Days after hurricanes Irma and Maria tore through Puerto Rico in 2017, Ernesto Diaz formed a team to survey what the Category 5 storms had done to his home. Touring coastal areas, Diaz, then an assistant secretary with the commonwealth’s Department of Natural & Environmental Resources, saw rooftops poking out from floodwaters, forests stripped bare, and windows and doors floating by. As a marine scientist who knew the shoreline ecosystems intimately, he also noticed something that intrigued him...