface, EPFL's Samuel Arey, head of Environmental Chemistry Modeling Laboratory, and colleagues were able to show that the composition of the deep sea plumes could be explained by significant dissolution of light hydrocarbons at 1 kilometer depth. In other words, an important part of the oil spreads out in underwater plumes, so we need a more precise evaluation of previously estimated repercussions on seafloor life in the future. Arey's methodology offers a better estimation of how pollution travels and the potential deep sea consequences of spills.

"Modeling the environmental fate of hydrocarbons in deep water ecosystems required a new approach, with a global view, in order to correctly understand the impact of the pollution," explains Arey. This research will have a significant impact on assessments of the environmental impact of deep water oil spills.


Story Source:

The above story is based on materials provided by Ecole Polytechnique Fédérale de Lausanne. Note: Materials may be edited for content and length.


Journal Reference:

  1. Christopher M. Reddy, J. Samuel Arey, Jeffrey S. Seewald, Sean P. Sylva, Karin L. Lemkau, Robert K. Nelson, Catherine A. Carmichael, Cameron P. McIntyre, Judith Fenwick, G. Todd Ventura, Benjamin A. S. Van Mooy, Richard Camilli. Science Applications in the Deepwater Horizon Oil Spill Special Feature: Composition and fate of gas and oil released to the water column during the Deepwater Horizon oil spill. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1101242108

Cite This Page:

Ecole Polytechnique Fédérale de Lausanne. "Deep below the Deepwater Horizon oil spill: New molecular model better explains diffusion of spill under water." ScienceDaily. ScienceDaily, 18 July 2011. <www.sciencedaily.com/releases/2011/07/110718151549.htm>.
Ecole Polytechnique Fédérale de Lausanne. (2011, July 18). Deep below the Deepwater Horizon oil spill: New molecular model better explains diffusion of spill under water. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2011/07/110718151549.htm
Ecole Polytechnique Fédérale de Lausanne. "Deep below the Deepwater Horizon oil spill: New molecular model better explains diffusion of spill under water." ScienceDaily. www.sciencedaily.com/releases/2011/07/110718151549.htm (accessed October 21, 2014).

Share This



More Earth & Climate News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) — He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) — Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
White Rhino's Death In Kenya Means Just 6 Are Left

White Rhino's Death In Kenya Means Just 6 Are Left

Newsy (Oct. 20, 2014) — Suni, a rare northern white rhino at Ol Pejeta Conservancy, died Friday. This, as many media have pointed out, leaves people fearing extinction. Video provided by Newsy
Powered by NewsLook.com
New Organic Fertilizer Helps Reforestation of Monarch Butterflies’ Winter Retreat

New Organic Fertilizer Helps Reforestation of Monarch Butterflies’ Winter Retreat

Reuters - Innovations Video Online (Oct. 20, 2014) — Using an organic fertiliser, a conservationist from the National Autonomous University of Mexico (UNAM), leads an award-winning project to reforest the sanctuary of monarch butterflies. Sharon Reich reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

More Coverage


Chemical Make-Up of Gulf of Mexico Plume Determined

July 20, 2011 — Taking another major step in sleuthing the 2010 Deepwater Horizon oil spill, scientists have determined what chemicals were contained in a deep, hydrocarbon-containing ... read more

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins