Oysters can be shocked into repopulating and cleaning up America's waterways, the Christian Science Monitor reports. A project in New York's East River is using metal reefs, powered by solar panels, to build up limestone and help oysters grow. The upside is that they filter water—up to 50 gallons a day per oyster.
The New York project is part of a bigger movement to revive ecosystems along the East Coast. They begin with attempts to restore keystone species like oysters, which once spread widely and could clean a bay in days. “The degree that the oyster, as a filter feeder, was able to keep the bay clear of nutrients is a very important function,” one expert says. "And it's gone."