How much coral bleaching is in the Great Barrier Reef?
2020. The Great Barrier Reef experienced its most widespread bleaching event on record. Around 2,300 kilometres of coastal reefs were severely bleached, from the Torres Strait in the north, down to the Reef’s southern boundary.
How many bleaching events have occured in the Great Barrier Reef?
The Great Barrier Reef has experienced five mass bleaching events – 1998, 2002, 2016, 2017 and 2020 – all caused by rising ocean temperatures driven by global heating.
How did the Great Barrier Reef get bleached?
Coral bleaching is the process when corals become white due to various stressors, such as changes in temperature, light, or nutrients. Bleaching occurs when coral polyps expel the algae (zooxanthellae) that live inside their tissue, causing the coral to turn white.
Which coral reef is most affected by bleaching?
The Great Barrier Reef
The Great Barrier Reef experienced its most widespread bleaching event on record. Around 2,300 kilometres of coastal reefs were severely bleached, from the Torres Strait in the north, down to the Reef’s southern boundary.
How many coral reefs are affected by coral bleaching?
According to the National Oceanic and Atmospheric Association, between 2014 and 2017 around 75% of the world’s tropical coral reefs experienced heat-stress severe enough to trigger bleaching. For 30% of the world’s reefs, that heat-stress was enough to kill coral.
Can coral survive bleaching?
When water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white. This is called coral bleaching. When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality.
What does coral bleaching do?
Coral bleaching occurs when corals are stressed by a change in environmental conditions. They react by expelling the symbiotic algae that live in their tissues and then turn completely white. The symbiotic algae, called zooxanthellae, are photosynthetic and provide their host coral with food in return for protection.
What happens when coral is bleached?
Coral bleaching happens when corals lose their vibrant colors and turn white. But there’s a lot more to it than that. Coral are bright and colorful because of microscopic algae called zooxanthellae. If the temperature stays high, the coral won’t let the algae back, and the coral will die.
What happens to coral when it is bleached?
How often does coral bleaching occur?
Occurring at an average rate of once every 25–30 years in the 1980s, mass bleaching now returns about every six years and is expected to further accelerate…. Severe bleaching is now occurring more quickly than reefs can recover, with severe downstream consequences to ecosystems and people.