Reef systems near dominated by heat-tolerant species
By Summit Voice
FRISCO — Coral reefs are struggling to survive in many areas around the world, but some heat-tolerant species may have a refuge, at least for the next several decades, in the northern Red Sea, according to scientists with the Hebrew University of Jerusalem and Bar-Ilan University have found.
The researchers announced their finding by claiming that the coral reefs near the resort city of Eilat may have an advantage in the future over rival coral-viewing sites around the world.
At issue is the concern about coral reef bleaching, which typically occurs when seawater temperatures exceed the local summer maximum by one-half to one and half degrees Celsius. At those higher temperatures, the coral’s symbiotic algae are lost, leading to the coral’s bleaching and eventually its death.
Bleaching episodes have caused many reef systems around the world to deteriorate rapidly, but while the frequency of coral bleaching is globally increasing, no bleaching event has been observed in the Gulf of Eilat, even when conditions are conducive to bleaching.
The Israeli scientists explained the enigmatic lack of bleaching in the Gulf by the existence of a warm-water barrier at the southern Red Sea, allowing only heat-tolerant genotypes of corals to move north from the Gulf of Aden.
This occurred following the disappearance of corals from the Red Sea during the last glacial period, some 15,000 years ago. The scientists predict that no bleaching is likely to occur in the Gulf of Eilat/Aqaba in the next 100 years, making it a unique refuge for coral reefs in the world’s warming oceans.
That could be a bit of good news for regional biodiversity, which is, in part, due to the fringe of coral reefs in the Red Sea. The reefs are thought to about 5,000 to 7,000 years old, formed of stony acropora and porites corals, providing habitat for more than 1,200 species of fish, including more than 100 endemic species.