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Diving for Microplastics Pollution

My organization Adventurers and Scientists for Conservation partnered with Nat Geo powerhouse Pristine Seas this year to expand our microplastics research below the ocean surface. Here, ASC’s Emily Stifler Wolfe talks more about the partnership, and our surprising initial results. 

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Adventurers and Scientists for Conservation has found microplastics pollution in nearly every liter of ocean surface water we’ve sampled in our two-plus years of research.

And we’ve sampled some remote places. ASC volunteers have gathered water from locations including Antarctica, the Denmark Strait between Iceland and Greenland, the Falkland Islands, and the middle of the Pacific and Atlantic oceans.

Microplastic fibers as photographed under a microscope by ASC scientist Abby Barrows. This sample is from the ASC sailboat, Khujada, gathered mid-ocean during the Atlantic Rally for Sailors. (Photo by Abby Barrows)

Using an innovative sampling technique, we’ve found much higher concentrations of plastics at the surface level than most other studies, likely due to the use of very fine filters, which allow us to find particles down to .5 microns, or 0.0005 millimeters. Although most of these plastics are so small they’re invisible to the naked eye, they can still cause harm to ecosystems: Research has shown that toxins including DDT and BPA adhere to the particles, which are often ingested by aquatic life and corals. We know that the toxins biomagnify as the move up the food chain; however, we’re just beginning to understand the scope and the ecological impacts of large-scale microplastics pollution.

ASC is working to fill some of these gaps in information. Our goals are to compile the largest, most complete dataset on microplastic pollution, and to distribute that information, leveraging it to ensure that lawmakers, corporations and the public are able to make informed decisions and influence change. We already have more than 1,000 marine samples, and expanded our research to freshwater this spring.

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Now, with help from Pristine Seas, we’ve been able to look below the ocean surface. In September 2014, the team collected 22 samples as part of a Pristine Seas expedition to Palau—half on the surface and the rest at three and five meters below the surface. They were the first divers for the ASC Microplastics Project.

Our lead microplastics researcher Abby Barrows found that the Pristine Seas: Palau samples gathered from below the surface contained a higher number of microplastics—263 pieces in total—compared to 191 from the surface samples.

“We go to the most remote places in the ocean and even there, we have found great abundance of microplastics in sea water,” Barows said. “Thanks to our collaboration with ASC, together we have been able to assess part of the global footprint of modern human society.”

ASC also received a set of samples from Cape Wrangell, Alaska, around the same time as the Palau samples. There, volunteer John Whittier collected five samples at the surface, and then used specialized equipment to sample at 92, 105 and 173 meters depth. Again, the samples collected below the surface held a higher number of plastics.

“Seeing the high number of microplastics throughout the water column was flooring,” Barrows said. “It’s not just a surface and bottom sediment issue. This is a serious pollution problem from the very surface all the way down to the depths.”

Barrows explains that the reason particles are suspended at different depths is due to influences of varying plastic buoyancy and density, as well as bacterial or algal growth directly on the plastic pieces.

Manu_San_Felix_1214Manu_San_Felix_1017MSF_9640At ASC, we’re looking forward to receiving the results from Pristine Seas’ most recent ASC sampling in the southern Seychelles, and to learning about their upcoming trip to Lancaster Sound, near Baffin Bay, Canada.

Although it is sparsely populated, this area may be polluted due to ocean currents coming from more developed areas, Barrows said, noting that she found an average of 10 pieces of microplastics per liter from the ASC Shifting Ice-Changing Tides expedition between Iceland and Greenland.

ASC is now looking to engage other divers, in order to gain a better understanding of microplastics distribution worldwide.

“Were these just pockets [in Palau and Alaska], or is it just as big an issue at depth in all the world’s major oceans?” Barrows asks, explaining that knowledge will help motivate cultural shifts in how we use plastic. “Having results from throughout the world’s oceans enables us not to point fingers, but to show that this is an issue that needs to be shouldered locally and globally.”

Learn more about the ASC Microplastics Project at www.adventurescience.org/microplastics.

Learn more about National Geographic’s Pristine Seas.