Coral bleaching has been detected again in several sites in Palau according to studies conducted by the Palau International Coral Reef Center (PICRC). The coral bleaching is said to be likely due to changing weather patterns.

PICRC CEO Dr. Yimnang Golbuu said that so far the bleaching does not seem as widespread as it was in 2010  or earlier in 1989.

PICRC researchers say that so far the bleaching is not too extensive, although minor bleaching has been found in many of the observation sites. Some sites, such as Risong Bay, have suffered a greater amount of bleaching, probably due to warmer water temperatures.

Dr. Yimnang Golbuu said that the center plans to conduct a more elaborate study to establish the full extent of the problem.

“We are planning to do a spatial assessment of this bleaching, similar to what we did in 2010,” said Dr. Golbuu. “That would tell us if our reef’s response to warmer waters is changing or similar to what we saw in 2010.”

A model used to predict coral-bleaching months in advance, co-authored by PICRC earlier this year, allegedly predicted this bleaching would begin when it did.

Dr. Peter Houk from the University of Guam Marine Laboratory, the primary author of the model used to predict coral-bleaching in the Micronesian region, also reported that corals are bleaching in Yap.

The model, which uses coral-reef monitoring datasets from around the Micronesian region, determines when coral reefs will begin to start bleaching, taking into account weather patterns such as El Nino- Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). Both ENSO and PDO involve a phase of warmer ocean surfaces and a phase of cooler ocean surfaces in the Pacific, although while ENSO involves cycles spanning six to eight months, PDO involves cycles spanning up to thirty years.

The model predicts that periods of negative ENSO and PDO will coincide with coral bleaching in Palau. La Nina, the shift from warmer to cooler ocean temperatures which is currently taking place along the equator, is one of those periods which allegedly triggers bleaching.

Studies used to shape the model have shown that it took Palau’s reefs between nine and twelve years to fully recover from a mass bleaching event in 1998 which was also triggered by changing weather patterns.  

Researchers at PICRC have said that, while the mass bleaching and subsequent damage to marine environments is something largely out of Palau’s control, actions such as temporary fishing closures in areas of badly-affected reefs could be taken to “boost” the recovery potential of corals.  

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