Coral bleaching and initiative by Australia


Australia pledged Aus $500 million ($379 million) in new funding to restore and protect the Great Barrier Reef.This has highlighted the seriousness of the problem of coral bleaching.

What are coral reefs:

1)Coral reefs are large underwater structures composed of the skeletons of coral, which are marine invertebrate animals

2)Coral Reefs are also called the “rainforests of the sea”.

Importance of coral reefs:

1)Although coral reefs cover only about 1 percent of the ocean floor, they support around 25 percent of marine biodiversity and are critical habitats of the planet.

2)Reefs are also important for human beings – they support traditional small-scale fishing communities, generate revenue from ecotourism and in the past have reduced the impact of tsunamis and storms.

3)Coral reefs are one of the most dynamic and threatened ecosystems in India and their conservation is to be made an priority.

What is coral bleaching?

1)Coral reefs are very sensitive ecosystems,even slight changes in water temperature and salinity can lead to coral “bleaching” and even death.

2)Bleaching is when corals lose the highly productive algae (termed zooxanthellae) from their tissues due to stress from high sea temperatures and solar irradiation.

3)The algae and coral have a symbiotic relationship: the algae remove the coral’s waste products while the coral gives the algae a safe environment to live in, and provides compounds for photosynthesis. Without the algae, the coral no longer has a sufficient source of food, meaning that it essentially starves to death.

4)Bleaching in itself is not a new phenomenon, it was first recorded in 1911 in the Florida Keys, and is likely to have occurred, at local scales, throughout the last several millennia of global reef growth. What is completely new is this frequency of bleaching events.   

Reasons for coral bleaching:

1)Rise in sea temperature

2)Global Warming

3)Pesticide runoff from farms

4)Atmospheric pollution

5)Industrial run off

6)Ocean acidification

7)Alien species invasion

8)Coral mining


Ecological Impacts of bleaching:

1)Decline in marine species diversity

2)Reduced growth rates,decreased reproductive capacity and elevated mortality rates.

3)Land masses will be directly exposed to waves leading to a risk of erosion.

4)Changes in coral communities affect the species that depend on them

5)Overall decline in genetic and species diversity occurs when corals die as a result of bleaching.

Socioeconomic impacts of bleaching

1)Degraded coral reefs are not able to provide the ecosystem services on which local human communities depend.

2)Reefs damaged by coral bleaching can quickly lose many of the features that is important for the aesthetic appeal that is fundamental to reef tourism. Thus there is loss of revenue from tourism.

3)It can drive large shifts in fish communities. This results into reduced catches for fishers targeting reef fish species, which in turn impacts food supply and associated economic activities.

4)Coral reefs are a valuable source of pharmaceutical compounds. Degraded and dead reefs are less likely to serve as a source for important medicinal resources.

Great Barrier reef:

1)The Great Barrier Reef is the world’s largest and longest coral reef system, stretching for 2,300km from the tip of Cape York in the north to Bundaberg in the south in Australia.

2)It is home to over 1,500 species of fish, abundant marine life and over 200 types of birds, it’s also one of Australia’s greatest conservation successes.

3)It is a World Heritage Area since 1981 (the world’s first reef ecosystem to be recognised by UNESCO), it is highly protected and one of the best-managed marine areas on Earth.

4)It is one of the seven wonders of the natural world, and the only living thing that’s visible from space

5)Rise in sea temperatures and pollution in addition to bleaching have led to an explosion in the numbers of a creature called the crown-of-thorns starfish.The predator starfish feeds on corals by spreading its stomach over them and using digestive enzymes to liquefy tissue.                                

Steps taken by Australia

1)Canberra had previously committed more than Aus$2 billion to protect the site over the decade, but has been criticised for backing a huge coal project by Indian mining giant Adani nearby.

1)The Australian government has, in 2018, announced its largest-ever investment in the coral reef: over half a billion Australian dollars ($378 million).

2)The money will be used to counter water pollution, combat coral-eating starfish, increase public awareness, boost reef monitoring, and improve the environmental impact of surrounding businesses.

3)The funds will also be used to expand reef restoration efforts, including trialling new techniques that can breed corals resistant to high temperatures and light stress.

4)The bulk of the new funding has been earmarked to improve water quality by changing farming practices and adopting new technologies and land management.

5)The funds will also go towards working with farmers to prevent sediment, nitrogen and pesticide runoff into the reef.

6)The Government would also work with traditional Aboriginal owners and the tourist industry to protect the reefs.

Coral Reefs in India:

1)Coral reefs in India are mostly found in the Andaman and Nicobar Islands, the Gulf of Mannar, the Gulf of Kutch and the Lakshadweep Islands.

2)Recently, the Zoological Survey of India reported finding three “pristine” reefs off the coast of Sindhudurg in Maharashtra.

3)Many of India’s coral reefs are protected areas – the Gulf of Mannar, the Mahatma Gandhi Marine National Park and the Gulf of Kutch, for example, are marine national parks set up to preserve these fragile ecosystems.

4)Most of the coral reefs in India are of the fringing type but the Lakshadweep Islands are coral atolls.

Coral bleaching in India

1)The corals of Andaman and Nicobar Islands:

  Problem:They were severely affected by the 2004 Tsunami and have not yet fully recovered.   

  Other reasons for coral bleaching in these islands include unregulated tourism, fishing,

  marine pollution amongst others.

2)Coral in the Gulf of Kachchh region:

   Problem:Siltation and eutrophication due to developmental activities have been the major

   cause of bleaching of corals.

3)Corals of Lakshadweep islands:

  Problem:Periodic dredging for boat passage in the lagoons, amongst others, affect the

   health of corals in these coral islands.

4)Gulf of Mannar reefs

  Problem:They affected due to intense local activities like intensive fishing, illegal

harvesting of protected species which affects the ecological balance, pollution from

  boats, construction along the shores etc.

Way forward and steps to be taken:

1)Reduce overuse of fertilizers in farms.

2)Regulate tourism

3)Treat industrial effluents before discharging them into the sea.

4)Ban fishing and harvesting of protected species.

5)Regularly service and maintain fishing vessels so that they cause minimum pollution.

6)Create awareness among the coastal communities and enlist their support to protect coral reefs.

7)Monitor and minimise invasion of alien species.

8)Changing land use pattern along the coast.

9)Adopting eco friendly construction techniques along the coast.

10)De-silting of rivers to reduce sediment flow into the sea.

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