beach, or a turtle looping in circles with the plastic collar of a six-pack wrapped around its neck. In the past, those powerful images have generated interest and resources for fighting marine pollution, but now a new, much tinier threat is emerging.

Microplastics — meaning any plastic object smaller than five millimeters — constitute the vast majority of plastic particles polluting marine habitats.

Of those microplastics, a large share are microfibers: tiny strands of plastic that are woven into fabric used to make clothing. These fabrics, known by names like polyester and nylon, are cheap to produce, comfortable to wear, and since arriving on the market in the late 1940s, companies have been using more and more of them. Every time we do laundry, a small amount of microfibers are separated from clothes made from these materials. Since those pieces of plastic are extremely small, they’re able to make their way through water treatment centers and into marine resources. Once they reach marine habitats, the ocean’s tiniest creatures consume them, and microfibers work their way up the food chain. Eventually, they reach us.

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