Diving for Disaster: When the Coral is Gone

Documentary Highlights the Little-Known Impact of Coral Reef Destruction

Chasing Coral
Photo credit: Exposure Labs
Reading Time: 4 minutes

Our survival — and, for that matter, the continued existence of all life on earth — may be bound up with the well-being of coral reefs.

These sea creatures, with their astounding shapes and psychedelic colors, look like they’re from another planet. Contrary to popular belief, they are not plants, but marine animals.

And they are not doing well, as powerfully demonstrated in the new documentary Chasing Coral, which I saw at this year’s Sundance Film Festival.

Human activity — from ocean-front development and overfishing to myriad sources of pollution — are steadily killing these fragile, crucial ecosystems, affecting some 60% of the world’s reefs.

Add to this rising ocean temperatures — attributed by scientists to global warming — and you have a situation where three-fourths of the world’s coral is on the brink of annihilation. Half of the world’s largest reef — Australia’s Great Barrier Reef — was lost during the last 30 years.

And the destruction is accelerating: nearly a quarter of the remaining reef was lost in 2016 alone. By the time you read this, the figures will probably be worse.


Chasing Coral was directed and shot by Jeff Orlowski, whose 2012 Chasing Ice essentially proved the reality of climate change to anyone with an open mind. Now he’s done the same for coral death.

Orlowski makes clear that reefs aren’t just the cool phenomenon so many of us think they are. They provide homes and food for millions of fish and other animals. So by killing coral, we’re also devastating the livelihoods of fishing communities worldwide — and messing with our own food chain.

Coral reefs have been called the “rainforests of the sea.” Like trees, they provide food and shelter — a safe haven for spawning, a refuge for juvenile fish and other animals until they are ready for the open sea.

They are also a natural barrier, protecting coastal areas, minimizing wave impacts from hurricanes. Their underwater peaks and valleys slow waves down before they make landfall, minimizing wave impacts from hurricanes, and reducing coastal erosion.

The economic value of coral reefs — for the fishing industry, the pharmaceutical industry, coastline protection, and tourism — amounts to billions of dollars a year, supporting millions of jobs around the world.

Medicine Chests of the Sea


Coral reefs have been called the “medicine chests of the sea.” From the plants and animals intertwined in the coral reef ecosystem, scientists are developing — or have already developed — drugs to treat cancer, leukemia, lymphoma, heart disease, AIDS, diabetes, Alzheimer’s disease, viruses, bacterial infections, as well as medicines that reduce inflammation, and relax muscles. And because corals are stationary, they have evolved chemical defenses to protect themselves from predators. Scientists are also researching the medicinal potential of these substances.

In addition to life-saving drugs, coral reefs are also potential sources of nutritional supplements, cosmetics, pesticides, and more.

Coral and Algae


The study of coral has revealed a fascinating ecology of interspecies cooperation at work. Coral reefs are colonies of individual animals that feed on plankton at night with their tentacles. But what is most important about them is what controls their existence — and, indirectly, your existence: the symbiotic relationship between the coral and the algae that live within their tissues, and give the colonies their color.

The coral provides the algae with its waste products and CO2  which the algae need for photosynthesis. In return, the algae provide the coral with oxygen and the products of photosynthesis — which the coral needs to make its limestone skeleton.

When stressed, corals respond by — expelling their algae! Loss of algae is known as “bleaching” since the coral gets its color from algae. Bleaching leaves coral weakened, prone to disease and, eventually, without algae, this living organism is turned into stone. (To learn more about this complicated process, please go here, here, and here.)

Rising ocean temperatures are a major, global source of stress to coral. Ocean acidification — climate change’s “evil twin” — is another great threat to coral. It corrodes pre-existing coral skeletons and interferes with the growth of new ones.

Local threats include unsustainable fishing and destructive fishing practices (use of cyanide or explosives), pollution, sedimentation (muddying waters from dredging, changes in salinity, and even plastic bags which can smother coral. (Please see our earlier story on plastic.)

Watch it Happen


Over three years in the making. Chasing Coral takes us on what Orlowski calls a “crazy epic trip” by ranging across the globe, from nearby tropics to far away exotic places, and using time lapse photography to capture the death scene, as we watch one coral reef after another bleaching … then dying.

One moment we see a lush, vibrant, underwater forest, teeming with life, or a place where the coral lights up the ocean floor with an array of fluorescent colors, until there’s a bleaching event. Then we see them turn to stone.

Like a lot of doomsday films, Chasing Coral employs the somewhat uplifting ending, a seemingly essential marketing ploy to prevent total despond and paralysis. Yet his work is effective enough to give us the sinking feeling that the game is already over. The situation in Washington only contributes to that sense. But maybe…maybe not. At best, time is extremely short.

