With rising sea temperatures, pollution and many other challenges, coral reefs are vanishing at an unprecedented rate around the world.

A recent study offers a glimmer of hope for the survival of coral reefs, particularly off the windward coast of Oahu.

Kaneohe Bay is home to naturally occurring “super corals,” according to researchers at the University of Hawaii at Manoa’s School of Ocean and Earth Science and Technology. These corals have not only survived decades of exposure to raw sewage but are thriving under ocean conditions many predicted would decimate coral reefs worldwide.

“Kaneohe Bay has naturally warmer, more acidic water than many other Hawaiian reefs, similar to conditions that may become common in the future due to climate change and ocean acidification,” said study leader Christopher Jury, a postdoctoral researcher at the Hawaii Institute of Marine Biology. “Many predict that conditions like these will lead to the global collapse of coral reefs over the next few decades and will prevent reefs from recovering in the future.”

Coral reefs in Kaneohe Bay, however, have proven otherwise.

The reefs there were exposed to sewage between the 1930s and 1970s, but appear to have recovered 20 years after sewage was diverted away from the bay, Jury said. This recovery occurred under warmer, more acidic conditions than those on many other reefs.

“We knew that the temperature and chemistry conditions in Kaneohe Bay are very similar to the conditions that people predict will kill off corals globally, yet the reefs in the bay are thriving, making the area incredibly valuable as a possible window into the future,” Jury said in a news release.

The researcher believes Kaneohe Bay could provide a glimpse into the future of coral reefs in a warmer, more acidic ocean and serve as “an incredibly valuable place to start looking for resistant corals.”

For the study, researchers compared three Hawaiian coral species at Kaneohe Bay to those from a nearby control site and found the former were far more resistant to acidification and warming.

Just by looking at them, Jury said, it is difficult to distinguish “super corals” from other corals. When the temperature goes up or the pH measure of acidity goes down, however, the corals show much greater ability to survive and grow than others.

Now Jury and other researchers are focusing on figuring out, in detail, just what it is that makes these super corals more resistant than other individuals of their species. There is a diversity among the physiology of different corals, he said, including how they respond to stressors under varying conditions.

Some corals have higher temperature limits, while others have higher tolerances to acidification than related corals growing on nearby reefs.

But all coral still have their limits, including the super corals from Kaneohe Bay.

“This is not a call for complacency,” he said in the news release. “This is a call for action. We have a chance to save corals if we do something to address climate change.”

Over the next 20 to 30 years, changing ocean conditions and human activities will continue to have negative impacts on coral reefs, according to Jury.

“If we ignore these problems then our generation will be the last one to see healthy, functional coral reefs,” he said. “However, if we take major strides to substantially reduce the rate of climate change, conditions will start to improve. During our lifetime we could begin to see the corals rebound, and our children and grandchildren will witness the recovery of coral reefs because we made the decision that reefs are worth saving.”