JERUSALEM, Nov. 5 (Xinhua) -- Israeli ecologists and marine researchers detected significant coral bleaching in the northern Gulf of Aqaba in the Red Sea, off the coast of Israel's southernmost city Eilat, the country's Nature and Parks Authority (NPA) said in a statement on Tuesday.
In a study published in the journal Ecology and Environment, researchers from the NPA and the Interuniversity Institute for Marine Sciences in Eilat revealed that, for the first time, corals in the bay lost their natural colors due to unprecedented high water temperatures caused by this summer's extreme heat.
The researchers noted that water temperatures reached 31.9 degrees Celcius during the summer, with maximum daily temperatures exceeding 30 degrees for two consecutive months.
Bleached coral is not dead but is more likely to die from starvation due to a disruption in its photosynthesis process.
According to the researchers, the bleaching event highlights the sensitivity and fragility of coral reefs, explaining that when water temperatures rise above a critical threshold, the symbiosis between the corals and the tiny zooxanthellae algae that live within them ceases, leading to the ejection of the algae from the corals.
Many previous studies have shown that corals in the Gulf of Aqaba are known for their unique natural resilience to increased seawater temperatures and the coral bleaching phenomenon that accompanies it, as a result of long-term selection processes in the Bab el-Mandab Strait, allowing only corals with high heat resistance to migrate from the Indian Ocean to the Red Sea.
The researchers found that the cumulative heat load experienced by the Eilat reefs during the summer was 3.75 times higher than the threshold that causes severe bleaching events in other reefs worldwide.
This means that, although the resilience of the Gulf of Aqaba's corals is unique, it turns out that there is a red line, which has been alarmingly crossed this time.
Following these findings, the NPA began conducting surveys to assess the extent of the phenomenon and the rate of recovery and mortality of the bleached corals. ■
