It’s been nearly 13 years since researchers first discovered the Pacific Trash Vortex, a country-sized mass of plastic debris in the North Pacific Gyre. Since that time, countless boats have come back with anecdotal reports of masses of plastic floating in the sea.

Earlier this week, we had the chance to sit down with two people who voyaged into the gyre this past summer: Mary Crowley, Project KAISEI co-founder and executive director of the

Ocean Voyages Institute and Nick Mallos, a marine scientist with The Ocean

Conservancy. The pair took part in a 20 person, three-week expedition in August on the research vessel Kaisei that took them from San Francisco to San Diego. This is what they found.

One of the most striking things about traveling into the so-called plastic island is that it isn’t much of an island at all, Mallos explains. “It’s more like an archipelago. It would be so much easier if it was all together in a bunch.”

During the expedition, the crew made sure that one person was on the bow

documenting microplastics (plastics that are one inch in diameter or less) at all times. Every time the designated

crewmember found five pieces of microplastic, they would say “tally” over a radio into the boat’s wheelhouse. In eight days of counting, the crew documented 16,089 pieces of microplastic along with 1,800 larger items, including ghost nets that weigh anywhere from 20 to 400 pounds.

“After a while, you get into a routine, the trash becomes commonplace until you look at a GPS and notice you’re 1,000 miles from San Francisco and Hawaii, surrounded by debris. It’s a surreal experience,” Mallos says.

The heaviest concentrations of trash were between 1,200 and 1,900 miles offshore, but Mallos and Crowley first observed trash on the expedition just 500 miles offshore. “We’ve seen everything from toothbrushes to a car fender, and every type of container imaginable,” Crowley says.