In many ways, plastic is the perfect material—we can make it strong and rigid enough to build spaceships and replace bones, or thin and flexible enough to make shopping bags that weigh as much as a nickel but carry up to eight kilograms. And unlike other materials, plastic doesn't rust or rot. It can last for centuries, even when we only need it to last a few seconds. We make tons of plastic precisely because it's cheap, durable and yet expendable. But the features of plastic that make it so useful to us have also transformed life in the oceans, where as much as 10 percent of our discarded plastic, millions of tons per year, ends up.
Big pieces of plastic are definitely bad news for marine animals like whales, albatross, and sea turtles, which risk getting tangled in the debris or ingesting large pieces of it. Yet, despite the publicity about huge garbage patches in the sea, most of the ocean's plastic isn't big. Our castaway shopping bags and soda bottles get weakened by sunlight and torn apart in the wind and the waves into little bits of plastic confetti. On the microscale, though, it's still super durable. The microorganisms that decompose ripped-up bits of wood and seaweed down into simpler organic compounds can't easily digest plastic. So while the plastic confetti gets broken into smaller pieces, it doesn't go away. It just spreads out over time, which is why we've found microplastics pretty much everywhere in the oceans, from the Arctic to the Antarctic, and from the seafloor to the surface.
Unlike the easy-to-observe impacts of large plastic trash, the effects of microplastics are as subtle and difficult to trace as the fragments themselves. The durable fragments can serve as new real estate on which small ocean creatures grow and multiply, or choke slightly larger ocean creatures that think the plastics are food, or attract and collect toxic chemicals which become introduced into the food chain if the particles are eaten, and probably a million other problems we haven't noticed yet, because we've only recently started paying attention to all these microplastics in the oceans. But it's undeniable how much plastic trash we've introduced into marine ecosystems, and the wonderful durability of plastic guarantees it'll be an issue for years to come.
It's possible we can decrease further impacts by switching to biodegradable plastics, dumping less plastic in the oceans, or cleaning up the patches of sea most strewn with plastic. But until we do, the question is, Will the oceans be plastic enough to deal with our favorite material?