In news- Recently, Australia has confirmed that a wide stretch of the Great Barrier Reef has been hit by a sixth mass bleaching event.
Key updates-
- It is the fourth time in six years that such severe and widespread damage caused by warm sea temperatures has been detected.
- Only two mass bleaching events had ever been recorded until 2016.
- There are particular concerns that this bleaching event has occurred in the same year as a La Niña weather phenomenon.
- Typically in Australia, a La Niña brings cooler temperatures.
- Scientists are now fearful of the damage that could be caused by the next El Niño.
- The Great Barrier Reef Marine Park Authority has warned that water temperatures in parts of the reef had been up to 4 degree C above the March average.
What is Coral bleaching?
- 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 that live inside their tissue, causing the coral to turn white.
- 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.
- Warmer water temperatures can also result in coral bleaching.
- Other environmental pressures on the reef and its ecosystem include runoff, climate change accompanied by mass coral bleaching, dumping of dredging sludge and cyclic population outbreaks of the crown-of-thorns starfish.
About Great Barrier Reef (GBR)-
- The Great Barrier Reef is located in the Coral Sea, off the coast of Queensland, Australia and contains the world’s largest collection of coral reefs.
- This reef structure is composed of and built by billions of tiny organisms, known as coral polyps.
- It can be seen from outer space and is the world’s biggest single structure made by living organisms.
- It also holds great scientific interest as the habitat of species such as the dugong (‘sea cow’) and the large green turtle, which are threatened with extinction.
- It supports a wide diversity of life and was selected as a World Heritage Site in 1981.
- CNN labeled it one of the seven natural wonders of the world in 1997.
- The Queensland National Trust named it a state icon of Queensland in 2006.
A large part of the reef is protected by the Great Barrier Reef Marine Park, which helps to limit the impact of human use, such as fishing and tourism.
Source: BBC
