Scientists are combing the waters in Canada's Arctic searching for pieces of plastic so tiny that, in some cases, they can't be seen with the naked eye.
"We know microplastics are an issue around the world, but we really don't know to what extent, if at all, they are an issue in the Arctic," said Eric Solomon, director of Arctic programs at the Vancouver Aquarium Marine Science Centre, who's part of what he says is the largest study so far on microplastics in Canada's Arctic.
"Obviously, hopefully we are not going to see much at all. It's far less densely populated," said Solomon.
He added that microplastics have been discovered in southern lakes, rivers and oceans around the world, and in Arctic sea ice.
But when it comes to sensitive Arctic ecosystems, Solomon said, "something so small, in this case, could have a significant impact," though it's not clear yet what that impact could be.
Cosmetics, household waste
Microplastics are less than five millimetres in size. Some are manufactured specifically for cosmetics, while others come from bits of polymer that detach from clothing like fleece when it's washed. Still more comes from household waste — and virtually all plastic — that ends up breaking down in lakes and oceans.
Since July, researchers with the Vancouver Aquarium and Department of Fisheries and Oceans staff have been traversing four Arctic regions on board a Russian scientific icebreaker and two Canadian Coast Guard ships.
They plan to return to the same regions over the next two years, and hope to have preliminary results available as early as January 2017.
A threat to the food chain
Plastics are a problem for a number of reasons.
"One is they tend to entangle things, another is that things eat them," Solomon said.
"When an animal eats plastic it fills their stomachs, makes them feel full, satisfied, so they don't eat any more and they can die as a result of that."
He says any threat to one species is a threat to the food chain.
"Arctic cod is a really important species in the Arctic because there aren't that many fish that play that role in the food chain there," says Solomon, noting that seals rely heavily on Arctic cod.
"Microplastic are increasingly seen as a conservation threat," says Peter Ross, director of ocean pollution research at the Vancouver Aquarium and the principal investigator on the research project.
"We're worried about their impacts on invertebrates, on fish. We are worried to a certain degree about microplastics getting into seafood for human communities."
Ross's study of zooplankton off the coast of British Columbia was the first in the world to demonstrate creatures at the bottom of the ocean's food chain are "readily" consuming microplastics.
"One in every 20 zooplankton that we sampled in the northeastern Pacific had ingested pieces of plastic both fibres and fragments," he said.
"So that signalled the emergence of a troubling concern, that smaller creatures at the bottom of the food chain may be confusing these items as food, just as sea turtles have long been seen to be mistaking plastic bags for jellyfish."
Ross says researchers are a long way from understanding how microplastics could impact human health.
Even with the likelihood microplastics won't be widespread in the Arctic, Ross is concerned about the health and the well-being of Inuit.
"There's a strong attachment to country food or traditional foods in the Arctic and the Inuit rely very heavily on marine food webs, so I think we owe it to ourselves, our Inuit partners, to better track microplastics as well as the other pollutants we find in the Arctic."