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

Leave a comment

ONLY registered members can leave comments and each comment is held pending authorisation before publishing. Please login or register to voice your opinion.

Geographical Week

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

Subscribe Today

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

  • 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...
    The true cost of meat
    As one of the world’s biggest methane emitters, the meat industry has a lot more to concern itself with than merely dietary issues ...
    Long live the King
    It is barely half a century since the Born Free story caused the world to re-evaluate humanity’s relationship with lions. A few brief decades later,...
    London: a walk in the park
    In the 2016 London Mayoral election, the city’s natural environment was high on the agenda. Geographical asks: does the capital has a green future, ...
    The Money Trail
    Remittance payments are a fundamental, yet often overlooked, part of the global economy. But the impact on nations receiving the money isn’t just a ...

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...

Wildlife

Aaron Gekoski continues working alongside the Wildlife Rescue Unit

Geophoto

Today, the camera is regarded as an essential smartphone feature.…

Oceans

An innovative new theory hopes to save millions of lives…

Wildlife

Aaron Gekoski continues his personal adventure into the wilds of…

Wildlife

Simple tracking devices have enabled conservationists to amass big data,…

Climate

In a new report, researchers have calculated the global emissions…

Climate

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

Wildlife

The latest episode sees ‘Bertie’ enlisting in wildlife rescue boot…

Energy

Icelandic engineers are attempting to harness the powerful geothermal energy…

Wildlife

New video series tracks the journey of Aaron Gekoski as…

Energy

Newly-developed ‘sustainable rubber’, produced using recycled food waste, could one…

Geophoto

This winter has seen frequent storms and flooding hitting many…

Wildlife

The bison, Poland’s symbol of nature conservation, already faces controversial…

Wildlife

Wolves have arrived at a wildlife park in Devon as…

Climate

An unassuming beach in Denmark is absorbing record-breaking levels of…

Energy

The environmental cost of military activities is significant. Could new…

Wildlife

Latest figures suggest that there are more than twice as…

Tectonics

How does the proposed allocation of ‘Zealandia’ as an independent…

Wildlife

Is extinction forever? While most would assume that yes, extinction…

Geophoto

Wide-angle photography is perhaps the best way to recreate the…