Tiny bits of broken-down plastic smaller than a fraction of a grain of rice are turning up everywhere in oceans, from the water to the guts of fish and the poop of sea otters and giant killer whales.
Yet little is known about the effects of these "microplastics" on sea creatures or humans.
"It's such a huge endeavor to know how bad it is," said Shawn Larson, curator of conservation research at the Seattle Aquarium. "We're just starting to get a finger on the pulse."
"We're first going to prioritise who it is that we're concerned about protecting: what organisms, what endangered species, what regions. And that will help us hone in ... and determine the data we need to do a risk assessment."
"Everything, as it goes up toward the top, it just gets more and more and the umbrella gets wider. And who sits at the top of the food chain? We do. That's why these researchers are coming together, because this is a growing problem, and we need to understand those effects."