BP oil spill: an unexpected laboratory for deep-sea disaster
The BP oil spill is a unique event, so scientists are converging on the Gulf to try to understand how best to combat deep-sea oil spills and what effects they have on the environment.
(Page 2 of 3)
On one hand, as dispersants break a slick into tiny oil droplets, more microbes get a chance to attack the oil, notes Qianxin Lin, a coastal ecologist at Louisiana State University in Baton Rouge. Microbes can attack oil droplet from every side. In a typical slick, they just nibble at the edges.Skip to next paragraph
In Pictures Louisiana oil spill
Subscribe Today to the Monitor
Yet dispersants also may also inhibit the chemicals microbes produce to gather and consume the oil, according to University of California at Santa Barbara researcher David Valentine. Armed with one of the rapid-response grants, he's heading to the Gulf to gauge the microbes' responses to dispersants.
Where does the oil go?
Scientists also want to know the amount of oil likely to come to rest on the sea bottom. On the surface, oil weathers, grows dense, and sinks. But in the BP oil spill, much of the oil never makes it to the surface.
Carefully controlled experiments a decade ago released small quantities of oil from a depth about half that of the Deepwater Horizon's Macondo well, and they revealed some surprises, notes Eric Adams, a scientist at the Massachusetts Institute of Technology who was involved in the work.
"One of the take-home messages was that most of the oil does not immediately reach the surface," he says, noting that this is also true of the oil in the BP oil spill.
Moreover, oil that did reach the surface arrived faster than models of oil behavior suggested, he says.
"We need a lot more research on plume dynamics," he says, referring to the mechanisms that prevent the oil from reaching the surface.
One factor is the sheer energy of oil leaving a wellhead. It is enough to begin breaking the oil into smaller blobs, and the behavior of oil varies according to the size of the blobs. Undersea currents also play a role in breaking down oil and disperses it over a wider area than the plume alone covers. Dispersants add yet another level of complexity to plume dynamics, Dr. Adams says.
All of these things could have an effect on deep-sea ecosystems. Within the past four years, Gulf research cruises conducted by the National Oceanic and Atmospheric Administration and the US Minerals Management Service have uncovered deep-ocean reefs, along with animals ranging from football-sized mussels to tube worms and shrimp.