"The concentrations that are currently out there in various locations are high enough to have a toxic effect on marine life," said Charles Hopkinson, also of the University of Georgia's marine sciences program.
NOAA Administrator Jane Lubchenco, the government's top ocean scientist, has acknowledged concerns over the effects of dissolved oil, but has said that chemical dispersants had largely done their job.
"Nobody should be surprised," Joye said. "When you apply large scale dispersants, it goes to the bottom -- it sediments out. It gets sticky."
ABC News' Susan Schwartz contributed to this report.