Corals and deep-sea flora and fauna

Seen above are some of the wonderful photos of corals and undersea flora and fauna including colorful ornamental fishes, photographed by Dr. P. K. Roy, a professional physician-turned-gifted-photographer. Click on any of the photos above to visit Dr. Roy's collection of works on the photo-sharing site Fluckr.com

Corals are saltwater organisms in the class Anthozoa of phylum Cnidaria, and they live in colonies of many identical individual polyps. This group of corals includes the reef-building corals typically found in oceans in the tropics. They secrete calcium carbonate (CaCo3) to form a hard skeleton, and it is these skeletons that we see most of the time, because, the dead corals form a permanent hard structure and new organisms stick to them further and grow.

Corals are major contributors to coral reefs such as the enormous Great Barrier Reef off the coast of Queensland, Australia, and corals found off the coast of Washington State and the Aleutian Islands in Alaska. A coral head, which looks like a single organism, is actually a colony of myriad genetically identical polyps, each measuring only a few millimeters in diameter. Over several generations the colony secretes a skeleton. Corals also breed sexually as well as asexually.