It's sex on the reef.

Every year near the middle of August, corals ringing the Florida Keys and western Caribbean go into a frenzy of reproduction, sending the genesis of the next generation to mix and hopefully mingle in the currents. Clouds of the colored bunches of eggs and sperm float to the surface where they open, and the process of eggs and sperm meeting begins.

It's an amazing sight. It looks like a snowstorm underwater,'' said Carl Beaver, a marine scientist with the Florida Marine Research Institute in St. Petersburg. Different species spawn on different nights. One night it might be brain coral. Another, it could be a species of star coral.

Visually spectacular, the coral spawning is also a vital biological event evolved over thousands of years, an orchestration of timing and proper conditions. Wired somewhere in the genetic circuit board of the coral is something that triggers the spawning. It has no brain. No central nervous system. No communication we can understand, yet all the colonies know when to spawn,'' Beaver said.

Within the entire Keys, all the coral of one species will all spawn at the same time. Although scientists can't predict the exact day any species of coral will spawn, it usually happens about eight days after August's full moon, almost always at night and just after the water has reached its warmest temperature of the year.

This year, the clock for the main event starts ticking Aug. 12, when the moon waxes full.