Scientists have investigated the effects of surface crude oil on the feather structure of the Manx shearwater (Puffinus puffinus), a species of seabird that spends a high proportion of time on the water surface. Surface oil as thin as 0.1 µm (micrometers) was enough to increase feather permeability, while greatest impacts on permeability were caused by exposure to dark color surface sheens 3 µm in thickness.
“Industrialization of the marine environment is continuously intensifying, with all marine habitats affected by at least one anthropogenic influence,” said University College Cork researcher Emma Murphy and her colleagues.
“This places increased pressure on marine ecosystems through stressors including habitat destruction, overfishing and pollution.”
“Oil spills are one form of environmental pollution that poses both immediate and long-term consequences for marine ecosystems.”
“Large-scale oil spill disasters have been frequently recorded over the past number of decades, including the Exxon Valdez (Alaska, 1989), Sea Empress (Wales, 1996), Prestige (Spain, 2002) and Deepwater Horizon (Gulf of Mexico, 2010).”
“While not as immediately damaging as an acute large-scale leak, persistent or chronic oil pollution can also impact vulnerable marine populations over much greater time scales.”
In their study, the authors collected feathers from Manx shearwaters, a seabird species thought to be at-risk from oil pollution.
They examined the feathers 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 found that really thin oil sheens, between 0.1 and 3 µm in thickness, were enough to have a significant effect on feather structure and impacted waterproofing.
Seabirds exposed to oil are more likely to become waterlogged, cold, and less buoyant, other studies have shown.
“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,” Dr. Murphy said.
“We 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.”
“Even when oil is released in moderate volumes from extraction and transport infrastructure, oil can spread quite quickly across the surface of the sea, and quite a large marine area can be coated by oil in concentrations that can be harmful for seabirds.”
The results were published in the journal Royal Society Open Science.
E. Murphy et al. 2022. Light to intermediate oil sheens increase Manx shearwater feather permeability. R. Soc. open sci 9 (10): 220488; doi: 10.1098/rsos.220488
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