Voyage to the Plastic Vortex

Scripps Researchers Explore Garbage Patch During Eye-opening Expedition

It's the middle of oceanic nowhere. No luxury cruise boats. No fishing vessels. Not even the occasional cargo ship. Other than the intermittent flying fish skimming over and then plopping back into the water, it's eerily silent. It's here that the azure seawater and breathtaking sunrises give the impression that the North Pacific Ocean Gyre is a thing of perfection.

But science is telling a different story. For three weeks in August, a group of graduate student researchers from Scripps Institution of Oceanography at UC San Diego traveled a thousand miles west of California to the "Great Pacific Garbage Patch" to investigate a convergence zone of plastic and other marine debris.

While data from the Scripps Environmental Accumulation of Plastic Expedition, or SEAPLEX, is currently being processed and evaluated, the gravity of the situation has been confirmed: Human-produced debris was evident in most every jarful of ocean water sampled in the gyre.

SEAPLEX researchers, supported by UC Ship Funds and collaborator Project Kaisei, departed on the Scripps research vessel New Horizon on August 2 armed with knowledge gained from previous trips headed by the Algalita Marine Research Foundation. Scripps team members were not exactly sure what they would encounter. At minimum, their data would help scientists develop a baseline of information to better characterize the scope of the debris problem at the gyre.

"We were targeting the worst-cases scenarios of where the plastic is accumulating," said Miriam Goldstein, SEAPLEX chief scientist and a third-year Scripps graduate student. "We were looking to assess the impacts the debris may have on the biological communities in the gyre."

En route, the first days were spent testing equipment and collecting an array of data from the California Current, a major current that flows south along North America, in order to compare the state of ocean water and marine organisms there with those within the gyre.

By the fifth day of the expedition, the plastic came. At first it was tiny flecks. But not long afterwards SEAPLEX debris watchers on the top deck of New Horizon began consistently reporting sightings of large pieces of marine debris: a shampoo bottle, a piece of a bucket, part of a laundry basket, the sole of a shoe, several ropes, and on and on. Reports of both big and small pieces grew from dozens to hundreds.

Once within the gyre, as winds and waves dissipated, the researchers collected water samples at a feverish pace at several locations and from layers ranging from the sea surface to the middle of the ocean water column. They extracted copious amounts of plastic consistently from sea surface extractions, but even some deep water samples yielded plastic specks.

A small boat deployed off New Horizon gave the scientists freedom to study the gyre water up close and to examine the problem in large and small forms. In certain sectors, broken-down plastic flecks peppered the water like confetti. In another area they encountered a snarled mass of debris--estimated at more than 12 feet in length--featuring wound-up ghost fishing nets and ropes, tarp, and various plastic pieces, big and small.

"The thing that has shocked me and the rest of the science party is just how much plastic is out there," said Goldstein. "It was very different than we expected because we thought it would be hard to find and detect high plastic areas. But we easily found plastic because there is a lot out there."

Crabs, fish eggs, and other marine creatures inhabited many of the plastic pieces, giving SEAPLEX researchers vital samples to begin to understand how the gyre's ecological structure is being affected by human-generated debris.

Jim Leichter, a Scripps professor of biological oceanography and faculty advisor on the voyage, said two things struck him immediately about the plastic debris field: the very large scale of space affected--an area of hundreds of square kilometers--and the small size of most of the particles, many of which are comparable in size to the planktonic organisms in the system.

"Since we entered the gyre, we have found plastic in more than 100 consecutive surface net tows over a distance of nearly 1,000 nautical miles," said Leichter. "There appears to be an almost continuous stream of plastic on the surface and the vast majority of the particles are a few millimeters to less than a centimeter in size. There is a great deal we do not yet know about this issue, but the sheer number of plastic particles and the area affected is striking."

One after another, the student researchers independently expressed enthusiasm about the evidence collected, but deep concern about the human-caused scope of the problem they witnessed first hand.

"I'm a little disheartened about all (the debris) we are seeing, but it is the reason we came out here," said Darcy Taniguchi, a member of SEAPLEX and Scripps graduate student. "It makes things a little more concrete to put numbers on it and realize that yes, it's out here and there's enough of it in the very diluted ocean that we can still see it in really long stretches continuously."

Taniguchi said the samples she and the other SEAPLEX researchers obtained will help them figure out what's happening in the gyre and, "what effect all this plastic pollution has done, if anything."

—Mario C. Aguilera

September/October 2009