Presence of Oil on Water Surface Could Be Detrimental to Seabirds' Feathers [Study]

A University College Cork (UCC) study discovered that tiny quantities of crude oil on the surface of the ocean, only around one percent the thickness of a hair, can harm seabird feathers.

Scientists from the Marine Ecology Group at UCC in Ireland gathered feathers from Manx shearwaters, a seabird species considered to be threatened by oil contamination. These researchers compared the feathers to determine how quickly the water would move through after being exposed to increasing quantities of oil. Feathers have also been examined under high-powered microscopes to investigate structural alterations caused by pollution.

The result revealed that incredibly small oil sheens with thicknesses ranging from 0.1 to 3 micrometers had a massive impact on feather structure and waterproofing. Similar studies have revealed that seabirds exposed to oil are more apt to get wet, chilly, and much less buoyant.

The Crude Oil Spreaded in the Sea

Based on the latest study conducted by the National Academies National Research Council, nearly 85 percent of the 29 million gallons of petroleum that enter North American ocean waters each year as a result of human activities comes from land-based runoff, polluted rivers, airplanes, and small boats and jet skis while less than 8 percent comes from a tanker or pipeline spills. Crude oil and exploitation account for only 3% of all petroleum entering the sea. Another 47 million gallons naturally leak into the water from the bottom.

Moreover, due to disasters such as the Exxon Valdez and Sea Empress incidents, vast quantities of unrefined oil (crude oil) have been poured into oceans. The substance is also frequently discharged into the environment in small amounts as a result of extraction and transportation operations. Oil contamination is a dangerous concern to many highly endangered seabird species.

(Photo : Jamie Darby, School of Biological Earth and Environmental Science, UCC)
Manx shearwater in flight over the Celtic Sea. Manx shearwaters are a seabird species at risk from oil pollution, due to spending most of their lives at sea, and much of that time on the water surface.

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The Oil Presence Effect of Seabirds' Barbs

"Chronic small-scale oil problems are usually ignored in the marine ecosystem, despite being shown to have serious repercussions for the fitness and preservation of seabirds," stated Emma Murphy, the study's principal researcher. "These researchers analyzed one species, but the results can be lengthened to other species that rely on waterproofing to remain healthy when at sea for prolonged periods," Murphy added.

However, when oil is spilled in small amounts from exploitation and transportation facilities, it may travel swiftly throughout the water's surface, coating a huge region of the water in quantities that are toxic to seabirds.

It was expected that higher levels of oil exposure would have a bigger influence on the functional organization structure of feathers. Yet, this research revealed that trace levels of oil can destroy the feather's barrier against water intrusion.

Surface tension is generated between the oil and the water under oily substance conditions, where barbs-part of the bird's wings. Barbules persist more evenly distributed due to the balance of adhesion and repulsion forces among both adjacent barbs produced by the heavy layer of oil, and much more pressure is compelled for water to saturate thru the barbs, according to the research published at Royal Society Publishing.