Divers relocate coral colonies to a colder area in Florida Keys

Super-heated seawater off the Florida Keys is a danger for the some of the world's third-largest barrier reef and scientists are now removing samples of coral from ocean nurseries to place in cooler land-based tanks.

Sea temperatures off Florida have risen to extraordinary highs this month, presenting a severe threat to the barrier reef. The world's oceans also set a new temperature record this week, raising concerns about knock-on effects on the planet's climate, marine life and coastal communities.

Oceans have absorbed 90 percent of the excess heat produced by human activity since the dawn of the industrial age, according to scientists. This excess heat continues to accumulate as greenhouse gases -- mainly from burning oil, gas and coal -- build up in the Earth's atmosphere. Globally, the average ocean temperature has been topping seasonal heat records on a regular basis since April.