Saving the Great Barrier Reef

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Blue Linckia Starfish on the Great Barrier reef courtesy of Wikicommons
A giant clam on the Great Barrier reef courtesy of wikicommons

A sunshade to save the Great Barrier Reef.

This week the University of Melbourne released a new method to potentially save the Great Barrier reef, and it is basically a giant sunshade.

What is the sunshade made of?

The proposed sunshade to protect the Great Barrier reef from incident sunlight is made of calcium carbonate. Calcium carbonate can be found in your fridge in the form of eggshells but is also found on the Great Barrier reef in the form of coral.

While calcium carbonate in the film can react with carbon dioxide in the water to form a new compound called calcium bicarbonate or be synthesized into the coral itself, the film will be extremely thin – 50,000 times thinner than the human hair. Such a thin film will use nearly negligible amounts of calcium carbonate to impact the water or marine life.

How thin is 50,000 times thinner than the human hair? In terms of calcium carbonate, it is one molecule. The tested Great Barrier reef sunshade is a film of calcium carbonate that is a mere one molecule thick. 

The Great Barrier reef sunshade isn’t for the whole thing.

The Great Barrier reef is huge. It covers nearly 350,000 square kilometers. That is nearly 3x the size of England or half the size of Texas. Adding a sunshade on the whole Great Barrier reef would be impractical – even at a mere one molecule thick. Instead, this sunshade will be deployed in smaller areas along the reef in areas of critical bleaching.

How well does the sunshade work for coral on the Great Barrier reef?

Lab studies show that the one molecule thick calcium carbonate film that acts as a sunshade effectively reflects 30% of the incident light.

Why is the health of the Great Barrier Reef important?

The Great Barrier reef does more than just provide a barrier to the Australian coast from waves. It is the home to thousands of organisms. There are more than 3,000 varieties of coral growing on the Great Barrier reef that provides a home to more than 3,000 different species of mollusks, 1,500 species of fish, 1,500 species of jellyfish, and more than 30 types of whales and dolphins. 

The marine diversity of the Great Barrier reef is absolutely stunning. In addition, coral reefs help recycle nutrients into the ocean, providing the lowest members of the food chain with sustenance.

What is coral bleaching, and how does coral bleaching impact the Great Barrier reef?

Coral bleaching is often seen more as the ocean becomes increasingly warmer due to climate change. This warming effect causes corals to expel their algae and begin to turn white – hence the name coral bleaching. 

As the coral becomes more and more bleached it becomes under more stress and can die much easier. As the coral dies it can no longer recycle the oceanic nutrients or be a home for marine life. This reduction in marine life leads to a reduction in the gene pool of animals living near the reef, which means species can be wiped out easier.

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