Scientists are now one step closer to figuring out why certain species of marine creatures are attracted to plastic debris floating in the ocean.
A team of scientists from the University of California has discovered that the plastic debris floating around in the ocean release a certain chemical in the air which is picked up by the creatures, tricking them into believing that the plastic debris is actually food.
The study, which was published on the 9th of November, in the journal Science Advances, reveals that the rate of plastic debris ingestion is more predominant is some species of marine birds, than in others. As a result, tube-nosed birds, like the albatross or the petrel, are more likely to confuse plastic bags for food than others.
To determine what truly drives marine birds to mistake plastic debris for edible food, the scientists conducting the study analyzed in depth how the birds detect food using their olfactory senses.
To this end, they put together a most unusual experiment. The team crafted three large beads made from the most common types of plastic and placed them in special meshes.
After that, they carefully planted the bags into the ocean and returned after three weeks to recover them. The team then took the retrieved bags to Department of Viticulture and Enology from UC Davis, where chemist Susan Ebeler analyzed the chemical properties of the bags.
Her analysis indicated that the bags emanated a compound called DMS (dimethyl sulfide), a sulfur-based compound which is usually released by some species of algae when they are eaten by various predatorial fish species.
Matthew Savoca, the lead author of the study, explains why the birds are attracted to this unusual compound. The scientists declared that when fish species such as the krill prey upon algae, they eliminate this compound, which, in turn, is picked up by marine birds.
Savoca also added that the birds do no necessarily associate DMS with food, but rather a hint that there’s food to be eaten in a specific area. With Savoca’s explanation, the picture become clearer: confusing the DMS in plastic debris with their usual feeding cue, the marine birds swoop in for the kill, only to find plastic debris.
This results of this study can be used in order to come up with a way to deter marine bird species from eating plastic debris.
Image source: Wikipedia