Giant crater-filled reef discovered behind the Great Barrier Reef

The Great Barrier Reef in Whitsundays, Australia The Great Barrier Reef in Whitsundays, Australia Shutterstock
20 Sep
2016
Enormous structure found in the seabed between the Torres Straight and Port Douglas, could unlock the history – and future – of the Great Barrier Reef

They may just look like green blobs, but these computer-generated shapes confirm the existence of an enormous unseen reef system, hidden in the waters behind the Great Barrier Reef.

The extent of the life form was discovered using state-of-the-art 3D LIDAR equipment, which scanned the length of the Great Barrier Reef area to reveal thousands of square miles of ancient reef structures. ‘It was amazing – completely unexpected,’ says Mardi McNeil, marine geoscientist at the Queensland University of Technology. ‘I re-did the calculation several times to make sure it was right.’

Although parts of the structure had been documented by marine scientists in the 1970s and 1980s, it was McNeil’s research team that discovered it was 6,000 square kilometres in total. Three times the initial estimations. ‘The more we looked, the more vast it became,’ she says. ‘It was exciting to realise that we were the first scientists to see the bioherm seafloor in its true extent, and study the implications of its size and complexity.’

bioherms BlighReefLIDAR scan of the discovered structure on the sea floor (Image: McNeil, et al)

It was when the scans were rendered to higher resolutions that the donut shapes, or bioherms, began to appear. These holes, some ten metres deep and 300 metres across, were formed by a comparatively small species of algae that builds up sediment in layers over time. ‘The bioherms near the Great Barrier Reef are made by a living layer of the humble algae Halimeda, which produces the same limestone mineral as corals,’ explains McNeil. ‘They have some similarities with true reefs, though lack the solid rigidity.’

The discovery comes at a crucial time for the Great Barrier Reef, which in the last year has rode out mass bleaching events and continues to endure the long-term pressures of ocean acidification and pollution. Nonetheless, McNeil hopes that the bioherm structures will unlock secrets about the history of the true reef up top. ‘They may have much to tell us about the Great Barrier Reef’s early formation, at the end of the last ice age, just before the continental shelf was flooded by rising sea levels,’ she says. ‘It could show the change in oceanic waters, sea temperatures, and upwelling of nutrient rich waters into what is now the present day Great Barrier Reef lagoon.’

McNeil hopes the find will spur scientists to re-evaluate how much carbon is locked up between the two enormous life forms. Meanwhile, the bioherms’ fossil records could indicate how reef systems have responded to drastic environmental change in the past, hinting at the Great Barrier Reef’s precarious future.

Share this story...

Submit to FacebookSubmit to Google PlusSubmit to Twitter

Related items

Geographical Week

Get the best of Geographical delivered straight to your inbox every Friday.

Subscribe Today

Target Ovarian Cancer

EDUCATION PARTNERS

Aberystwyth UniversityUniversity of GreenwichThe University of Winchester

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

DOSSIERS

Like longer reads? Try our in-depth dossiers that provide a comprehensive view of each topic

  • The Nuclear Power Struggle
    The UK appears to be embracing nuclear, a huge U-turn on government policy from just two years ago. Yet this seems to be going against the grain globa...
    The Air That We Breathe
    Cities the world over are struggling to improve air quality as scandals surrounding diesel car emissions come to light and the huge health costs of po...
    Diabetes: The World at Risk
    Diabetes is often thought of as a ‘western’ problem, one linked to the developed world’s overindulgence in fatty foods and chronic lack of physi...
    National Clean Air Day
    For National Clean Air Day, Geographical brings together stories about air pollution and the kind of solutions needed to tackle it ...
    REDD+ or Dead?
    The UN-backed REDD+ (Reducing Emissions from Deforestation and Forest Degradation) scheme, under which developing nations would be paid not to cut dow...

MORE DOSSIERS

NEVER MISS A STORY - follow Geographical

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in NATURE...

Polar

Geographical’s regular look at the world of climate change. This…

Oceans

The effect of plastics on the world’s oceans is posing…

Geophoto

Camera technology may have come a long way since the…

Energy

The UK appears to be embracing nuclear, a huge U-turn…

Wildlife

Despite their high profiles, most of the world’s national animal…

Oceans

Asian countries are pledging to reduce the amount of land-based…

Geophoto

There’s a world of visual wonder beneath the waves but…

Energy

A short, summer eclipse in America has solar power generators…

Climate

A dramatic increase in dust storms across the western United…

Climate

Geographical’s regular look at the world of climate change. This…

Climate

A study from the Proceedings of the National Academy of…

Wildlife

It’s not just the bees that are disappearing. Insects across…

Oceans

Far beneath the waves, a race is unfolding to claim…

Climate

Compared to other types of carbon sink, seagrass in Kenya…

Geophoto

Who in their right mind wants to shoot with film…

Climate

Geographical’s regular look at the world of climate change. This…

Geophoto

Calling photographers passionate about capturing and sharing great images of…

Climate

Five experts weigh-in on the future of the Paris Agreement…

Oceans

Analysis into a killer whale found dead off the shores…

Geophoto

For the past ten years, the Chartered Institution of Water…