Israeli marine scientists find Eilat’s reef able to resist higher sea temperatures, meaning it would lend itself to becoming a nature reserve in future years.
By Zafrir Rinat | 08:29 28.08.13

The coral reef in the Gulf of Eilat can function as a nature reserve for coral over the next century since it is relatively resistant to the effects of global warming, according to a new study on how the region’s coral reefs will respond to climate change.

The study was published this week in the journal “Global Change Biology.” It was conducted at the Interuniversity Institute for Marine Sciences in Eilat by Dr. Maoz Fine of Bar-Ilan University and professors Hezi Gildor and Amatzia Genin of the Hebrew University of Jerusalem.

The study’s goal was to determine how a possible rise in sea temperatures due to global warming would affect local coral. Over the last two decades, there have been several cases of coral reefs dying in various places around the world due to a process known as bleaching. Scientists believe this process occurs when rising temperatures harm the algae that have a symbiotic relationship with the coral.

The algae supply a significant portion of the coral’s food, so when the algae are harmed, the coral’s food supply diminishes. Lack of food then damages the coral’s tissues, leading to bleaching.

Scientists believe that bleaching occurs whenever sea temperatures rise above a certain level.

Bleaching has already occurred at some locales in the Indian Ocean, and that ocean connects to the Red Sea, of which the Gulf of Eilat is an offshoot. The Eilat study therefore tried to see how local coral reefs would react to temperatures above this threshold.

The researchers conducted various experiments, including exposing five different species of coral to varying temperature conditions. They also tested other variables, including the state of the algae living on the coral.

In addition, they studied data on temperatures in the Gulf of Eilat that had been collected over the years, and used various models to analyze changes in the sea level and atmospheric conditions in both the Gulf of Eilat and the Red Sea.

They also conducted simulations on coral movements in both bodies of water.
Coral Bleaching.
Coral Bleaching.Petchrung (Aey) Sukpong

Based on all this, the researchers predict that temperatures in the Gulf of Eilat will rise to the threshold that produces bleaching by the end of the century. But their studies of the coral show that these corals are capable of surviving such temperature changes.

The researchers theorize that corals in the Red Sea and the Gulf of Eilat developed resistance to heat as a result of the unique conditions that prevailed there in the past. At one time, the Red Sea was cut off from the Indian Ocean. Thus, when these two bodies of water were reconnected, the Red Sea corals suddenly had to contend with higher water temperatures. This created a process of natural selection, and the species that survived were those with greater resistance to heat.

In the future, however, the researchers expect water temperatures to rise more in the Red Sea than they do in the Gulf of Eilat. So while the Red Sea corals are unlikely to survive, they believe the Gulf of Eilat corals will do so.

The researchers say their findings make it essential for the government to recognize the importance of preserving the Gulf of Eilat coral reef, so it will be there to survive after other coral reefs have disappeared or been seriously damaged. This requires stepping up efforts to prevent pollution, as well as preventing the coral from being broken by boats or visiting tourists.

They also propose studying the possibility of using the Gulf of Eilat as a refuge for other heat-resistant corals from other parts of the world, as these locales may experience more drastic rises in water temperatures that make it impossible for the corals to survive in their native habitats.