What Is Marine Debris?
In the simplest terms, marine debris is trash that ends up in the ocean. But the nature of that refuse has changed over time. It used to be that most of the items that found their way into our oceans were biodegradable, like wood, paper or cloth. Now they’re made of metals and plastics, materials that are not easily broken down.
The amount of garbage is also increasing at an alarming rate. “We’ve looked at more than 100 beaches across the California coast and every single one of them has microplastics,” says CSU Channel Islands professor Dr. Sean Anderson. “Then our CI faculty and student teams looked at sand crabs that live up and down the coast and found every single population has ingested microplastics.”
Researchers have found the presence of microplastics in the
50 marine mammals they tested, including dolphins, seals and whales. Anderson and his colleagues have even found microplastics in air and rain, from Alaska to Florida.
So where is it all coming from? The classic sources of pollution still apply: a plastic cup blows into the ocean, dries out in the sun and is then smashed into tiny pieces by waves. But newer and more insidious types of garbage are plastic microfibers—tiny plastic "hairs" shed from our clothing—and microspheres (also called microbeads), solid particles that add grit to toothpaste and cosmetics.
As these flow down drains from sinks and washing machines and into our water treatment plants, they’re too small to be filtered out and end up in the sea (as well as in rivers and lakes). The U.S. releases
eight billion plastic microbeads into aquatic ecosystems
a day and an estimated
1.4 trillion microfibers are already on the floors of the world’s oceans.
Adding to the accumulation of plastic in the ocean: lost fishing gear, which accounts for
700,000 tons a year. Even this may be related to climate change, Anderson says. “When fishermen deploy nets or lobster pots the way their dads taught them, they may be leaving them in the water too long or in areas vulnerable to new storm patterns, leading to increased loss of that equipment. When we have less predictable ocean conditions, fishermen are more likely to lose their gear.”