This isn’t a non-sequitur so much as the resumption of our long desultory conversation as watch-mates. Emily, who speaks only un petit peu of English, and is still recovering from sea sickness, lies curled up like a cat against the hatchway, while Marcus and I sit in identical rough-weather posture, backs against the high side bulkhead, feet braced against the low side bench. We’ve talked a lot about the First Gulf War, where then-Sgt. Eriksen led a recon squad, and where, splattered with oil droplets and breathing the fumes of the Kuwaiti oil field fires, he saw the savagery of resource war, and began groping toward the environmental activism that would become his career.

We’ve been talking a lot about rafts. He’s built at least seven, from scrap and recyclables, most notably Junk, 18,000 plastic bottles bundled into two pontoons, with a derelict Cessna fuselage as cabin. In the summer of 2008, he and a fellow activist, Joel Paschal, drifted from Los Angeles to Honolulu in 88 days—“pretty much a walking pace”—to publicize the plastic trash issue.

A thousand waves try to topple the Sea Dragon and are crushed—it’s a formidable rough-weather ship, a sea-going 4x4—and the moon drifts toward the horizon, until it’s time to check the trawl, looking for spoor of the garbage patch beast.

Marcus springs up onto the deck to detach its safety line and haul in the Silver Surfer. Its 40-pound bulk comes out streaming seawater, clanging against the hull. Marcus muscles it over the rail and lays it carefully on the deck. At the end of the net is a PVC collection tube that has to be unclamped—my bit of labor—and by the time I’m done Emily has returned. We gather in the cockpit and train our headlamps on a shallow cake pan, eager to see what shakes out. Lots of little fish, battered to a pulp like anchovies from a pizza. “Myctophids,” Eriksen says. “Lantern fish.” The better-preserved resemble miniature gargoyles, an inch or two long, with underslung bulldog jaws. “It’s the greatest migration in the world, the vertical migration. These little guys coming up out of the darkness of the deep by the billions to feed on the surface every night.” And lots of little black flies, Halobates, tiny marine insects that stride upon the surface of the sea feeding on fish eggs. (What a planet, eh? Where you think there’s nothing, there’s always teeming strangeness!) And finally, among unidentifiable hunks of mucous-like stuff, little bright bits of colorful confetti.

(Algalita Marine Research)

Marcus is speaking into a microphone, recording for the BBC, as he pokes around in the pan with surgical tweezers. “We have crossed the western edge of the South Atlantic Subtropical Gyre and have entered the accumulation zone predicted by drift buoy data,” he says. “And as predicted, we are finding plastic.”

That confetti is indeed garbage patch scat. Particulate plastic pollution. Fear in a handful of dust?

The old Hawaiians — beachcombers par excellence— knew something of gyres, and their power to catch and hold. As the oceanographer Curtis Ebbesmeyer writes in his book, Flotsametrics and the Floating World, Hawaiian kings would post sentinels on coastal lookout spots, watching to see what the great current would bring. King Kamehameha, based on the Big Island, was finally able to conquer Oahu and Maui only after a tremendous storm ravaged the coastal forests of the American Northwest. There, some 3,000 miles away from Hawaii, floods uprooted massive spruce and redwoods and swept them out to sea. When these gifts of the gyre eventually arrived, after a journey of some months or years, they made excellent war canoes, far superior to anything that could be fashioned from endemic trees.

The same Hawaiian beaches still receive the dubious bounty of the gyre, these days by the dump truck-ful. One unfortunately positioned spot on the Big Island, known now as Junk Beach, is periodically inundated with plastic trash from the notorious Great Eastern Pacific Garbage Patch. Ebbesmeyer, who coined the phrase “garbage patch” in the 1990s, compares it to “a big animal without a leash.” It sloshes around at the whim of the weather, and when it strays close to land “barfs up” a load of plastic debris. The trash includes the usual suspects—cigarette lighters, toothbrushes, toys, containers of all ilks and sizes—but is mostly chips and shards the size of fingernail clippings, a sort of ersatz sand creating a plasticized beach. Before regular—laborious and expensive—cleanups were arranged, the plastic trash on Junk Beach accumulated in drifts 16 feet deep. The EPGP doesn’t confine its “accidents” to the Big Island, but has made the entire Hawaiian chain, including the most remote and once-pristine islands, its vomitorium. And it has an evil twin, the Western Pacific Garbage Patch, closer to Japan. Combined, the northern Pacific marine dumps have been estimated to be twice the size of the continental United States.

Something so colossal could not escape notice, and indeed NOAA and other scientific orgs have been quietly studying marine debris for decades. But the scope of the problem did escape any real publicity until a wealthy California sailor, Charles Moore, decided to take a shortcut home from Honolulu in 1997. What he saw—ghost nets, five-inch-thick towing ropes, Japanese traffic cones and quarts of American-made crankcase oil, drums of hazardous chemicals, tires, volleyballs, on and on, in chunky windrows and soupy brews—amazed and appalled him. He sailed and motored for 10 days and never saw a clean stretch of sea. Ever since, like the Ancient Mariner, he has exhausted his voice—and much of his fortune—telling the world about it.

(Courtesy Pangaea Exploration)

Moore returned to the patch in 1998 with his ship the Alguita and a crew of volunteers, hauling aboard a ton of debris, and dragging a trawl to look at the smaller stuff. From his trawl results, Moore measured six pounds of plastic particles for every pound of zooplankton. In the patch, the sea was becoming plasticized. In a cosmic irony, mankind had become the medium for transforming millions of years of complex, edible life forms—the zoo- and phytoplankton that became petroleum—into their far simpler, and indigestible, petroleum-based simulacra.

