Written by Quentin Septer

In September 1966, a pair of biologists by the names of Karl W. Kenyon and Eugene Kridler traveled to Hawaii’s Southeast Island. On assignment with the U.S. Bureau of Sport Fisheries and Wildlife, the researchers traversed the shores of the Hawaiian Islands National Wildlife Refuge in search of Laysan albatross. They surveyed the beaches of the island; circumnavigated it. Waves broke on the cloud-colored sand. On a little knoll above the beach, a blanket of grasses and forbs colored a low-lying hillside lively shades of green. And scattered about the sand and vegetation before them, Kenyon and Kridler saw the remains of hundreds of young albatrosses, all of whom died before they could fledge their wings and take flight over the Pacific Ocean. Down along the shoreline, where waves lapped against the beach, the remains of hundreds more young birds “had been broken into fragments by wave action,” the scientists wrote.

Word of seabirds consuming “indigestible material” had been reported since the 1950s. Perhaps that had something to do with the estimated 450 to 500 dead birds on the island. But no one had yet conducted a proper study on the kinds of indigestible matter these birds were eating until Kenyon and Kridler arrived on this small atoll in the Pacific. Examining the stomach contents of the dead Laysan albatross chicks and writing up their findings, Kenyon and Kridler were among the earliest researchers to document ocean plastic pollution in the scientific literature.

As a sample, Keyon and Kridler collected the remains of 100 albatrosses. Inspecting the birds’ digestive systems for clues of their demise, the researchers found fragments of bone, charcoal, wood, pumice, shipping line, squid beaks and plastic debris in the guts of the grounded seabirds. Sorting through the plastic, in particular, Keynon and Kridler discovered bottle caps, plastic tubing, children’s toys, and polystyrene shopping bags. All told, 74 percent of the sampled birds had consumed plastic prior to their deaths.

And prior to their deaths, the birds were newly born Laysan albatross chicks. Until a young albatross can take up flying, the chick is reliant on its parents for food. Laysan albatrosses mate for life, and the parents split their chick-rearing duties equitably. Parenting albatrosses take turns incubating their chicks and leaving the nest to forage far from land, out over the open ocean. When squid, fish, crustaceans and other prey linger too long near the surface of the sea, the birds swoop down and pluck their game from the water. The problem is, plastic afloat in the ocean can look a lot like an easy meal to the eyes of an albatross on the prowl. Mistaking floating plastic and other indigestible material for food, parenting albatrosses bring the junk back to their nests to feed their young. And if enough debris builds up in the chicks’ digestive systems, blockage can occur, organs can rupture, and the fledgling birds can die as a result. 

This, Kenyon and Kridler concluded, was how the birds they studied had died: plastic and other indigestible material was “picked up at sea by the parents and then passed on with regurgitated food to the young.” 

But Kenyon and Kridler’s findings told an even bigger story. As early as 1966, plastic pollution was already so widespread that faraway islands in the middle of the Pacific Ocean had been littered with the stuff. The high-water line of a lagoon on a small, neighboring atoll in the Northwestern Hawaiian Islands—an island chain where an estimated 99 percent of the world’s Laysan albatrosses nest—was “littered abundantly with small plastic items and pumice stones,” Kenyon and Kridler reported in their 1969 paper. “As no channel connects the lagoon with the sea, this refuse could not have been washed to the lagoon from the sea. It must have come from the stomachs of dead birds.”

It’s a grisly image: an entire beach, isolated from the ocean, littered with plastic debris left behind by decomposing seabirds.

Since the time of Kenyon and Kridler, plastic pollution has continued to plague the Laysan albatross. Nearly 70 percent of the entire species’ population nests on Midway Atoll each year—another isle in the Northwestern Hawaiian Islands, about 1,300 miles northwest of Honolulu. There, young albatrosses consume five tons of plastic annually, according to the U.S. Fish and Wildlife Service. Subsequently, about one quarter of Laysan albatross chicks die before fledgling every year. The environmental group Greenpeace estimates an even higher death toll of 40 percent as a direct result of plastic consumption. For comparison, Kenyon and Kridler documented a fledgling mortality rate of 4 to 10 percent on the nearby Southeast Island back in 1966, when ocean plastic pollution was still in its infancy.

Since the time of Kenyon and Kridler’s pioneering research, humanity has produced more than 8 billion metric tons of plastic—a figure nearly quadrupling the carbon-based biomass of all animal life on earth. By 2050, our plastic waste is projected to weigh some 34 billion metric tons. And predictably, threats to Laysan albatross and other ocean seabirds will scale with plastic pollution. “As more plastic is introduced into the ocean, we can expect ingestion rates to increase proportionately,” a Proceedings of the National Academy of Sciences paper states of plastic consumption among seabirds.

Every year sees another 380 million metric tons of plastic produced (about the weight of all human beings currently alive on earth), and every year, an estimated 4.8 to 12.7 million metric tons of this newly produced plastic goes on to enter the ocean. Currently, about 150 million metric tons of plastic is afloat in the oceans of earth. This number is projected to triple by 2040. Riding the currents of the ocean, some of this seafaring plastic makes its way out toward the nesting grounds of the Laysan albatross, where it’s plucked from the Pacific and fed to unknowing young birds.

