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Issue

Researchers have utilised a promising technique known as "coral IVF" to restore some of the damage to Australia's Great Barrier Reef.

 

Background

The Great Barrier Reef has lost more than half its coral in the past three decades due to global warming, pollution, and other threats to its long-term future.

 

Details

• The IVF technique sees the collection of coral sperm and eggs during the annual mass spawning event on the reef.

• These are then used to grow coral larvae in specially designed enclosures. After about a week, the larvae are distributed to areas of damaged reef in need of live coral.

• The tactic was first deployed just off Heron Island in 2016 and a survey carried out in subsequent months shows that the replanted coral is thriving with more than 60 new corals of varying sizes growing on the reef.

 

Coral Reef

• 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.

• Coral secrete hard carbonate exoskeletons that support and protect the coral. Most reefs grow best in warm, shallow, clear, sunny, and agitated water.

• Sometimes called rainforests of the sea, shallow coral reefs form some of Earth's most diverse ecosystems. They occupy less than 0.1% of the world's ocean area yet provide home to about 25% of marine species.

• Coral reefs flourish in ocean waters that provide few nutrients. They are most commonly found at shallow depths in tropical waters, but deep water and cold water coral reefs exist on smaller scales in other areas.

• Coral reefs deliver ecosystem services for tourism, fisheries, and shoreline protection.

 

Coral bleaching

When water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white. This is called coral bleaching.

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.

 

Other threats to Corals

 Coral reefs are fragile, partly because they are sensitive to water conditions. They are under threat from excess nutrients (nitrogen and phosphorus), rising temperatures, oceanic acidification, overfishing (e.g., from blast fishing, cyanide fishing, spearfishing on scuba), sunscreen use, and harmful land-use practices, including runoff and seeps (e.g., from injection wells and cesspools).

 

IVF

In vitro fertilisation is a process of fertilisation where an egg is combined with sperm outside the body, in vitro.