by Ilana Messika
Coral reefs in the Gulf of Eilat on Israel’s southern coast at the northern tip of the Red Sea are particularly resistant to global warming and could possibly be used one day to re-seed dying reefs in other parts of the world, according to a study by Israeli and Swiss scientists.
While the study found that the Gulf reefs exhibit resistance to high water temperatures and ocean acidification, both consequences of global warming, the scientists called on Israel, Jordan, Egypt and Saudi Arabia, the four countries that share the waters known also as the Gulf of Aqaba, to cooperate in order to protect the reefs from pollution and other man-made factors that could wear down their resistance.
In the study, the results of which were published recently in the journal Royal Society Open Science, scientists from Bar-Ilan University and the InterUniversity Institute of Marine Sciences in Israel, and from École Polytechnique Fédérale de Lausanne (EPFL) and University of Lausanne (UNIL) in Switzerland exposed corals of the species Stylophora pistillata to water chemistry and temperatures expected by the end of the century if global warming continues at its current rate.
“Under these conditions, most corals would probably bleach and have a high degree of mortality,” said EPFL scientist Dr. Thomas Krueger. “Surprisingly, these corals did very well – at the end of the six-month period, we measured multiple variables and most of them had actually improved.”
Coral reefs are dying on a massive scale around the world, mostly due to global warming. Rising ocean temperatures and levels of acidity cause frequent bleaching events, leading to the ultimate death of the coral. Only a third of Australia’s Great Barrier Reef’s ecosystem, the planet’s largest reef and a World Heritage Site, remains unbleached.
The scientists hope the local corals may provide the key to understanding the biological mechanism that leads to thermal resistance, or the weakness that underlies massive bleaching; and that perhaps, in the future, Gulf of Eilat reefs could even be used to re-seed deteriorated reefs further south in the Red Sea and around the world.
Prof. Maoz Fine of Bar-Ilan University’s Mina and Everard Goodman Faculty of Life Sciences and the InterUniversity Institute of Marine Sciences told Tazpit Press Service (TPS) that coral reefs are among the most diverse and productive ecosystems on the planet. According to Fine, coral reefs are home to a vast range of creatures, provide food, biologically active compounds used in pharmaceuticals, protect coasts against storm damage and constitute unique touristic attractions.
“The preservation of coral reefs is extremely important both ecologically and economically,” Fine said. “However, these ecowater systems are a dying breed throughout the world due to the effects of global warming. The unique genome of the reefs found in the Gulf of Aqaba suggests these reefs will likely be the last ones to survive,” Fine continued.
According to the study, coral reefs started recolonizing the southern part of the Red Sea only at the end of the last ice age by coming from the Pacific Ocean through the Gulf of Aden. At at the Bab al-Mandab Strait on the coast of Yemen, the southern entrance of the Red Sea, the thermal bottleneck with summer water temperatures rising to 30-32°C provided a selective barrier, allowing only highly resistant individuals to move north. Fine explained that this process, akin to natural selection, is the reason why the corals found nowadays in the Gulf of Eilat are coded with a “warm genome” which can resist high temperatures.
“The coral reefs of the Gulf of Aqaba provide us with the chance to still enjoy and benefit from reefs in the future but such an opportunity entails a greater responsibility,” Fine said.
“Egypt, Jordan, Israel and Saudi Arabia must create a joint protection program to remove all anthropogenic stressful conditions, such as local oil pollution, nutrients from fish farms or gardening herbicides, which effectively destroy this exceptional thermotolerance,” Fine warned.
