Hard coral gains some of its food from filtering the water, but most of its nourishment comes from a synergistic relationship with algae that live within its tissue. The algae need sunlight and water to survive so hard coral is usually found in shallower water. Being shallow, as well as somewhat fragile, increases the probability of tsunami physical damage. Even a slight layer of silt can impede the algae's ability to survive. The color of hard coral is from the algae. When the algae die, the coral turns white and is called "bleached."

12/21/04 8:29:30 AM
Country: Thailand
Area/City: Similan Islands
Speed: 1/125 sec
Aperture: f1.8
ISO: 64
Focal Length: 7.1 mm
Flash: