Context

Australia has downgraded the outlook for Great Barrier Reef to 'very poor' for the first time.

About

• The long-term outlook for Australia’s Great Barrier Reef was downgraded to “very poor” for the first time by the official agency charged with managing the world heritage site.
• The Great Barrier Reef Marine Park Authority singled out rising sea temperatures due to climate change as the biggest threat to the giant organism.
• However the threats to the 2,300-kilometre (1,400-mile) reef were "multiple, cumulative and increasing" and, in addition to warming seas; agricultural run-off and coral-eating crown of thorns starfish are the rising threats.
• If the condition of Great Barrier Reef continues declining, it may lose its world heritage status.
• The Great Barrier Reef, located off Australia’s East Coast is the largest coral reef in the world

What is a world heritage site?

• World Heritage Sites are cultural and/or natural sites considered to be of ‘Outstanding Universal Value’, which have been inscribed on the World Heritage List by the World Heritage Committee.
• These places or buildings are thought to:
  • have special importance for everyone
  • represent unique, or the most significant or best, examples of the world’s cultural         and/or natural heritage
  • Outstanding Universal Value is considered to transcend national boundaries and to be of importance for future generations.
    
    
• World Heritage status is a high accolade that brings with it responsibilities and international scrutiny.
• The United Nations Educational, Scientific and Cultural Organization (UNESCO) seek to protect and preserve such sites through the Convention Concerning the Protection of the World Cultural and Natural Heritage. This international treaty was drawn up in 1972.

Coral reefs

• Coral reefs are large underwater structures composed of the skeletons of colonial marine invertebrates called coral.
• The coral species that build reefs are known as hermatypic, or "hard," corals because they extract calcium carbonate from seawater to create a hard, durable exoskeleton that protects their soft, sac-like bodies.
• Hard corals rely on symbiotic algae (zooxanthellae) living within their tissues for nutrition and energy to build their skeleton.
• Soft corals look like colourful plants or graceful trees and are not reef-building since they do not produce the hard calcified skeleton of many reef-building corals.
• These types of corals are flexible organisms often resembling plants and trees and include species such as sea fans and sea whips
• These types of corals are flexible organisms often resembling plants and trees and include species such as sea fans and sea whips.
• Each individual coral is referred to as a polyp. Coral polyps live on the calcium carbonate exoskeletons of their ancestors, adding their own exoskeleton to the existing coral structure.
• As the centuries pass, the coral reef gradually grows one tiny exoskeleton at a time, until they become massive features of the marine environment.