High up in the Andes mountains, 12,000 feet above sea level, lies one of the world’s most unique ecosystems. Known as Páramo, the landscape is responsible for 70% of Colombia’s fresh water; in part, thanks to moss species that trap moisture from the fog, rain, and melting glaciers; store it in the soil; then release it gradually to the lowlands. When the water passes through the moss, it’s so clean it’s considered safe to drink for about 40 million people across Columbia, Peru, Bolivia, and Ecuador. But the moss can filter a lot more than dirt and pollutants: It can also filter microplastics.