A world-first study by Australian researchers has found that krill can digest certain forms of microplastic into smaller fragments. The study observed that Antarctic krill, Euphausia superba, were able to break down 31.5 micron polyethylene balls into fragments less than one micron in diameter. Within five days in a plastic-free environment, all plastics had left the krills’ systems, meaning that the microplastics won’t accumulate in animals further up in the food chain.
Although the krill further breakdown the microplastics, it does not degrade them, leading to the creation of a new source of plastic pollution known as nanoplastics. These are interacting with ecosystems in ways which are not fully understood, potentially causing significant damage, as they are able to penetrate membranes and enter the bloodstream. As these nanoplastic fragments are too small to be picked up by most ocean plastic surveys, it could mean the ocean is much more polluted than currently assumed.