But the Laysan albatross is hardly the only species to be hard hit by the ills of plastic pollution. Analyzing rates of ocean plastic pollution, as well as previously published data on plastic consumption among ocean seabirds, the PNAS study mentioned above has forecasted what the future has in store for these animals. The data is gloomy. By 2050, the study projects, 99 percent of ocean seabird species will be consuming plastic debris. More than 95 percent of the individual members of these species, too, are predicted to be ingesting plastic by the midpoint of the century. 

It may come as no surprise, then, that ocean seabirds are among the most rapidly declining bird species on the planet. Between 1950 and 2010, an estimated 70 percent of the world’s seabirds died off, as reported in a recent PLoS ONE study. More than one million seabirds die each year as a direct result of plastic pollution alone. And looking forward, things look grim for the Laysan albatross. The species’ population is expected to decline some 30 percent by the end of the century, according to a Conservation Action Plan compiled by researchers from the U.S. Fish and Wildlife Service. And the scope of plastic pollution doesn’t end with seabirds, of course. Upwards of 100,000 marine mammals lose their lives to plastic pollution every year, as reported by the United Nations Educational, Scientific and Cultural Organization (UNESCO). A 2016 report from the United Nations Environmental Programme documented more than 800 marine species threatened by ocean plastic pollution. By 2018, this figure rose to 1,450. These species are large and small; they’re coastal, and they’re dwelling in the deepest depths of the ocean.

Consider a plastic bottle cap afloat on the surface of the sea—precisely the kind of plastic debris that a Laysan albatross might mistake for food. But this chunk of plastic escapes the attention of hungry seabirds. Instead, the plastic is weathered by sunlight and the cresting and troughing of waves. With time, the stuff begins to break down, and smaller and smaller plastic particles known as microplastics begin to take shape. Microplastics—plastic particles less than 5 millimeters in length—look something like little grains of brightly colored sand. Unfortunately for ocean-dwelling wildlife, microplastics tend to look like food, as well. And as microplastics sink, so too does “marine snow”—a steady torrent of sediment, microbes, phytoplankton, the remains of dead and decaying sea mammals and other organic material falling from the surface of the ocean toward the sea floor. This marine snow, as it’s known among oceanographers, provides “a primary source of energy for animals in the deep ocean,” in the words of the National Oceanic and Atmospheric Administration. But mixed up in this food cycle are microplastics. 

A 2019 study published in Royal Society Open Science found amphipods on the floor of the Mariana Trench—the deepest oceanic trench on the planet—feeding on microplastic particles. The organisms—deep sea dwelling, shrimp-like crustaceans—evolved eating marine snow. Now, they eat microplastics, too. And these creatures of the deep blue sea suffer consequences similar to the Laysan albatross—intestinal blockage and potentially, death. Trillions of microplastic particles are afloat in earth’s oceans. Billions more macroplastics (chunks of plastic big enough to be seen with the human eye) sink and float in the sea as well. From amphipods feeding on marine snow in the Mariana Trench, to Laysan albatross foraging plastic in the Pacific, to blue whales washing up on the California coast with bellies full of plastic waste, plastic pollution affects species large and small, far and wide, deep and shallow. 

We humans aren’t spared from the plights of plastic pollution, either. Through the air we breathe, the water we drink, and the food we eat, the average American consumes an estimated 70,000 to 121,000 microplastic particles per year. And once in the human body, microplastic (and even smaller, “nanoplastic”) particles can wreak havoc on our health. Cytotoxicity, oxidative stress, inflammatory immune responses, even DNA damage; all are closely tied to the ingestion of microplastics. Other constituents of plastic, like bisphenol A (BPA)—a plasticizer and an endocrine-disrupting compound found in many plastic water bottles and food wrappers—pose threats to human health as well. The compound has been detected in 93 percent of American study participants, as documented in a 2007 report from the United States Centers for Disease Control and Prevention (CDC). BPA has been linked with “postnatal effects on growth, metabolism, behaviour, fertility, and cancer risk,” a recent study published in The Lancet Diabetes & Endocrinology reads. And BPA, the paper suggests, may have much more potent effects in the human body than previously believed, as the study presents data suggesting that BPA may be biologically active at concentrations nearly 2,000 times lower than is indicated by US Food and Drug Administration (FDA) daily intake guidelines.

While the phrase “plastic pollution” might bring to mind images of plastic bags and bottles afloat in faraway reaches of the Pacific Ocean, or coastlines littered with washed up plastic debris, or decomposing Laysan albatross carcasses leaving bottle caps and children’s toys and polystyrene shopping bags scattered across the sands of a remote lagoon in the Northwestern Hawaiian Islands, the true breadth and depth of plastic pollution is far more insidious and ubiquitous than meets the eye.

And it hits much closer to home, too.