“Tiny” amounts of crude oil on the sea surface can damage seabird feathers, according to a University College Cork (UCC) study.
Oil less than one percent of the thickness of a hair can cause harm, researchers from UCC’s Marine Ecology Group state.
The team collected feathers from Manx shearwaters, a seabird species thought to be at-risk from oil pollution, and examined them to see how quickly water would pass through after exposure to increasing concentrations of oil.
Feathers were also assessed under high-powered microscopes to examine structural changes after contamination, they state.
The research found that really thin oil sheens, between 0.1 and 3 micrometres in thickness, were “enough to have a significant effect on feather structure and impacted waterproofing”.
Other studies have shown that seabirds exposed to oil are more likely to become waterlogged, cold, and less buoyant.
Environmental disasters such as the Exxon Valdez and Sea Empress spills have released unrefined oil, or crude oil, into the sea in huge volumes.
Crude oil is also routinely released into the environment in moderate volumes due to extraction and transport activity, the researchers note.
“Chronic small-scale oil pollution is commonly overlooked in the marine environment, though it has been shown to have serious implications for the fitness and survival of seabirds,” Emma Murphy, lead author of the study, says.
“This study examined one species, but the results can be extended to other species that rely on waterproofing to stay healthy when at sea for long periods,” she says.
The research is published in the journal Open Science.