Coral reefs are both vital and vulnerable to change, and the combination of rising ocean surface temperatures and increased acidification is devastating corals across the globe in one of the worst bleaching and die-off events ever recorded.

"Right now, coral reefs around the world are either bleach, dead from bleaching, or trying to recover from bleaching," says C. Mark Eakin, who heads the NOAA's Coral Reef Watch. "2010 has been a major, major year of bleaching in all of the oceans around the world."

Local bleaching can occur with changes in ocean salinity, nutrient runoff, and other pollutants, but scientists say the large-scale bleaching currently underway is indicative of coral's sensitivity to record ocean warming.

Coral reefs are a foundation for a healthy ocean ecosystem, serving as home for a wide variety of plants and animals.

Coral communities play a vital role across the entire food chain, from the tiniest creature right up to humans.

The National Oceanic and Atmospheric Administration (NOAA) estimates that healthy coral reefs generate up to $375 billion annually in food, jobs, and tourism.