SYDNEY: They might be at the bottom of the food chain, but krill could prove to be a secret weapon in the fight against the growing threat of plastic pollution in the world’s oceans.

New research on Friday showed the tiny zooplankton are capable of digesting microplastics — under five millimetres (0.2 inches) — before excreting them back into the environment in an even smaller form.

Study author Amanda Dawson stumbled on the finding while working on a project involving microbeads — polyethylene plastic often used in cosmetics such as face scrubs — at the Australian Antarctic Division’s krill aquarium to check the toxic effects of pollution.

“We realised that krill actually break up plastic, it was amazing,” the researcher from Australia’s Griffith University said.

“It’s difficult to know exactly what the implications of this could be, but the theory is that because plastics in the ocean are already degraded and more fragile, they would be even easier for krill to break up.” The problem of plastic pollution is widespread, and rapidly getting worse.

Every year, more than eight million tons ends up in the ocean, costing billions of dollars in damage to marine ecosystems and killing an estimated one million sea birds, 100,000 sea mammals and untold numbers of fish, studies have shown.

UN Secretary General Antonio Guterres last year cited one study that showed plastic could outweigh fish in 2050 if nothing was done.

Australian Antarctic Division krill biologist and study co-author So Kawaguchi said this was the first time scientists had examined microplastics digested by the crustaceans.

Published in Dawn, March 10th, 2018