Among other things, coral reefs have an image problem: their beauty is hidden under the waves — and so is their destruction from a rapidly warming climate.

That’s why in 2014, College of Charleston professor Phil Dustan escorted documentary filmmakers to Carysfort Reef in the Florida Keys.

The filmmakers, Jeff Orlowski, director of Chasing Ice, and Richard Vevers of the Ocean Agency, were just beginning their work on Chasing Coral, a documentary about coral bleaching. Before a dive, Dustan showed them what Carysfort Reef looked like in the 1970s. Then they jumped in the water.

What they saw “blew their minds,” Dustan said. The reef looked like a pile of bones covered in algae. “They realized that they were looking at a dead reef."

This revelation would help propel the producers across the world to chronicle a bleaching event that left biologists in tears and raised fears that entire ecosystems will vanish in a generation. Picked up by Netflix, Chasing Coral premiers on Netflix July 14.

Last fall, The Post and Courier featured Dustan’s work in “Fade to White,” a story that documented the carnage in reefs as close as Charleston and as far as Australia's Great Barrier Reef. Burning coal, oil and other fossil fuels has unlocked massive amounts of carbon dioxide. Carbon dioxide traps heat in the atmosphere, and the ocean absorbs much of this, preventing runaway temperature hikes on land. But even relatively small increases can affect coral reefs. In Chasing Coral, scientists compare it to changes in body temperature — 98.6 degrees is normal for humans, but an increase of three or four degrees over long periods is fatal.

Because of rising water temperatures, some scientists predict that most coral reefs will be gone within 50 years or less.

Early in the documentary, Dustan says Carysfort Reef in 1975 was “was thick” with Elkhorn coral.

One of the producers asks how much Elkhorn coral is left today.

“.01 percent,” Dustan answers.

The documentary then takes viewers across the world during a widespread bleaching event. Using time-lapse photography, underwater cameras capture coral reefs as they lose their psychedelic colors and die. Reviewers have compared the effect to watching birds die in oil spills.  

Bleaching upsets a special symbiotic relationship corals have with algae. Algae live inside corals and provide them with food. But when temperatures increase too much, corals expel the algae. Left behind are the translucent corals and their bone-white skeletons.

If bleaching episodes are short, corals recover. But scientists predict ocean temperatures are at a tipping point.

Near the end of Chasing Coral, a scientist likens the possible loss of Australia’s Great Barrier Reef to the loss of all of the forests from Maine to Florida.

Dustan then tells the filmmakers: “Do we need forests? Do we need trees? Do we need reefs? Or can we sort of just live in the ashes of all of that?”

Tony Bartelme is senior projects reporter for The Post and Courier. He has earned national honors from the Nieman, Scripps, Loeb and National Press foundations and is a three-time finalist for the Pulitzer Prize. Reach him at 843-937-5554 and @tbartelme