By analyzing samples taken during a record-setting swim from Hawaii to California, scientists have discovered the Great Pacific Garbage Patch—the biggest cluster of floating marine debris in the world—is teeming with life. Creatures that float near the surface, such as blue sea dragons and by-the-wind sailor jellies, suffuse the rubbish in much greater quantities than previously realized.
The new findings, detailed in the journal PLOS Biology, suggest that parts of the ocean often dismissed as repositories of trash may be overlooked biological hotspots. "These places that we've been calling garbage patches are really important ecosystems that we know very little about," says study senior author Rebecca Helm, a marine biologist at Georgetown University in Washington, D.C. "We're so focused on the plastic; we've completely missed these ecosystems that were sort of hiding in plain sight."
The life found in the patch is mostly neuston, or surface-dwelling aquatic organisms. Many are colored blue on top and white beneath, countershading that likely provides camouflage from predators above and below, Helm says.
Examples include flower-shaped blue button jellies that "shimmer and pulse, like stars," she recalled on Twitter, and violet snails, which "keep from drowning by making a life raft of snail slime." The team also found blue sea dragons, a predator of the jellyfish-like man o’ war. A type of sea slug, the dragon steals the man o' war's stinging cells, "covering their bodies in armor made from the weapons of their vanquished prey," Helm noted.
This abundance of life "is really quite remarkable, not only because the plastic is generally considered not to be very beneficial for ocean life, but also because nutrient concentrations are very low in the North Pacific Garbage Patch," says A.W. Omta, an oceanographer at Case Western Reserve University in Cleveland, who did not take part in this study.
For now, it is not clear how this intermixing of debris and life may impact the ecosystems of the rest of the ocean. Previous research has shown that sea turtles, seabirds, fish, and other animals sometimes have trash mixed with neuston in their guts, suggesting the animals are inadvertently eating the waste along with the prey.
The life in the Great Pacific Garbage Patch floats like plastic and probably got concentrated in the area by the same currents that deposited the trash. Although scientists learned about the patch because of the plastic buildup there, "it's likely been an ecosystem a very long time—thousands and possibly millions of years, long before plastic," Helm says. "We just didn't see it."
A swim for the record books
Earth’s oceans have five primary gyres, vortexes where multiple currents meet. The largest of these contains the Great Pacific Garbage Patch, where swirling waters have concentrated vast amounts of waste. Also known as the North Pacific Garbage Patch, it may hold as much as 1.8 trillion pieces of plastic weighing roughly 80,000 metric tons, spread across an area about three times the size of France, according to the Dutch nonprofit Ocean Cleanup.
The other gyre in the Northern Hemisphere hosts the North Atlantic Garbage Patch, which overlaps with the Sargasso Sea, an oasis for surface-dwelling creatures. "We've known for hundreds of years that the Sargasso Sea is critical to the ecology of the North Atlantic," Helm says. This led her and her colleagues to investigate whether other gyres were rich in life as well.
The scientists enlisted the aid of long-distance swimmer Ben Lecomte, who swam from Japan to Hawaii in 2018 during an attempt to become the first person to swim across the Pacific Ocean—a goal that was thwarted when a typhoon damaged his support vessel. The garbage he encountered on that endeavor made him want to swim across the Great Pacific Garbage Patch. On an 80-day voyage in 2019, he set the Guinness World Record for the longest swim through the gyre, crossing 389 miles.
During the garbage patch swim, the crew aboard Lecomte's 67-foot support vessel, the sailboat I Am Ocean, collected samples of floating life and trash daily, photographing 22 neuston samples. Helm and her colleagues used computer simulations of ocean surface currents to plan the expedition's route and guide it to regions predicted to possess high levels of floating debris.
Before Lecomte and his crew entered the patch, the boat’s net samples were mostly empty. After entering, "we saw just massive amounts of life at the surface," Helm says. "We've seen so many pictures of plastic from the Great Pacific Garbage Patch, but we've never seen any pictures of life there."
Most other garbage patches "likely display similar patterns of neuston abundance, if the driving forces behind the creation of the patches are similar," says Mark Gibbons, a marine biologist at the University of the Western Cape in Bellville, South Africa, who did not participate in this work.
These findings suggest calling these vortexes garbage patches may be misguided. "They were and always will be ecosystems first," Helm says. "I don't like the idea of naming a place after the impact we had on it—I think it obscures the reality of the place, and all the incredible life that lives there."
Sifting through the trash
Relying on this expedition to conduct research had its limitations, Gibbons notes. "Under normal circumstances, we would send a great big research ship out to the North Pacific Garbage Patch and sample using nets, as they did here, but we would then retain the samples, appropriately fixed and preserved for investigation in the laboratory," he says. In this study, the sailing crew was not able to store samples.
In addition, neuston are fragile organisms, limiting what the nets could successfully catch and the researchers could analyze, Gibbons says. And most neuston are effectively transparent, making them difficult to see and capture, swaying the study toward the more conspicuous blue animals.
"One of the biggest questions that remains is exactly how important neuston is to the ecosystem—what role does it play?" Gibbons wonders.
Future expeditions may help fill in the picture, studying how the life responds to changing seasons, for example. "Getting to the center of gyres is expensive science, but it is important science," Gibbons says. "Perhaps we should be putting appropriately equipped buoys out there and monitoring continuously."
Scientists have only just started discovering the extent of these ecosystems, so how the accumulating garbage has affected them is not fully understood. "We have no idea what these ecosystems looked like before plastic," Helm says. "It will take a lot of detective work to figure out what the plastic is doing."
The abundance of life suggests that efforts to entrap the garbage in these gyres could do untold damage. "Dragging massive fishing nets on the surface might have a massive impact on the life there," Helm says. "It might create a much larger problem than the problem we already have with the plastic." Instead, efforts should focus on keeping plastic from entering the ocean in the first place, she notes.
With more exploration and research, scientists may find even more secrets within these masses of artificial junk. "These garbage patches aren't just empty patches where trash is collecting—they're extremely busy with a lot of life," Helm says. "We really need to look at that life more closely and figure out how it connects to the broader ocean."