The Great Barrier Reef is threatened by heat and storms

Photo:Pixabay

According to the Australian Institute of Marine Science two cyclones and flooding have caused mass bleaching. The survey covered nineteen reefs between Lizard Island and Cardwell from August to October and revealed 72% mortality on twelve reefs.

In one northern section of reef across the Cooktown-Lizard Island sector more than a third of the hard coral cover has been lost, the largest decline in 39 years of monitoring. Scientists say that hot weather and tropical cyclones Jasper and Kirrily are behind the dramatic decline.

Scientists are still collecting data on the condition of the southern part of the Great Barrier Reef. The results indicate a great vulnerability of the reef to bleaching events the frequency and intensity of which is increasing due to climate change.

The Great Barrier Reef stretches 2,300 kilometers off the northeast coast of Australia and is considered one of the richest habitats on Earth. It is home to several hundred corals, 1,600 species of fish, 133 species of sharks and rays, including thirty species of whales and dolphins.

Coral bleaching occurs when the water temperature rises and the coral expels microscopic algae known as zooxanthellae in order to survive. If high temperatures persist for a long time corals die.

This year is confirmed as the fifth mass bleaching in the last eight years. The fast-growing Acropora coral suffered the highest mortality this year. This fact reinforces the need for Australia to become carbon neutral as soon as possible. The plan is to reduce emissions by at least 90 percent below 2005 levels by 2035. Richard Leck head of oceans for the World Wide Fund for Nature said we are fast approaching a tipping point. The Great Barrier Reef can heal but its resilience has limits.

Source:AlJazeera/Editorial