Credit: Jack Rivers-Auty
Researchers performed a procedure called stomach flushing to collect plastic pieces ingested by shearwater chicks.
Seabirds and other marine creatures are particularly vulnerable to plastic pollution. They mistake plastic debris floating in the ocean for food. Researchers recently coined the term ‘plasticosis,’ a condition that’s causing seabirds’ digestive tracts to become scarred from eating pieces of plastic.
Now the same team, along with their colleagues, have found signs of dementia-like brain damage, kidney and liver dysfunction, and disruptions to the stomach lining of sable shearwater chicks (Sci. Adv. 2025, DOI: 10.1126/sciadv.ads0834).
Formerly known as the flesh-footed shearwater, these seabirds, found in the Indian and Pacific Oceans, are considered “near threatened” by the International Union for Conservation of Nature. One reason suspected for their decline is plastic consumption by chicks and adults.
“It was absolutely shocking to see these signals of dementia because these birds are less than 100 days old, and they live up to 37 years,” says study coauthor Jack Rivers-Auty, a lecturer at the University of Tasmania. “And we’re talking about a median of a teaspoon and a half of plastic in the stomach of these birds."
Credit: Justin Gilligan
Researchers retrieved 403 pieces of plastic from a single 90-day-old sable shearwater chick.
Rivers-Auty and his team used a mass spectrometry–based proteomics approach to identify disease markers in the blood of these plastic-ingesting birds. In 2023, on Australia’s Lord Howe Island, they identified 31 shearwater chicks that were comparable in their physical attributes, such as weight and wing and beak length. “In every way, these birds appeared healthy,” Rivers-Auty says. But their stomach contents revealed individuals with relatively high amounts of visible plastic and birds that had eaten less plastic.
Comparing the two groups, the researchers found significant differences in the levels of 202 of 745 plasma proteins detected in the birds’ blood. For example, in shearwaters with more plastic, the scientists found high levels of intracellular proteins, including glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase. This finding suggested that “the plastic was inducing cells to pop,” Rivers-Auty says, and that “all these proteins that should be inside of cells were now outside.”
Credit: Alix de Jersey
A 90-day-old sable shearwater fledgling emerges from its burrow on Australia’s Lord Howe Island. It’ll spend about 5 years at sea before returning to the island to breed.
His team also found low levels of albumin—a protein made by the liver—in the blood of birds with more plastic in their stomachs. The low levels may indicate liver or kidney dysfunction. These birds also had significantly decreased levels of a protein called brain-derived neurotrophic factor (BDNF), which plays a key role in the growth, survival, and functioning of neurons and affects memory and learning.
As young birds, “they need to mentally encode where their island is, where their burrow is, and remember it for 5 years while they go fishing off the coast of Japan and then have to return on that exact [approximately 10,000 km] journey,” Rivers-Auty says. “They might forget.” A drop in BDNF levels could also mess with the birds’ ability to discern each other’s songs, the team suggests.
It's alarming, says Laura Dagley, head of the proteomics facility at Australia’s Walter and Eliza Hall Institute of Medical Research who wasn’t involved in the study. But “it [the suspected consequences] is really something that has to be followed on and really measured.”
For now, it’s unclear whether these shearwater chicks remain affected as adults. But the researchers are testing the blood of other adult sable shearwaters in the same colony to assess the effects of plastic exposure.
Meanwhile, Shane Burgess, a veterinarian and scientist with expertise in proteomics at the University of Arizona who wasn’t involved in the research, says that the study positions the shearwaters as “sentinel species,” warning us of emerging environmental and health hazards.
Chemical & Engineering News
ISSN 0009-2347
Copyright © 2025 American Chemical Society
You might also like...
He and Dagley hope that future studies will involve similar work on other bird species also experiencing plastic pollution to see if the findings hold.