Hidden Giant of the Indian Ocean: Extraordinary Coral Discovery Near the Cocos Islands
A remarkable coral formation stretching more than 1.5 kilometres along the outer reef of the Cocos (Keeling) Islands has been identified by researchers, making it one of the largest known coral colonies ever recorded.
Hidden beneath the waters of the remote Australian territory in the Indian Ocean, the enormous rose coral (Pachyseris) formation stretches 1.56 kilometres - roughly the equivalent of 100 buses lined up end-to-end.
The Coral Discovery lies between 14 and 65 metres below the ocean's surface and covers an estimated 56,940 square metres, an area larger than three MCG playing surfaces.
But perhaps most remarkably, the discovery has been more than 30 years in the making.
Local dive operator Dieter Gerhard first noticed the coral more than three decades ago. It wasn't until researchers began mapping the reef that they realised just how far the formation extended, and that what appeared to be separate sections could potentially form one enormous colony.
Led by Dr JP Hobbs from Adelaide University, alongside researchers from the Queensland Museum and James Cook University, the team spent months mapping the coral's extraordinary dimensions.
The formation was so extensive that Dr Hobbs repeatedly ran out of air before reaching its end, using GPS to mark his progress between dives. It ultimately took 12 dives to map the full 1.56-kilometre stretch.
The coral measures an average of 36.5 metres wide, with additional sections extending another 200 to 300 metres beyond the main formation.
And while its size alone is significant, scientists are now investigating another intriguing question: is this one giant living organism, or multiple coral colonies that have fused together over time?
Genetic testing is underway to determine the answer.
The discovery provides new insights into the remarkable marine biodiversity of the Cocos (Keeling) Islands, located approximately 2,750 kilometres north-west of Perth.
The research forms part of ongoing work to better understand the biodiversity and ecology of the Cocos (Keeling) Islands Marine Park, supported by funding from Parks Australia.
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