A new algorithm developed by KAUST researchers offers improved predictions for coral bleaching in the Red Sea, which could also be adapted to other tropical marine ecosystems. This method, built from over 30 years of satellite data, enhances the detection of extreme warming events that lead to coral bleaching, suggesting that such events may occur more frequently in the Red Sea than previously thought.

Corals expel the algae that provide them with energy when exposed to high sea surface temperatures for extended periods. This causes coral bleaching, and if the stress continues, it can result in coral death and the collapse of the reef ecosystem.

The Red Sea is known for having some of the warmest surface temperatures and heat-tolerant corals, but these corals are not well monitored, making it difficult to assess the true extent of the damage caused by rising temperatures. Traditional methods, such as the “degree heating weeks” approach, have overestimated or missed bleaching events in the region, especially during cooler periods.

KAUST’s researchers fine-tuned the method by adapting it to the specific environmental conditions in the Red Sea. Their new approach focuses on marine heatwaves, defined by sea surface temperatures in the top five percent for at least a week. They found that bleaching events were tied to these heatwaves, with temperatures of 30°C or higher. This suggests that coral bleaching in the Red Sea may have been significantly underestimated and indicates that the northern Red Sea, once considered a thermal refuge for corals, might not remain so for long.

The algorithm is being further refined for use in other tropical marine ecosystems, with plans to integrate it into the interactive Red Sea Atlas being developed at KAUST.

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