What is coral bleaching? Crisis posing threat to existence of Australia's famed Great Barrier Reef

For 33 years marine biologist Anne Hoggett has lived and worked on Lizard Island, a small slice of tropical paradise off Australia's northeast tip. The only relief from the wind and teeming showers is in the powder blue waters, where sea turtles and tiger sharks rove along the Great Barrier Reef. "We don't know yet if they've already sustained too much damage to recover or not," said Hoggett. The world is currently experiencing its second major coral bleaching event in 10 years, the US National Oceanic and Atmospheric Administration (NOAA) announced Monday.