A perspective of the Gulf effort that's different from the media's

[ProSense]

A team of University of Georgia marine scientists is conducting research on the huge underwater oil plume that was discovered in the aftermath of the Deepwater Horizon oil rig explosion. Throughout a two-week cruise in the Gulf of Mexico, they are posting regular updates and photos to this blog.

The team now on board the R/V F.G. Walton Smith is led by Samantha Joye, UGA professor of marine sciences, Franklin College of Arts and Sciences. Joye was a member of the NOAA-supported expedition that discovered the deepwater plumes thousands of feet below the surface in the Gulf of Mexico, about two weeks ago.

The group sailed from Gulfport, Miss., on Tuesday, May 25, on a scientific mission to characterize and visualize the largest of the underwater oil plumes, estimated to be more than 15 miles long, 5 miles wide and some 300 feet thick at depths ranging from approximately 2,300 feet to 4,200 feet. This plume is currently located to the south/southwest of the Deepwater Horizon site.

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Day three in the city of ships

By Samantha Joye | Published: May 28, 2010 5:32am

May 28th, 01:00. Today we saw some new sites around the area. A fleet of skimmer ships was doing a surface burn to reduce the size of an oil slick (see photo). We were a couple of miles away from the burn but the large cloud of black smoke caught everyone’s eye. I’m still amazed by the ‘city of ships’ around the spill site (see photo). The rigs drilling the relief wells and the ‘siphon’ ship (large ship to the left of the photo), as well as many support vessels are visible in this shot.

Our sampling and general operations are going very smoothly. We ran CTD profiles all through Wednesday night and Thursday morning, thanks to the efforts of Vernon Asper from the University of Southern Mississippi. We tracked the ‘new’ plume along a S/SW line by doing CTD casts about every half mile. The main plume features were fairly consistent along the line can concentrations of CDOM decreased with distance from the spill site.

Around 10AM Thursday morning, we moved slightly to the North and found another very interesting plume that was different from the previous one. The second plume contained less CDOM but exhibited more oxygen depletion. Perhaps this plume is older than the other one? The oxygen concentrations are not low enough to harm animal life but they are substantially lower (by ~25%) than the waters outside the plume at similar depths. Methane concentrations in this feature are the highest we’ve measured anywhere so far during this cruise.

This is an extensive plume. We’ve been tracking it now for approximately 7 miles and both the CDOM signal as well as oxygen depletion are strong and they co-vary. The samples with oxygen depletion also contain high concentrations of methane. Our hypothesis is that methane oxidation and CDOM degradation are driving oxygen consumption. We will be testing this hypothesis directly by measuring methane oxidation rates and oxygen consumption rates. Back at the UGA lab, we’ll be doing experiments to determine what factors regulate methane oxidation rates in these samples.

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h/t n2doc