Julie Masura is heading out into Tacoma’s Commencement Bay in search of plastic.
She’s a researcher with the Center for Urban Waters, where members of various academic and government organizations come together to study water pollution and human-environment interactions in Puget Sound. Getting down to the particulars though: Masura is looking for microplastics, which are defined as plastic particles smaller than 5 millimeters.
The boat slows down to about 4 miles per hour and Masura drops over the side a device that looks like the lovechild of a manta ray and a model airplane. It’s got a wingspan of about four and a half feet and a gaping mouth that hovers right at the surface. Water rushes through the mouth as the boat moves along and gets sifted through a long net floating behind it.
After 15 minutes, Masura pulls the net back into the boat to collect the sample. In the bottom of the net tiny bits of brightly colored plastic pepper the usual organic debris you’ll find floating in the water column.
Masura and her team have been conducting these microplastic sampling trips every month for a year and a half now and today’s results, she says, are consistent.
“Unfortunately we’ve found plastic in all of our samples that we’ve taken from all over the Puget Sound and the west coast of Vancouver Island,” she says.
Microplastics have turned up in samples taken from every ocean on the planet and species from the bottom to the top of the marine food chain have been found to ingest these tiny particles – from sharks, seabirds and turtles to filter-feeders and krill.
Mark Browne studies microplastics at the University College in Dublin, Ireland and has found that with plastic anyway, it could be the little things that kill.
“What the research that we’ve done shows is that over 65 percent of the plastic on beaches, in terms of abundance, is actually microscopic plastic debris,” he says.
So in theory, if you went out and blindly collected 100 pieces of plastic, of all sizes, 65 of those pieces would be too small for us to see - but for krill or filter feeders - it looks like food.
OK. So marine animals are ingesting plastic. So what? Shouldn’t those tiny pieces just go in one end and out the other? Not exactly, says Browne. Some research on mussels showed that these filter feeders not only accumulate plastic in their gut, but those particles make their way into the circulatory system where they’re stored in cells for periods of up to 50 days.
And that, Brown says, could be a problem.
“If we’re consuming these organisms as part of our diet or other organisms that also consume them … what are the ramifications of transferring plastics that are likely to have chemicals absorbed onto them, therefore transferring from the environment into the animal and then being stored there?” he says.
Ask the parents of any two year old and they’ll tell you eating plastic probably isn’t a great idea. Research on lab animals has shown many plastic products contain chemicals that can be carcinogenic, neurotoxic or disruptive to the body’s hormonal messaging system.
But when it comes to figuring out what exposure to microplastics might mean for sea life and human health, there are some gaps in our knowledge, says Joel Baker, science director at the Center for Urban Waters in Tacoma.
“We really need to understand more details about the effects of the microplastics on marine organisms but also more clearly understand what the future holds in terms of likely impacts,” he says.
Baker says microplastics may not measure up to climate change, overfishing or ocean acidification in terms of threats to the world’s oceans.
But, he warns, “if we continue to build up the levels of plastics in any of these systems it’s conceivable that eventually we’ll get to the point where it’s causing problems.”
The impacts of microplastics in marine ecosystems may not be entirely clear yet, but Baker says now is the time to do the research that will lay the groundwork for dealing with this pervasive form of pollution in the future.
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