NOTE: Chasing Ice screenings can be found by visiting https://www.facebook.com/chasingcoral/. The documentary was snapped up by Netflix at the Sundance Festival. On Netflix, it can be added to “your list” and Netflix will let you know when it’s available for viewing. There’s also going to be a Virtual Reality version of Chasing Coral where the impact of the bleaching is even more tangible. I got a preview and it’s an intense and personal experience. More info on the film here.

Related front page panorama photo credit: Adapted by WhoWhatWhy from coral (Neo Wu / Flickr – CC BY-NC-SA 2.0).

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9 responses to “Diving for Disaster: When the Coral is Gone”

  1. Geoff Botting says:

    Sorry Wendell, here is some truth to your Professor Hughes cited literature;

    “The chairman of the Great Barrier Reef Marine Park Authority, Russell Reichelt says that activist groups are distorting surveys, maps and data to exaggerate the coral bleaching on the reef. The bleaching affects 22% of the reef and is mostly localized to the far northern section, which has good prospects of recovery.

    Dr Reichelt said the authority had withdrawn from a joint ­announcement on coral bleaching with Professor Terry Hughes this week “because we didn’t think it told the whole story”. The scientific paper lead-authored by Hughes said mass bleaching had killed 35 per cent of corals on the northern and central Great Barrier Reef.

    Dr Reichelt said maps accompanying the research had been misleading, exaggerating the ­impact. “I don’t know whether it was a deliberate sleight of hand or lack of geographic knowledge but it certainly suits the purpose of the people who sent it out,” he said. “We don’t want to be seen as saying there is no ­problem out there but we do want people to understand there is a lot of the reef that is unscathed.” Dr Reichelt said there had been widespread misinterpretation of how much of the reef had died.

    “We’ve seen headlines stating that 93 per cent of the reef is prac­tic­ally dead,” he said.

    “We’ve also seen reports that 35 per cent, or even 50 per cent, of the entire reef is now gone.”

    No matter, I am sure the Chairman of the GBMPA is a climate change denier.

    Don’t always believe published papers or cite them without fact checking them first.

    Regards, Geoff

  2. Geoff Botting says:

    Still waiting………

  3. Geoff Botting says:

    Still waiting.

  4. Geoff Botting says:

    The silence is deafening…any response would be polite one would think!

    • Wendell F. Perks Jr. says:

      Geoff Botting,
      It appears, according to the study published in the 16 March 2017 publication of
      “Nature,” that the recovering of the Great Barrier Reef is more under
      threat now than in previous periods.

  5. Geoff Botting says:

    “Half of the world’s largest reef — Australia’s Great Barrier Reef — was lost during the last 30 years.”

    Can you provide a valid, peer reviewed scientific reference to substantiate this claim ?

    Australian coral reefs regularly experience ‘coral bleaching’, recent events have occurred but the reefs generally recover. Most are caused by El Niño weather events and have been recorded as far back as the late 1800’s, I should know, I worked, up until recently, in the marine science field, including studies on the impacts of anthropogenic and natural impacts to corals, sea grasses, water quality and othe marine flora and fauna.

    Broad brush statements do very little to one’s credibility and make it difficult for the less knowledgeable and informed to reach objective conclusions if wild claims are made in what is a very important realm of science.

    I look forward to reading the literature which supports your claims.

    • Wendell F. Perks Jr. says:

      Geoff Botting,
      According to: “An Australian Government report into the state of the Great Barrier Reef found that its condition in 2014 was “poor and expected to further deteriorate in the future”. In the past 40 years, the Reef has lost more than half of its coral cover and there is growing concern about the future impacts of ocean acidification and climate change.”

      This is from the ARC Centre of Excellence, Coral Reef Studies, 2015 Annual Report, in which it also references: Hughes, TP, Day, JC and Brodie, J (2015). Securing the future of the Great Barrier Reef. Nature Climate Change 5(6): 508-511.

      Unless Russ Baker has more updated information on the reef’s condition, in stating only the “…last 30 years,” it appears the time frame he mentioned in this article may be less than reported by Australia; although I have not finished researching on-line to find more recent studies or peer-reviewed papers.

    • PJB says:

      Caution is advised when inferring catastrophe from cyclical changes. The geological record is full of various rises and falls of coral, sea-ice, glaciers, global temps etc. Peer-reviewed studies are often agendized (eg. Marcott et al, in Science) partial and speculative or just plain WRONG. Sadly, Academia is just as prone to influence by funding as any other field or endeavor.
      Corals have survived for millions of years through much worse than this (Deccan flats etc.) much warmer ocean temperatures (they fill the niche temperature that they adapt to, wherever that is on the globe) and follow sea levels, just like the atolls that they form.

    • Geoff Botting says:

      Too true PJB, nice to read common sense sage words occasionally, thanks. It would have been nice to hear from Russ direct, but I suspect he is too busy to respond to all posts.
      Cheers Geoff (Perth, Western Australia)