The dire effects of ingesting plastic debris become clear
It’s well known that many species of seabirds ingest huge amounts of plastic while foraging out at sea, but a recent study has discovered the plastic they consume is actually responsible for a newly described internal disorder — plasticosis.
A decade ago, the world was shocked when research revealed that Flesh-footed Shearwaters on Lord Howe Island — generally considered a rather pristine environment — had ingested unexpectedly high amounts of plastic as they foraged.
Although there are several theories about why seabirds eat plastic at sea, these theories generally agree that the seabirds are attracted to it as they mistake it for their prey. Once it’s been eaten, pieces of plastic remain in the digestive tract of the bird, as plastic is — of course — undigestable, and it’s also difficult to regurgitate. This is known to cause starvation among seabirds, as it becomes increasingly difficult to feed effectively when they are full of bits of plastic debris.
However, the recent study, conducted on Lord Howe Island’s Flesh-footed Shearwaters, has shown that it’s much worse than that. A team of scientists from institutions across the world under the banner of ‘Adrift Lab’ found that the plastic ingested by these shearwaters has spawned a previously unknown disease. Now known as plasticosis, it is caused by sharp pieces of plastic continually digging in to the bird’s digestive tract, which inflames the delicate internal tissues.
Under normal circumstances, occasional damage would heal naturally, but over time, when the tissue is repeatedly punctured and inflamed, the wound is prevented from healing and the scarring becomes permanent. Further ingestion of plastic debris results in excessive amounts of scar tissue forming, which reduces the flexibility of the internal tissues of the digestive tract and causes changes to their structure, making it difficult to digest real food when it is eaten. This results in profound effects on the bird’s rate of growth and, ultimately, its survival.
Plasticosis is difficult to detect without internal examination, as birds suffering from the ailment often appear outwardly healthy. Without a much wider investigation, the global extent of the disease is unknown, as this is just the tip of the proverbial iceberg, and logically it will almost certainly afflict a huge range of marine lifeforms right around the world as, alarmingly, over a thousand marine species are known to ingest plastic debris.
Birdlife Australia Newsdesk e-News April 2003