The widespread heat stress on the Great Barrier Reef, causing huge bleaching events among the corals, has been revealed in new satellite images.A map, shared by the NASA Earth Observatory, uses temperature data from satellites that show the sea temperature off eastern Australia on March 4. The anomaly also shows the difference in the average sea surface temperature between 2003 and 2014. The map shows just how much the temperatures around Australia's famous Great Barrier Reef has changed.
Heat stress on corals can trigger a process that causes the corals to expel their zooxanthellae, a type of photosynthetic algae which provides them with nutrients. These nutrients also give the corals their bright colors, which makes them so beautiful to behold.As the heat expels all these nutrients, the corals loose their color and they are left vulnerable.Bleaching can occur after four consecutive weeks of higher than usual sea temperatures.