Scientists have finally figured out why seabirds eat plastic, although it has no nutritional value. On the contrary, seabirds which swallow plastic have an elevated risk of getting injured, while sometimes they even die.
The Rotting Smell
Plankton usually sticks to any plastic bottle or piece which floats. After breaking down, it starts smelling like rotting seaweed, thus attracting the seagulls or albatross. Based on the statistics, around 90 percent of the seabirds eat plastic, and many of them are more likely to die because some bits remain in their bellies.
According to Matthew Savoca from the University of California, seabirds rely on odors to find food, although they have to travel hundreds of miles. Scientists analyzed the plastic compounds and discovered a chemical, which seabirds usually associated with the rotting carcass of a large fish.
Therefore, these seabirds eat plastic waste because their brains associate it with food. This situation is concerning because plastic pollution rates have been increasing over the past few years with 250 million tons of plastic waste recorded two years ago.
Savoca underlines that these birds are confused, so they don’t know they are eating something very poisonous.
Studying Why Seabirds Eat Plastic
Experts from the University of California conducted a study in which they used mesh bags filled with microbeads and threw them into the sea. After twenty days, they analyzed the chemical signatures on the plastic to see whether they developed any smell which birds could associate with food.
Three samples had a particular chemical smell, called dimethyl sulfide, which birds usually associate with rotting seaweed or boiling cabbage. This chemical compound is usually produced in ocean waters when plankton breaks down.
Unlike humans, seabirds such as shearwaters, petrels, and albatrosses can easily pick up this scent, which they immediately associate with food. Specialists are concerned because the same odor might attract other marine species such as turtles, penguins, and fish.
This is not the first time scientists come across this problem because plastic waste has polluted many water ecosystems across the world. Savoca says that he and his team will double their efforts to raise awareness about this widely-spread problem. Also, they will continue their investigation to develop an efficient strategy to address this issue.
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