A new study shows that the world's oyster reefs are a precious resource that's vastly underestimated and underutilized. The authors set out to calculate the reefs' potential gross ecosystem product (GEP), the ecological counterpart of the gross economic product, and arrived at trillions of dollars in ecosystem goods and services delivered each year to different aspects of planetary health, including human well-being. But for their full potential to be realized, oyster reefs around the world will need to be restored and protected.