The poop of seabirds, such as this red-footed booby chick, contains nitrogen that leaches into coral ecosystems. That nitrogen helps the reefs stay robust.

Sixteen out of these 17 deep-sea octopuses are brooding young. However, young and old, all are fated to die.

Staghorn coral may be able to last 100­ to 250 years thanks to its ability to adapt to warming waters, a new study shows. Here, a healthy staghorn grows off Magnetic Island in the central part of Australia’s Great Barrier Reef.

This map shows where fish were harvested from the world’s oceans in 2016. To make the map, researchers tracked the activity of more than 70,000 fishing vessels. Colored dots represent the average hours of fishing activity within an area spanning 10,000 square kilometers (3,860 square miles).