It’s about four o’clock in the afternoon on a clear day last November onboard the S/Y Christianshavn, a 54-foot Danish steel sailboat, which is bound to Honolulu from Los Angeles, across the most famous plastic-clogged place on Earth: the Great Pacific Garbage Patch.

As most days on the 23-day journey, I spend my free time in the cockpit on the lookout for trash. Every once in awhile I see disturbingly familiar plastic items float by—a pink dustpan, a punctured green condiment bottle, a barnacle-covered Tupperware lid, a white Styrofoam packing wedge. Then I notice a cloudy white blob floating on the water’s surface—hundreds of white plastic pieces, some tiny confettilike bits and some robust, rugged chunks that look like peeled paint chips.

I stick my head over the ship’s railing for a closer look. Near the floating mass of white plastic there is something else in the water—something small, finned. Something alive. I watch as a quarter-size blue-green larval fish swims to the surface, opens its mouth and swallows a bit of plastic the size of a pencil eraser. Within moments the fish and plastic have floated away. “You just got a firsthand look at how plastic gets into the food chain,” Kristian Syberg tells me a few minutes later. Syberg is an associate professor of environmental risk at Roskilde University in Denmark and one of two resident scientists onboard the vessel, which has set out to measure the smallest, most toxic pieces of plastic in the ocean, called “microplastic.” Prior to this voyage scientists have never before searched for plastic deep in the Pacific Ocean water column. “It’s the smallest fish that eat the most plastic and become toxic. Then the middle-sized fish eat those smallest fish and become a little more toxic. Then the larger fish eat those middle-sized fish and become even more toxic. And then we eat the largest fish…,” he notes.

Suddenly, I think twice about consuming the mahi-mahi we’ve caught for dinner that night.

A Growing Problem

Plastic can be detected in the bodies of more than 50 percent of the world’s sea turtles. Scientists estimate 90 percent of all seabirds have ingested plastic at some time in their lives. Fish, too, contain plastic and appear to consume it in large quantities when it is available.

Although there is a huge amount of plastic trash that has accumulated on land, much of the world’s plastic resides in the oceans, where it is deposited after being whisked there by the wind from land, being dumped at sea or on the shore or being carried there in runoff from rivers and streams. Scientists predict that by 2050 there will be more plastic in the oceans than fish.

Current estimates put the oceans’ total plastic load at 165 million tons. But that is just based on plastic samples collected from surface trawling. More microplastic found at greater depths in the oceans means scientists might be greatly underestimating the total amount of plastic in the ocean—and its total effect.

Syberg’s expedition entails collecting water samples and trawling this famous stretch of ocean for evidence of microplastic. His group's previous research in the Atlantic Ocean revealed that microplastic exists at a greater depth than previously believed. What is more, a 2016 study found that seafloor animals like lobsters, sea cucumbers and hermit crabs, which can live at depths of up to 6,000 feet, have consumed the stuff.

Pervasive Plastics

Plastic is so pervasive in the natural environment that if you took a look inside the body of any animal—on land or sea—you would likely find at least a trace of plastic, Syberg says. That includes inside us humans. “Unfortunately,” he adds, “to date no systematic studies can confirm plastic is present in people on a wide scale. Not enough money or attention has been allotted to address this issue.”

Although the garbage patch is typically portrayed as “a floating island of plastic trash the size of Texas,” in actuality it only contains the occasional large piece of trash or fishing gear, and is mostly a large soup of microscopic plastic bits, many of which are too small to see with the naked eye. That is because plastic breaks up over time, but never fully breaks down.

When plastic is exposed to UV radiation from the sun and mechanical movement of waves, it breaks into little pieces. As I saw firsthand, fish tend to eat small pieces of plastic, mistaking it for plankton, their preferred food source. Research reveals consuming plastics can increase fish mortality by causing behavioral and physical abnormalities such as slowed reaction time and reduced size. Scientists hypothesize these problems are caused by the man-made chemicals plastic absorbs from seawater. The worry now is these tiny toxic pieces of plastic may affect more than just fish—possibly causing cancer in humans, altering our hormones and maybe even killing us. “In a little more than 60 years, we know we’ve littered more than 150 million tons of plastic into the oceans,” says Henrik Beha Pedersen, founder and president of the Danish nonprofit Plastic Change. “Where does it all end up? Is it in the fish? Is it in the birds? Is it on the beaches? Is it on the deep-sea floor? Where has all the plastic gone? Is it in us, us humans?”

Research and Change

Over the course of the expedition, Syberg and Malene Møhl, an advisor on chemicals to The Danish Ecological Council and Plastic Change volunteer, trawl for plastic, and additionally gather water at 200 meters down in the water column, flesh samples from fish and bits of seaweed. Back in Denmark it will be Syberg’s responsibility to process the samples, estimating how much microplastic is in the Pacific. He will also test for chemicals in the plastic, fish and seaweed, which will help him determine to what degree plastic acts as a “vector,” soaking up and delivering toxic chemicals in the bodies of living things.

It is research that is most helpful in combating our plastic problem, according to National Oceanic and Atmospheric Administration agent Mark Manuel, regional coordinator of NOAA’s Pacific Islands Marine Debris Program, whom I meet up with in Honolulu a few weeks after Christianshavn's journey ended in Kewalo Basin Harbor. He says with government environmental agencies—including his own—strapped for cash and staff, it is largely up to nonprofits like Plastic Change to gather data that, when analyzed and published, can push plastic-curbing policies like plastic bag, microbead and Styrofoam bans, which he says appear effective in curbing plastic use and reducing pollution. For example, San Jose, Calif., officials found a 2012 ban on plastic bags in their city helped reduce plastic litter in streets by 59 percent, storm drains by 89 percent and creeks by 60 percent as well as increased consumer use of reusable shopping bags.

In the future Syberg hopes he and other researchers will be able to get the funding they need to pursue studies on the effects plastic has on human health—the last big question remaining after the total amount of plastic in the world’s oceans is properly quantified. As of now a substantial portion of the research effort comes from the nonprofit sphere—organizations currently collaborating with scientists to study plastic include 5 Gyres Institute, Mission Blue and Greenpeace.

NOAA currently provides grants to nonprofits for plastic education, cleanup, pollution prevention and research projects—such as trash surveys—in the Pacific and in coastal regions across the U.S. Manuel says he has found one of the biggest challenges to getting more data on marine debris and microplastic is garnering enough volunteer help.

“Changing behaviors can be hard, but we’ve seen how nonprofits’ research can help get policies passed,” says Manuel, a Big Island native and father of two young sons. “It can be hard to incentivize spending hours counting and cleaning up trash on a beach, for free. Yet the more people that get involved, that help to get the science done…the closer we get to cleaning up this mess.”