Staghorn coral planted by scientists in the Florida Keys. Researchers hope to give the same sort of boost to the world's shrinking population of pillar coral, now that they can raise the creatures in a laboratory. Joe Berg/Way Down Video/Mote hide caption

itoggle caption Joe Berg/Way Down Video/Mote

The city of Gladstone near the Great Barrier Reef is the world's fourth largest coal-export hub. Dredges, like one seen here, have turned the harbor brown as they work to expand the coal port. Richard Harris/NPR hide caption

itoggle caption Richard Harris/NPR

Ken Caldeira of the Carnegie Institution for Science takes a water sample during his experiment out on part of the Great Barrier Reef. The water is slightly pink because his team is using a dye to trace an acid-neutralizing chemical as it flows across the reef. Richard Harris/NPR hide caption

itoggle caption Richard Harris/NPR

Heron Island is located on the southern end of the Great Barrier Reef, about 25 miles off the northeast coast of Australia. Ted Mead/Getty Images hide caption

itoggle caption Ted Mead/Getty Images