In this shell game, the most visibly defrauded of nature’s citizens has been the albatross, the oversized canary in the plastic pollution coal mine. Unable to resist the floating plastic smorgasbord, adult birds sometimes choke or starve to death with a gullet full of polypropylene. The necropsy of one chick on Midway Island revealed more than 500 plastic bits, including cigarette lighters, shotgun shell casings, toy wheels, and a piece of an airplane marked “VP-101,” which was traced to a navy patrol bomber shot down in 1944.

That 60-year-old World War II souvenir confirmed what was long suspected: Plastic debris in the gyres wasn’t going anywhere but in endless circles. Indeed, all the petroleum-based plastic ever manufactured—the billiard balls of the 1870s, the nylon stockings of the 1930s, every tiddlywink and bit of sandwich wrap—is still somewhere among us.

Plastic doesn’t readily biodegrade, of course. That is one of its great anti-microbial virtues, as well as its curse. It can persist for centuries in landfills, and longer in the sea, scientists believe. Plastic does photodegrade, however. Exposed to sunlight, it loses its useful qualities, its plasticity—becomes stiff and brittle and breaks up into smaller and smaller pieces. Meanwhile, as a typical 2-liter soda bottle made from polyethylene terephthalate (PET) circles the drain, eventually breaking up into bits, it acts as a molecular sponge for whatever poisons it encounters, absorbing “persistent organic pollutants” like PCBs—which are known to cause cancer in lab animals and are probable human carcinogens linked to increased incidence of melanomas, liver cancer, and gall bladder and brain cancer. Many POPs are “lipophilic,” that is, attracted to fatty tissues, but also oily substances such as petroleum-based plastics. Hideshige Takada, a Japanese scientist studying plastic particles from the Western Pacific Garbage Patch, found them to be one million times more toxic than the ambient seawater in which they floated.

All the filter feeders in the sea—from the tiny salps and jellies to the giant baleen whales—may be slurping up these poison pills. Smaller still and more ubiquitous in the sea is plastic dust, which our bobbing PET bottle will one day become. And dust is not the end. Even plastic dust continues to break down, into strings of indestructible synthetic molecules, too small by far for nets of the finest mesh to catch. It is likely that every seabird now has that micro-plastic in it, and every fish. And all of us. The health repercussions of a poisoned food chain seem obvious, but a catastrophe-to-be may brew unseen like cancer before metastasis.

Ebbesmeyer, who became famous late in his career when he tracked a spilled container of 80,000 Nike sneakers, and made “gyres” a household word, is one of the world’s foremost experts on marine debris. By his count there are eight distinct garbage patches in the planet’s seas, all very likely still on the increase, as plastic production continues to balloon—up from 3.4 billion pounds in 1950 to 567 billion pounds in 2012.

“Nobody knows how dangerous they are,” he said of the garbage patches. “We have very little data. And we simply don’t know how to clean the ocean. We are dealing with perhaps the mother of all problems. I think the ocean is totally infected.”

That’s a scary thought. And yet, we’re not much afraid. We’re a bellicose and contentious species rather than a fearful one, and we’re equipped with awesome powers of denial. In that, we may be as fucked as the albatross by our evolutionary limitations. What we are afraid of is losing our jobs and our homes in an economic depression and having to hit the road as hobo hunter-gatherers. And we believe that could very well happen to a lot of us unless more and more consumers keep buying more and more stuff, much of it made of plastic and nearly all of it wrapped in seductive shiny plastic packages.

“We’re adrift on the rapids of consumption,” Charles Moore told me in a phone interview. “We are becoming our products. People are being moronized by an uncritical consumer culture in which there’s no psychological space for change. Growth has become a sacred word, like democracy or motherhood. It’s the paradigm of cancer.”

In 2005, Moore met Marcus when the latter was touring California schools with Bottle Rocket, the small plastic-bottle paddle-craft with which he had recently completed a 7-month descent of the Mississippi River, from its Minnesota source to the Gulf. Impressed with the young maverick scientist, whom he calls “a great educator,” Moore hired Dr. Marcus as director of program development for the Algalita Marine Research Foundation—in effect, as heir to the garbage patch problem. It’s a burden Dr. Marcus bears with cheerful equanimity.

Aboard the Sea Dragon, about 800 miles out and still in the shit weather-wise, we’re all gathered around the oval galley table, which is comically tilted toward starboard. Everyone is gyroscoping some warm beverage with one hand and munching a bit of chocolate from Marcus’s secret stash. After four days of root vegetable soups and pasta it’s a true luxury.

From what he’s seen at sea, Marcus tells us, he agrees with the growing consensus that there’s no way to clean up the existing patches. A Greenpeace study estimated that it would take 68 ships trawling 24 hours a day an entire year to cover 1 percent of the Pacific. They would burn up a tremendous amount of fuel and do more harm than good. “Going after the trash with nets is like standing on top of the Empire State Building with a vaccum cleaner sucking up air pollution,” he says. Reducing litter would help; plastic drives, like the old school paper drives, with economic incentives to corral plastic waste, would do some good. But not nearly enough.

“There’s no post-consumer solution,” Marcus says. “The answer is to stop the source.”