SCOTT SIMON, HOST:
Over and over, in the world's oceans, baby seabirds often mistake bits of trash for food. New research in the journal Science Advances shows that ingesting plastic can harm them in unseen ways. Here's NPR's Jonathan Lambert.
JONATHAN LAMBERT, BYLINE: The main way biologist Alix de Jersey tells how much plastic a baby seabird has eaten is by feeling its stomach.
ALIX DE JERSEY: When birds are really highly plastic impacted, we can actually feel the plastic rubbing beneath our fingers.
LAMBERT: But from the outside, such birds seem healthy. Much of what scientists know about how plastics harm birds comes from studying dead ones. But de Jersey, of the University of Tasmania in Australia, wanted to study some live birds.
DE JERSEY: We were really wanting to unpack, you know, what is it like for these birds that are living with just a few pieces of plastic within their stomach, and what are the health consequences of that?
LAMBERT: To do that, she and her colleagues turned to blood, specifically the blood of 31 sable shearwater chicks caught on Lord Howe Island. They're about the size of a seagull. And just before they were set to depart on a year's-long migration, the team got the birds to vomit and drew blood from low- and high-plastic birds.
DE JERSEY: Each high-plastic bird averaged about a teaspoon to a teaspoon of half of plastic within their stomach. We were hoping for no plastic birds, but they were actually quite challenging to find on the island.
LAMBERT: The team looked for patterns of protein levels that are associated with organ dysfunction and health problems in humans and mice. They first found signs of dysfunction in the liver and kidneys.
DE JERSEY: It's not a surprise. We know that the microplastics are being filtered by these filtering organs.
LAMBERT: It also seemed that plastic was breaking down the stomach lining of the birds.
DE JERSEY: If you've got big chunks of plastic rubbing around in your belly, you're going to see perforation of that stomach lining.
LAMBERT: There were even signs of neurodegeneration.
DE JERSEY: We weren't expecting that at all.
LAMBERT: De Jersey doesn't know how plastics caused these changes, though one idea is that microplastics could be essentially shredding the cells and penetrating organs. It's also unclear when or even whether these protein changes will cause more visible harm. To find out, she'll have to wait and see if the chicks return to the island after several years at sea. Jonathan Lambert, NPR News.
(SOUNDBITE OF HERMANOS GUTIERREZ'S "SUELTALO") Transcript provided by NPR, Copyright NPR.
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