The Seattle Aquarium attracts visitors from all over to the city’s central waterfront. Perched on Pier 60, it has a commanding view of Elliott Bay. It’s also an ideal place to study the tiny bits of plastic that wind up in the water and threaten marine wildlife.
Underneath all the live tanks and colorful exhibits is a world few get to see. You get there by going down a staircase that’s normally reserved for staff.
“We like to say that we're literally knee deep in Elliott Bay ... and now so are you!” quips Erin Meyer, the aquarium’s director of conservation programs and partnerships.
She leads the way into an underground labyrinth of hallways lined with pipes and machinery.
“You're seeing all of our filtration systems. So the water pumps in from Elliott Bay and goes through filtration — sand filters and UV filters that ensure we're not bringing anything in that would harm the animals in our care,” Meyer says.
There are divers getting ready to feed the animals, people preparing the food, even an octopus in a tank in one corner. And then, a little way down the corridor, there's a research lab.
Scientists here have engaged in long-term monitoring of everything from sea otter ecology to Salish Sea ecosystems for nearly three decades. And for about five years now, they have been studying the impacts of microplastics.
“Right now, microplastics are found everywhere — in every species that we have tested," says Lyda Harris, the aquarium’s microplastics fellow.
She recently graduated from the University of Washington with a Ph.D. in biology, looking at how these tiny particles affect the filtration of marine mussels, among other things.
The tiny bits of plastic behave like toxic crackers, carrying pollutants into the guts of organisms that eat them. Harris says they can have negative impacts on immune systems, reproductive rates and longevity.
Research into all of this is currently exploding. But Harris says one of the limitations for field research is how to get the sheer volume of water that's needed for sampling.
“You’ve got to get a boat, you've got to get a pump, all of these things. And so that's where the aquarium is in the perfect location to do that — because we're already taking in huge volumes of water every minute, to circulate through our exhibits,” she says.
Every two weeks, they tap a pipe at the end of one of the long corridors beneath the exhibits and filter out the microplastics in 100 liters. Harris puts on a white cotton lab coat and rolls a special trash can on wheels out from beneath a counter full of microscopes and beakers.
She wheels it down the corridor to a spigot for unfiltered seawater, clears the line briefly, and begins running it through a sterilized metal screen.
“And making sure that all the water is going through the filter,” she says as she carefully positions a bicycle cup holder with the filter beneath the faucet.
It takes nearly a half hour to fill the trash can and filter out the microparticles.
Back in the lab, they process the sample and note the amounts and qualities of the plastics they find. They’re looking for trends that usually correlate with things like rainfall or runoff coming from the Duwamish River nearby.
But Harris says none of that explained a sudden drop off of microplastics in their data on April 10, 2020 – just two weeks after the city shut down because of the pandemic. The number of people visiting Seattle at that time decreased by 81 percent.
“And so that immediately sent off a light bulb. Like, maybe it is the quantity of people actually coming to the city — because we didn't stop necessarily doing laundry. There was no difference in that. The rain didn't stop. The Duwamish outflow didn't stop.”
But scientists know that the clothes we all wear shed synthetic fibers. Harris and her colleagues suspect that was the source of microplastics that disappeared.
“If you've ever looked at your lint in your drying machine, it is usually full, depending on what you're washing. But that same concept comes around when you're just walking,” she says.
The friction when you swing your arms or brush against your clothes releases lint-like bits into the atmosphere.
In fact, the aquarium noticed this phenomenon on site several years ago. Tiny blue fiber particles were showing up in all their samples. They traced them to fleece vests that were worn by staff as uniforms. Those have now been replaced with a cotton blend that doesn’t shed nearly as much, says curator Shawn Larsen, who’s in charge of all the research here.
“So we're not saying everybody has to wear all cotton and all natural fibers. I mean, that's great, but maybe just wear things that don't tend to break apart so easily,” she says.
Larsen says an important area of study is how much microplastics is settling into sediments around the Salish Sea. That’s where crabs and clams and mussels that people like to eat interact with them.
Researchers at the aquarium will be looking closely at data sets pre- and post-pandemic, to see how much of it is coming from people’s clothing.
