To the naked eye, "the oil can disappear, but we don't know the long-term effects on organisms and their population fitness," he says.
The open ocean is a particularly complex environment to understand, other researchers say. Research requires expensive ships, and many factors can affect the health of marine life at all levels of the water column, making it tough to single oil out from other stresses both human and natural.
But a concerted effort is afoot to use the BP oil spill as an opportunity to better understand deep water oil spills.
BP, which owns the exploratory well the Deepwater Horizon was working when the blowout occurred April 20, has offered $500 million over the next 10 years to underwrite research and monitoring efforts. Moreover, the National Science Foundation, which underwrites research by university-based scientists, has made quick-response grants available for gauging the spill's ecological effects.
For instance, scientists are trying to see if the wide use of chemical dispersants – more than 600,000 gallons so far – undercuts the ability of naturally occurring microbes to break down the oil.
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.