In the first ecosystem-wide study of changing sea depths at five large coral reef tracts in Florida, the Caribbean and Hawai’i, researchers found the sea floor is eroding in all five places, and the reefs cannot keep pace with sea level rise. As a result, coastal communities protected by the reefs are facing increased risks from storms, waves and erosion. The study, by the US Geological Survey (USGS), is published today in Biogeosciences, a journal of the European Geosciences Union.