Between 2000 and 2012, the giant barrel sponge, Xestospongia muta — which can grow to over a meter tall and wide — covered increasing territory on two reefs off Florida’s Key Largo. The number of sponges per square meter increased on both reefs, on one by an average of 122 percent, researchers report in an upcoming Journal of Experimental Marine Biology and Ecology. More baby sponges attached to the reefs while existing sponges survived and grew, says study coauthor Joseph Pawlik, a marine biologist at the University of North Carolina Wilmington.