Coral Reef

Coral Reef, Australia, 2001

The serene blues and greens of a coral reef blend in with waters off Australia. Corals live in tropical waters throughout the world, generally close to the surface where the sun's rays can reach the algae. While corals get most of their nutrients from the byproducts of the algae's photosynthesis, they also have barbed, venomous tentacles they can stick out, usually at night, to grab zooplankton and even small fish.