A search to find out why Palau’s coral reefs defied the mass bleaching as predicted by NOAA this year, brought coral reef researchers from Stanford University in California to Palau International Coral Reef Center this week to work with PICRC’s CEO, Dr. Yimnang Golbuu, on finding corals in Palau that are resistant to coral bleaching.


Such corals are most likely to grow and survive as ocean temperatures increase as a result of climate change, according to report released by PICRC. This resistance to bleaching may explain why Palau’s coral reefs have defied the predicted mass bleaching event that was predicted by NOAA this year.

The scientists have started their search in reef areas, most specifically on the patch reefs—areas where corals grow up from the lagoon floor. They chose to focus on these patch reefs are due to the fact that they naturally heat up at low tide in the middle of the day.

“We use automatic temperature recorders,” said Stanford Professor and marine biologist Steve Palumbi. So far, the team has placed these recorders on about twenty patch reefs. After a good low tide series, they retrieve them and transfer the data to a computer file. “We see strong temperature spikes,” Palumbi said, “up to nearly 95°F! Usually, few corals can survive that. But these patch reefs are covered in healthy coral.”

To find out how the corals survive these conditions, the scientists have set up a lab experiment using stress tanks. This is a small Igloo cooler fitted out with computer controlled heaters and chillers. The equipment can apply high temperatures to small coral fragments collected from the patch reefs.

“We were surprised to find that Palau’s patch reef corals were so tough,” said Stanford graduate student Megan Morikawa. The stress tanks act like a human cardiac stress machine where they apply a very standard physiological stress. As such, they can use the results and directly compare them to other test results of corals in other countries.

“We tested corals this way in Samoa, the Cook Islands and the Marshall Island,” Morikawa said. “So far, Palau’s patch reef corals are tougher than them all!”

The researchers have just started mapping Palau’s corals for heat resistance, and hope to work with PICRC scientists for the next few years to complete it. There are two main practical reasons for knowing where heat resistant corals live.

“Heat resistant corals can be fragmented to make coral nurseries that survive bleaching better,” Palumbi said.

Dr. Golbuu added, “Plus, protecting heat resistant corals in marine managed areas helps them survive other problems, and breed the next generation of heat resistant corals.”

The researchers hope the collaboration with PICRC will provide a way for local reef managers to easily find corals that will help assure the future of Palau’s coral reefs and contribute to global knowledge about reef resilience. [/restrict]