Do Our Coral Reefs Need a Sun Shield?

The coral bleaching which has affected reefs all over the world over the last few years represents the most serious incident of its kind the Earth has ever seen. Largely thanks to manmade climate change, 75% of coral reefs worldwide have been affected by bleaching in the last three years, with 25% of them being killed in the process.

As a results, environmentalists and researchers have been scrambling to find answers to the problem. While the long-term, ideal outcome would be to simply curb our carbon emissions and bring global warming under control, more stopgap solutions may well be needed in the interim. One of those could be the provision of an ultra-thin sun shield to protect at-risk reefs from the damaging strength of the sun’s rays.

A way of life under threat

Coral reefs face a lengthening list of threats, most of them manmade. In addition to problems posed by microplastic pollution, acidification of the oceans, oversaturation of the fishing industry and water quality degradation due to agricultural runoff, the biggest danger to their ongoing existence is undoubtedly the rising temperature of the Earth.

In warm waters, coral reefs are deprived of the photosynthetic algae which not only give them their unique colourations, but also sustain them with life. Once the algae migrate to cooler climes, the coral becomes whitened (hence the name bleaching) and, if separated from algae for too long a period, eventually dies.

Losing coral reefs would not only be disastrous in and of itself, but could also hold major repercussions for the wider marine world. As the most biodiverse ecosystems found anywhere on the planet, coral reefs take up only 1% of the ocean floor but foster 25% of its inhabitants. Clearly, their extinction must be avoided at all costs.

A wafer-thin solution

With the current wave of coral bleaching incidents showing no signs of stopping, it’s imperative that the human race finds an antidote to the problems we have caused – even if they are just stopgap ones. The Great Barrier Reef Foundation has thrown its weight behind a figurative sunscreen for the ocean, which is intended to reflect as much as 30% of sunlight and provide valuable protection for the reefs below.

50,000 times finer than a human hair, the layer is completely biodegradable and indeed is actually made of calcium carbonate – the very same material from which reefs are constructed. What’s more, it’s self-dispersing; tests in laboratory conditions found that application of the layer to one corner of a body of water 25 acres in size would results in its whole surface being protected within a single hour. Unfortunately, there are still teething problems. The tumultuous nature of oceanic waves and the often-muddy composition of the waters mean that the layer is unlikely to stay in place in real-world conditions for an extended period, but the short respite it can provide to coral reefs could be invaluable.

“It’s important to note that this is not intended to be a solution that can be applied over the whole 348,000 square kilometres of Great Barrier Reef – that would never be practical,” said Anna Marsden of the Foundation. “But it could be deployed on a smaller, local level to protect high value or high-risk areas of reef.”