Beneath a cloak of darkness, illuminated only by glow sticks and red-filtered flashlights, researchers waited underwater off Key Largo hoping to witness one of the rarest events of sex in the sea.

The Great Barrier Reef has "given birth" in its annual coral spawn, creating a cacophony of color on the Australian landmark. Scientists working beneath the waves say they witnessed the event, in ...

It's a delicate spectacle called the coral spawn - a once-a-year phenomenon when Florida's reef-building coral colonies simultaneously release tiny bundles of eggs and sperm. They float to the surface ...