Great Barrier Reef

In News 

• Recently, Australia unveiled a billion-dollar package to protect the climate-ravaged Great Barrier Reef .
  • It aims to prevent the vast network of corals from being removed from UNESCO’s World Heritage list.

Background 

• Earlier, UNESCO has decided to downgrade the status of the Great Barrier Reef in Australia because of its dramatic coral decline.
• Although the Report did commend Australia’s efforts to improve reef quality and its financial commitment.
• UNESCO has recommended that a total of 7 sites be added to the endangered list and that two sites – Liverpool’s waterfront and Selous game reserve in Tanzania, where poachers have run amok – be stripped of their World Heritage status altogether.
  • The List of World Heritage in danger is maintained in accordance with Article 11 (4) of the 1972 World Heritage Convention.
  • Inscribing a site on the List of World Heritage in Danger allows the World Heritage Committee to allocate immediate assistance from the World Heritage Fund to the endangered property.

Australia’s intiatives 

• When the UN previously threatened to downgrade the reef’s World Heritage listing in 2015, Australia created a Reef 2050 plan and poured billions of dollars into protection.
• The measures are believed to have arrested the pace of decline, but much of the world’s largest reef system has already been damaged.
• A 2021 poll by Sydney’s Lowy Institute found 60 per cent of Australians believed “global warming is a serious and pressing problem”.
• Australians are overwhelmingly in favour of action to limit climate change, having experienced a string of global warming-worsened disasters such as bushfires, droughts and floods.
• Eight in 10 Australians supported a net-zero emissions target by 2050, which the government reluctantly adopted ahead of a landmark United Nations climate summit in Scotland last year.

Coral Reefs

• A coral reef is an underwater ecosystem characterized by reef-building corals. 
• Reefs are formed of colonies of coral polyps held together by calcium carbonate.
• The coral polyps live in an endosymbiotic relationship with algae. Algae provides up to 90 per cent of the coral’s energy.
• Temperature:
  • The temperature of the water should not be below 20°C. 
  • The most favourable temperature for the growth of the coral reefs is between 23°C to 25°C. 
  • The temperature should not exceed 35°C.
• Salinity: Corals can survive only under saline conditions with an average salinity between 27% to 40%. 
• Shallow Water: Coral reefs grow better in shallow water having a depth less than 50 m. The depth of the water should not exceed 200m.
• Coral reefs are divided into four classes: 
  • fringing reefs, 
  • barrier reefs, 
  • atolls, and 
  • patch reefs. 
• Fringing reefs are the most common type of reef that we see.

Significance

• Coral Reefs provide an important ecosystem for life underwater, protect coastal areas by reducing the power of waves hitting the coast, and provide a crucial source of income for millions of people.
• Coral reefs have an estimated global value of £6 trillion each year, due in part to their contribution to the fishing and tourism industries and the coastal protection they provide.
• More than 500 million people worldwide depend on reefs for food, jobs and coastal defence. 
• Extracts from animals and plants living on reefs have been used to develop treatments for asthma, arthritis, cancer and heart disease.
• Coral reefs provide biodiversity: 
  • Thousands of species can be found living on one reef. 
  • The Great Barrier Reef contains over 400 coral species, 1,500 fish species, 4,000 mollusc species and six of the world’s seven sea turtle species. 
  • The Coral Triangle – a coral-rich marine region in Southeast Asia that encompasses the waters between Indonesia, Malaysia, the Philippines and Papua New Guinea – is the most biologically diverse marine ecosystem on Earth. 

Challenges for Coral Reefs

• Physical damage or destruction from coastal development, dredging, quarrying, destructive fishing practices and gear, boat anchors and groundings, and recreational misuse (touching or removing corals).
• Pollution that originates on land but finds its way into coastal waters. There are many types and sources of pollution from land-based activities.
• Overfishing can alter food-web structure and cause cascading effects, such as reducing the numbers of grazing fish that keep corals clean of algal overgrowth. Blast fishing (i.e., using explosives to kill fish) can cause physical damage to corals as well.
• Coral harvesting for the aquarium trade, jewelry, and curios can lead to over-harvesting of specific species, destruction of reef habitat, and reduced biodiversity.
• A recent study found bleaching had affected 98 percent of the reef since 1998, leaving just a fraction of it untouched.

Threat of Coral Bleaching

• Coral bleaching occurs when coral polyps expel algae that live inside their tissues. 
• When corals face stress by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae zooxanthellae living in their tissues, causing them to turn completely white. 
• This phenomenon is called coral bleaching.
• Reasons:
  • The leading cause of coral bleaching is climate change. 
  • A warming planet means a warming ocean, and a change in water temperature – as little as 2 degrees Fahrenheit – can cause coral to drive out algae. 
  • Coral may bleach for other reasons, like extremely low tides, pollution, or too much sunlight.

Image Courtesy: the star

Way Forward

• The countries could act to improve water quality at the reef, which would increase its resilience to climate change.
• Make collaborative efforts to mitigate the global effects of climate change – warming seas and increasing sea levels etc.
• The government is  backing the health of the reef and the economic future of tourism operators, hospitality providers and Queensland communities that are at the heart of the reef economy.

Source: Newsonair