What happens to the plastic in the ocean?

27 January 2015

Part of the show Lifting the lid on Plastic

OCEAN-SEA

Credit:

CC0, via Pixabay

Question

“I recycle in the hopes of preventing the plastic from pelletizing in the oceans.” And then she wants to point out that labelling isn’t at all user friendly on different types of plastics, but what is the process by which these plastic breakdown in the ocean and then turn into these micropellets which then can damage animals?

Answer

Charles - Well, there's three basic processes. One is photo degradation where UV rays crosslink the molecules and make them brittle so that it breaks apart very readily in wave motion. Another one is the extraction of the plasticizers that soften and make the material flexible by the ocean itself like the seawater itself is very good at extracting the plasticizers that make the plastic supple. And the third mechanism that I'm thinking is much more prominent than has been given a role in this process is the biting of the material by sea creatures. Practically, every piece of larger plastic that we pull up out of the ocean has the edges nipped off. I think a lot of these small fragments are created by munching the edges of plastic as it floats in the ocean.