The super-corals of the Red Sea
Red Sea corals’ heat tolerance offers hope for climate crisis
- Reefs from Gulf of Aqaba in the Red Sea survived rise of seven degrees, say marine scientists
- A “bleached” coral is a stressed-out coral that, when triggered by environmental changes such as pollution and warming waters, has evicted its beneficial, energy-producing algae. Without these symbiotic algae, the coral loses its colour and appears white.
- Recovery from bleaching can be possible, but it’s not guaranteed.
- More frequent bleaching events mean less time for the corals to bounce back. Those that don’t recover, die – and their ecosystem can collapse with them.
Red sea corals
- Despite sea temperatures rising faster [in this region] than the global average rate, no mass bleaching events have occurred in the northern Red Sea
- Typically, a 1-2C increase beyond the summer maximum temperature would cause corals to dispel their algae
- But red sea corals easily withstood 4-5C above the current summer maximum. Some have even survived as much as 7C above the summer maximum.
- Not only are these corals proving resilient, but actually appear to do better in warmer waters. In some cases, their symbiotic algae doubled the amount of oxygen they produced and showed a 51% increase in primary productivity.
- During the last ice age – two and a half million years ago – sea levels fell and the Red Sea was cut off from the Indian Ocean, becoming intensely dry and salty.
- Then when the ice caps melted, the region reflooded.
- Over generations, as corals migrated into the Red Sea, passing a bottleneck in the south where temperatures reach average highs of 34°C every summer to the very north where temperatures drop to 16°C in winter, they adapted to the extremes in temperature and transported their newly acquired heat resilience with them.