Great Barrier Reef

Context:

The highest levels of coral cover, within the past 36 years, has been recorded in the northern and central parts of Australia’s Great Barrier Reef (GBR), according to the annual long-term monitoring report by the Australian Institute of Marine Science (AIMS).

Relevance:

Environment and Ecology (Conservation of Environment and Ecology, Environmental Pollution and Degradation)

Dimensions of the Article:

1. Great Barrier Reef
2. About Coral Reefs
3. What does the new report say?

Great Barrier Reef

• The Great Barrier Reef, located in the Coral Sea (North-East Coast), off the coast of Queensland, Australia, is the world’s most extensive and spectacular coral reef ecosystem composed of over 2,900 individual reefs and 900 islands.
• This reef structure is composed of and built by billions of tiny organisms, known as coral polyps which are tiny, soft-bodied organisms and their base which is a hard, protective limestone skeleton called a calicle, forms the structure of coral reefs.
• It was selected as a World Heritage Site in 1981.

About Coral Reefs

• Indonesia has the largest coral reef area in the world and the Great Barrier Reef of the Queensland coast of Australia is the largest aggregation of coral reefs.
• India, Maldives, Sri Lanka and Chagos have the maximum coral reefs in South Asia.
• Coral Reefs protect humanity from natural calamities acting as a barrier, provide revenue and employment through tourism and recreation and also provide habitats for fishes, starfish and sea anemones.
• Coral blocks are used for buildings and road construction, the lime supplied by corals is used in cement industries and coral reefs may also be used in jewellery.
• India has four coral reef areas:
  • Gulf of Mannar,
  • Andaman and Nicobar Islands,
  • Lakshadweep islands
  • Gulf of Kutch.

Risks and threats to coral reefs

• Due to anthropogenic activities such as coastal development, destructive fishing methods and pollution from domestic and industrial sewage.
• Due to increased sedimentation, over-exploitation and recurring cyclones.
• Coral diseases such as black band and white band due to infectious microorganisms introduced by the human population that live on the coastal regions.

What does the new report say?

• The annual long-term monitoring by AIMS began 36 years ago, and reefs are surveyed through in-water and aerial techniques.
• The report states that reef systems are resilient and capable of recovering after disturbances such as accumulated heat stress, cyclones, predatory attacks and so on, provided the frequency of such disturbances is low.
• The new survey shows record levels of region-wide coral cover in the northern and central GBR since the first ever AIMS survey was done.
• Coral cover is measured by determining the increase in the cover of hard corals.
• The hard coral cover in northern GBR had reached 36% while that in the central region had reached 33%.
• Meanwhile, coral cover levels declined in the southern region from 38% in 2021 to 34% in 2022.
• The record levels of recovery, the report showed, were fuelled largely by increases in the fast-growing Acropora corals, which are a dominant type in the GBR.
• Incidentally, these fast growing corals are also the most susceptible to environmental pressures such as rising temperatures, cyclones, pollution, crown-of-thorn starfish (COTs) attacks which prey on hard corals and so on.
• Also, behind the recent recovery in parts of the reef, are the low levels of acute stressors in the past 12 months — no tropical cyclones, lesser heat stress in 2020 and 2022 as opposed to 2016 and 2017, and a decrease in COTs outbreaks.

-Source: The Hindu