When bottles and bags are cast out to sea, the debris never truly goes away — it just gets smaller. And these plastic particles, called microplastics, are ready meals for fish and birds.
The vast majority of debris in the ocean — about 75 percent of it — is made of plastic. It can consist of anything from plastic bottles to packaging materials, but whatever form it takes, it doesn't go away easily.
While plastic may break down into smaller and smaller pieces, some as small as grains of sand, these pieces are never truly biodegradable. The plastic bits, some small enough that they're called microplastics, threaten marine life like fish and birds, explains Richard Thompson, a professor of marine biology at Plymouth University in the U.K.
"The smaller the piece of debris, the more accessible it is — and the wider the range of creatures that could potentially eat it," says Thompson, who talked with NPR's Melissa Block about his research on the effects of these tiny particles.
Listen to Thomson's audio interview here: