The reefs get their color from the algae that live inside them and are the corals’ food. When temperatures get too high, the coral expels the algae, making the reefs appear white or bleached.

Australia’s iconic Great Barrier Reef suffered its biggest ever decline last year after a marine heatwave bleached vast swathes of hard coral, a new report has found.

The reefs get their color from the algae that live inside them and are the corals’ food. When temperatures get too high, the coral expels the algae, making the reefs appear white or bleached.

The reefs get their color from the algae that live inside them and are the corals’ food. When temperatures get too high, the coral expels the algae, making the reefs appear white or bleached.

The reefs get their color from the algae that live inside them and are the corals’ food. When temperatures get too high, the coral expels the algae, making the reefs appear white or bleached.

Two-thirds of the Great Barrier Reef has seen its sharpest annual decline in coral cover since records began 40 years ago, ...

Coral reefs have long been losing their color due to bleaching, but a recent uptick has caused nearly all of the world's reefs to be damaged.

Dying coral Snorkeling the coral reefs off the Florida Keys in the 1960s and 1970s was like swimming through a kaleidoscope, with colorful algae living among roughly 30 coral species covering the ...

“Coral reefs are in a bit of a pickle right now. There’s been hot water, there’s been coral disease, there’s been death of all kinds, and they’ve really drastically changed,” Edmunds said.

The coral reefs off the shores of the Florida Keys should be vibrant and colorful this time of year. But scientists say they're seeing a very different picture.

The temperature of the water also appears to be the primary trigger to determine the coral’s annual window of opportunity to spawn. [Related: To save coral reefs, color the larvae.] ...