By Janet Raloff
LONG BEACH, Calif. — Two years after BP’s Deepwater Horizon well blowout, laboratory studies are finally offering clues to the spilled oil’s impact on sea life. Brief, very low exposures to oil were capable of killing many fish embryos and hatchlings, new studies show. Those that survived often exhibited major deformities that would diminish an animal’s fitness.
Affected species ranged from the young of large open-ocean denizens, such as tuna, to minnow-sized coastal homebodies — the tiny fish that serve as lunch for everyone bigger. Researchers shared their findings in mid-November during a symposium at the Society of Environmental Toxicology and Chemistry’s annual meeting.
Among oil constituents that most threaten sea life are polycyclic aromatic hydrocarbons, or PAHs. Through a process known as weathering, lighter-weight chemicals evaporate off of fresh oil, rendering what’s left progressively heavier and sludgy. New chemical analyses show that weathering reduces oil’s propensity to shed PAHs into water, finds Damian Shea of North Carolina State University in Raleigh. The bottom line, he concludes: Weathering reduces oil toxicity.