Foraging crabs and hungry fish feed on bacteria from giant tube worms near a deep sea vent in the Pacific Ocean.

The vents are actually springs of super-heated water about 1.5 miles (2.4 kilometers) below the ocean’s surface. They are one of the last frontiers biologists and photographers are working to record.

(Text adapted from and photograph shot on assignment for, but not published in, "Deep Sea Vents: Science at the Extreme," October 2000, National Geographic magazine)