ARC center, coral bleaching, coral reef bleaching, Great Barrier Reef, marine conservation, global warming, climate change,Australia’s Great Barrier Reef is one of our most spectacular natural wonders and the world’s largest structure created by living organisms. The reef stretches for 2300 kilometers, covers approximately 344,400 square kilometers and is composed of over 2,900 reefs and 900 islands. The building of the current reef is thought to have begun over 20,000 years ago. What required 20,000 years to create may have been largely destroyed over the last eighteen months. So, is the Great Barrier Reef Dead? Let’s look at the latest reports. (photo – Terry Hughes/ARC/Nature)


Second Year of Severe Coral Bleaching On Great Barrier Reef

The Great Barrier Reef is now in its second, consecutive year of severe coral bleaching, a result of record ocean temperatures. We have been closely following this crisis as it unfolds and it’s beginning to feel like sitting bedside with an elderly parent as their life support systems begin to shut down.  2016 saw the worse coral bleaching in the history of the Great Barrier Reef and 2017 appears to be developing into another period of severe bleaching. Consecutive years are especially destructive because there is no opportunity for weakened corals to recover. (photo – Terry Hughes – ARC)


What is Coral Bleaching?

captive, coral reef algae, coral reef, corals, marine conservation, Great Barrier Reef Corals live in a symbiotic relationship with photosynthetic algae. The coral provides a protected environment for the algae and certain compounds. In return the algae supplies nutrients that enable the coral to produce calcium carbonate, the building blocks of coral reefs. Algae also gives the coral its distinctive and beautiful colors. (photo –

But when the coral is under stress, most often during warm summers when the sea temperatures rise, the coral polyps will expel the algae leaving the coral starkly white, a state that is described as coral bleaching. If the stress is temporary then the coral might be able to recover, however if stress events repeat there is little opportunity for the algae to recolonize the coral and the corals essentially starve.

Surveys conducted late last year after the 2016 event showed extensive areas of the northern third of the reef (60% to over 80%) that had died and were unlikely to recover. Back to back years of extreme temperatures and coral bleaching were unheard of in Australia, until 2017.

“Mass bleaching events 12 months apart offer zero prospects of recovery for reefs that were damaged in 2016,” Kerry ARC marine biologist


Recent Surveys Just Released

ARC Center, Great barrier Ref, 2016 2017 coral bleaching, coral bleaching, coral reef bleaching, climate change, ocean acidification, This last week new aerial surveys show the entire extent of the coral bleaching over the last two years. ARC the Australian research Council announced that 900 miles of reef have bleached in 2017, with the most severe bleaching occurring in the middle third of the reef.

“I don’t think the Great Barrier Reef will ever again be as great as it used to be — at least not in our lifetimes,” said C. Mark Eakin, a reef expert with NOAA

The Huffington Post estimates that 93% of the Great Barrier Reef has been impacted by coral bleaching. Also see the New York Times and the Guardian

We’ve never seen anything like this scale of bleaching before” said Terry Hughes, of the National Coral Bleaching Taskforce, ement. “In the northern Great Barrier Reef, it’s like 10 cyclones have come ashore all at once.”


Update: Hurricane Debbie has delivered some cooler waters (up to 3C) to the great barrier reef that hopefully might mitigate the 2017 coral bleaching. However Terry Hughes cautions that “Cyclone Debbie has come a month too late and in the wrong place to prevent mass bleaching,”  Read more.


Worldwide Coral Reefs are Under Severe Stress

These bleaching events are not isolated to the Great Barrier Reef. As we reported last week in: Worldwide Coral bleaching in 2016 and 2017?  Reefs further north in the South China Sea and Japan were also severely impacted by the events of 2016 and may face further stress this year. Reefs in the Caribbean are estimated to have lost approximately 80%. And even reefs that have had an opportunity to recover as in the Seychelles do not recover completely. Of the reefs in the Seychelles bleached in 1997-1998, 12 have recovered and nine are completely dead.


Conservation Efforts to Combat Coral Bleaching

Mote Lab, coral nursery, coral reef restoration, coral bleaching, coral reef bleaching, marine conservationRecently we posted that there were some amazing efforts to understand the dynamics of coral bleaching and combat its destructive effects. See: Saving Coral Reefs; With Innovation.

We Must Act Now!

These heroic efforts include creating coral nurseries and replanting coral on destroyed reefs. Finding coral types that will better tolerate a warming ocean environment and even using 3D printing to create artificial reefs. However, faced with the immensity of what is being lost as measured in thousands of square kilometers of reefs, each of these ocean heroes will state that the most important way to save the world’s coral reefs is to combat global warming and climate change. And we must act now! (photo – Mote Marine Lab)


What Is At Stake

reuters, fishing, coral reefs, coral bleaching, marine conservation, coral bleaching.,Our coral reefs are the incubators of the oceans, giving shelter to reef fish that form the lowest rungs of the ocean food chain. Approximately 1 billion of the world’s population depends directly on the ocean for food sustainability and their livelihood. If coral reefs fail, this food source will disappear, displacing millions of people, and placing extraordinary challenges on local and international governments. (photo – Reuters)

See our Blue Ocean post on how climate change is effecting the traditional migrations of fish, see: Marine Migrations Magnified by Ocean Warming.


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See These Related Posts on Coral Reefs

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Protect Our Coral Reefs from Ocean Acidification
Why Coral Reefs are One of the Most Valuable Ocean Assets – Dr. Douglas Fenner
Research Shows Efforts to Save Coral Reefs Not a Lost Cause