Alarming coral bleaching phenomenon detected in the Red Sea

The Israel Nature and Parks Authority (NPA) said on November 5 that its researchers and marine ecologists have discovered a serious coral bleaching phenomenon in the Gulf of Aqaba, located in the northern Red Sea, off the coast of Eilat (Israel).

In the journal Ecology and Environment, scientists from the NPA and the Interuniversity Institute for Marine Research in Eilat published research results showing that for the first time in history, corals in the Gulf of Aqaba lost their natural color due to record-high sea temperatures last summer. This was a direct result of the extreme heat wave, when water temperatures reached 31.9 degrees Celsius, with daily maximum temperatures exceeding 30 degrees Celsius for two consecutive summer months.

Coral at Egypt's Ras Mohamed reserve on the Red Sea. (Photo: AFP/VNA).

Coral bleaching does not mean immediate death of corals, but it does leave them vulnerable and can eventually die because they are unable to carry out photosynthesis due to the disruption of their symbiotic relationship with the zooxanthellae microalgae that live inside the coral. When water temperatures exceed a dangerous threshold, this symbiosis is disrupted, causing the algae to be expelled from the coral. This reduces the coral's ability to survive and weakens the otherwise rich and diverse marine ecosystem.

Corals in the Gulf of Aqaba have long been known to withstand higher-than-average water temperatures, thanks to centuries of natural selection, according to researchers . The Gulf of Aqaba's location at the Bab el-Mandab Strait, the gateway between the Red Sea and the Indian Ocean, has helped corals there develop a greater tolerance to higher temperatures than other areas of the world. But what's worrying is that this past summer, Eilat's coral reefs experienced cumulative temperatures 3.75 times higher than the threshold for severe bleaching events on other reefs around the world.

This means that while the corals in the Gulf of Aqaba are naturally resilient, the sudden increase in temperature has exceeded the limits they can withstand. This is an alarming sign, as it shows that despite their long-term adaptation, these reefs are not completely immune to climate change.

The Israel Nature and Parks Authority (NPA) has now begun conducting surveys to assess the extent of coral bleaching and monitor the recovery and mortality of affected reefs. This will provide important data for scientists to develop measures to protect and restore the marine environment against the impacts of climate change.

The Red Sea, especially the Gulf of Aqaba, has long been known for its rich marine ecosystem, home to many unique marine species. However, uncontrolled temperature changes, especially extreme heat waves like this past summer, have had serious impacts on the survival of corals and other marine life.

These studies are not only a warning for the Red Sea, but also a worrying signal for marine ecosystems around the world. Climate change is gradually changing habitat conditions, putting corals and marine life at risk. Coral bleaching could be a sign of larger changes that affect the marine food chain, marine ecosystems, and even the industries that depend on these resources.