Photographs of strangled sea birds and suffocated sea turtles have widely publicized what happens when plastic gets into the ocean.
But what happens when that water bottle or plastic bag breaks down into smaller and smaller pieces?
Julie Masura: “Here we go!”
Julie Masura is heading out into Tacoma’s Commencement Bay. She’s a researcher with the Center for Urban Waters here and today she’s looking for plastic…but not the kind you can see from the sides of the boat.
Julie Masura: “We are going to be sampling microplastics and microplastics are defined as anything that ranges from the width of a pencil and the width of a pin is the range of sizes that we’re interested in.”
The boat slows down to about 4 miles per hour and she drops a device that looks like the lovechild of a manta ray and a model airplane over the side. 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.
Julie Masura: “Alright”
Water dripping on the deck, clunking.
“Let’s see what we got”
Julie Masura: “So right now I am getting all the goop out of the sampling cup and getting my jeans all nice and wet as I kneel here. Wow, look at that. Now that you can see all those white bits and the blue bits and the transparent bits, that’s all microplastics.”
Masura and her team have been conducting these microplastic sampling trips every month for a year and a half now and today’s results are consistent.
Julie Masura: “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.”
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.
Mark Browne: “What the research that we’ve done shows is that over 65% of the plastic on beaches, in terms of abundance, is actually microscopic plastic debris.”
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.
Mark Browne: “So it’s more biologically available to those organisms. The big bits aren’t, unless you’ve got a huge gob.”
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.
Mark Browne: “So this represents a significant problem because 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?”
Ask the parent 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, Joel Baker – who is the science director at the Center for Urban Waters in Tacoma - says there are some gaps in our knowledge.
Joel Baker: “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.”
Baker says microplastics may not measure up to climate change, overfishing or ocean acidification in terms of threats to the world’s oceans but…
Joel Baker: “…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.