When flesh-footed shearwater chicks hatch from their eggs, their parents start working to fill the chicks’ stomachs with as much food as possible.
They do this for about 80 to 90 days, regurgitating squid and fish into their chicks’ mouths. If all goes to plan, the chicks will grow into fledglings with feathers that will help them fly thousands of miles across the ocean. But as the world’s oceans have filled with microplastics — tiny plastic particles that shearwaters can easily mistake for food — fledglings are getting stuffed full of plastic instead of food. The outcome isn’t good, according to experts.
Scientists studying flesh-footed shearwaters (Puffinus carneipes) have long known that plastic consumption can lead to problems like reduced body condition, organ damage, and ultimately an early death. Now, new research in the Journal of Hazardous Materials shows that consumed plastic can also lead to a newly identified disease: a plastic-related fibrosis aptly called “plasticosis.”
While this disease has thus far only been identified in flesh-footed shearwaters, experts say that nearly every organism — including humans — is being impacted by plastic in some way due to its proliferation in our environment and our ever-increasing exposure to it. One expert calls flesh-footed shearwaters the “canary in the coal mine,” forewarning us of what could happen to our own health if plastic production continues to accelerate as predicted.
‘All these pieces of plastic’
Plastic is everywhere. It’s in our clothing; it packages our food and drinks; it flakes off our car tires. Few plastic products can actually be recycled, and most of it ends up in our environment, either directly as microplastics, such as fibers shed from synthetic clothing, or as larger pieces that eventually break down into smaller pieces. This plastic pollutes the land, water and even the air, and ends up in our food, water, and ultimately our bodies. Many plastics contain toxic chemical additives, but plastic can also act as a sponge attracting other toxic substances, endangering any organism that consumes it.
In the oceans alone, scientists suggest there are now about 170 trillion pieces of plastic — and there could be even more in the future as plastic production continues to proliferate. It’s estimated that there are currently about 450 million metric tons of plastic produced each year, and production is projected to double by 2045.
I’m fairly confident there’s not an animal on Earth that hasn’t been exposed to microplastics in some way, which is terrifying.
Jack Rivers-Auty, biologist and immunologist, University of Tasmania
While previous research has looked at the impacts of plastic consumption on wildlife in a lab setting, this new study claims to be the first to “document and quantify plastic-induced fibrosis in wild organisms.”
The research is based on a sample collection of 21 dead flesh-footed fledglings taken from Lord Howe Island, a small, sock-shaped island about 700 kilometers (430 miles) off the coast of Sydney, Australia. The remote island hosts a large breeding colony for the species. While some of the fledglings were found dead, others were humanely euthanised due to “extremely low body mass.” Most of these fledglings had plastic in their stomachs. On average, each bird contained about 30 pieces, but some held up to 200, the study found.
When the researchers analyzed the birds’ proventriculus, a part of the stomach responsible for digestion, they found that most of the birds had scar tissue indicative of plastic-related fibrosis, or plasticosis.
”All these pieces of plastic, they’re creating little injuries within the stomach,” Hayley Charlton-Howard, the lead author and researcher in Adrift Lab, tells Mongabay. “The stomach is trying to repair those injuries by layering it with a level of scar tissue to help it maintain structural integrity while it’s healing. But if the entire stomach is injured, then the entire stomach becomes really, really heavily scarred, and that’s called fibrosis.”
Once a seabird develops plasticosis, its ability to digest and process foods is reduced. The bird could also have trouble deriving nutrients from its food and be unable to fight off infection or parasites. It’s not currently known if shearwaters can survive for long periods of time with this condition.
The researchers also determined that it was plastic itself that was causing this issue, not other sharp objects like large squid beaks or pumice rocks that flesh-footed shearwaters normally eat. While the reasons for this impact needs to be further investigated, Jack Rivers-Auty, study co-author and human biologist and immunologist at the University of Tasmania, says he believes that plastic triggers an inflammatory response due to its chemical composition.
Rivers-Auty says he was also “completely blown away” by how severe and extensive the fibrotic scarring was in response to the plastic and how quickly the scarring took over the stomach. “The scarring was everywhere,” he says.
The researchers say one point of concern is that plasticosis was even present in birds with only a small quantity of plastic in their stomachs.
“It could be that the birds were able to rid themselves of the plastic somehow, so we couldn’t count that, but we could still see the scarring,” Charlton-Howard says. “Or it may be that just one piece of sharp plastic just bouncing around in the stomach can cause that level [of damage]. We just don’t know.”
Therese Karlsson, the science and technical adviser at the International Pollutants Elimination Network (IPEN), who was not involved in the study, says the research is “very important” because it “gives a name to something that has been discussed within the scientific field for a long time.”
“As the authors note, there has been a lot of previous studies indicating that this might be a possibility,” Karlsson tells Mongabay. “So although it is not surprising, it is concerning that we now know that it can happen in the field.”
‘Canary in the coal mine’
While flesh-footed shearwaters seem particularly susceptible to plasticosis due to the high amount of plastic they inadvertently consume, Rivers-Auty says other marine animals might face similar health issues due to plastic consumption — but that most of these conditions simply haven’t been documented yet.
He also says it’s a “very big concern” that flesh-footed shearwaters can apparently develop plasticosis after only consuming a relatively small amount of plastic.
“If we were to say how many seabirds out there had one or two bits and pieces in [their stomachs], it’s so many seabirds. It is a crazy number,” he says.
But it’s not just seabirds. According to one study, about 1,200 marine species are being impacted by plastic.
“I’m fairly confident there’s not an animal on Earth that hasn’t been exposed to microplastics in some way, which is terrifying,” Rivers-Auty says.
Humans also consume plastic. Scientists suggest that we ingest about 5 grams of microplastics each week through the food we eat, the water we drink, and the air we breathe. There’s also evidence of plastic particles present in human blood and placentas.
Rivers-Auty says he’s working on new research that suggests that human bodies would respond to plastic “very similarly” to the way flesh-footed shearwaters respond to plastic, which could result in a comparably dire outcome if humans are exposed to as much plastic as shearwaters. To this end, Rivers-Auty calls the flesh-footed shearwater “the canary in the coal mine,” especially as plastic production and pollution is expected to multiply in the future, further contaminating our already heavily polluted world.
“[Flesh-footed shearwaters] are unusually exposed to an incredibly high amount of plastic, but that helps warn us where everyone else is going to be,” he says. “I don’t know whether it’s 10 years or 500 years, but … we are going to head in that direction to that similar level of microplastics.”
This story was published with permission from Mongabay.com.
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