A diver near the Drowned Apostles, 50 metres below the ocean's surface. Supplied: Liz Rogers

A diver near the Drowned Apostles, 50 metres below the ocean’s surface.
Supplied: Liz Rogers

Twelve Apostles stacks 17

According to media reports Friday, scientists studying the Twelve Apostles in Victoria have discovered five previously unknown limestone stacks underwater.

Dubbed the Drowned Apostles, the surprise find means there has in fact been 17 of the columns in the ocean off the Great Ocean Road, Fairfax Media reports.

The newly-discovered stacks are four to six metres high and below 50m of water 6km off the coastline between Point Campbell and Peterborough.

Though they’re covered in coral and other sea life, they are the only known limestone columns to remain preserved in the ocean.

Melbourne University PhD student Rhiannon Bezore discovered the estimated 60,000-year-old stacks while investigating sonar data.

“They looked suspiciously like sea stacks and I literally did a double take,” she told Fairfax Media.

“This is kind of a first because sea stacks are really temporary features that exist more on a centuries time scale.

“The fact that they were spotted or exist, even, is pretty surprising.”

The drowned Apostles and the eight remaining of the Twelve Apostles would all originally have made up the same limestone coastline

The discovery promises to unearth a fresh perspective on life beneath the ocean.

Associate Professor David Kennedy from the University of Melbourne’s School of Geography said the high-resolution sonar data would allow researchers to investigate unchartered territory.

“People are only now with the technology being able to see the bottom of the sea floor in this detail,” he said.

“It’s almost like seeing an aerial photograph or looking at Google maps for the first time.

“So what we’ve really shown is how complex it can be, because these drowned landforms are also the habitats for a lot of our fish, lobsters and abalone.”

He said the unlikely boost in numbers could one day see tourists visiting the Seventeen Apostles.

“We’d have to wait a few hundred thousand years for us to go into an ice age though,” he said with a laugh.

“I’d like to think it could become a tourist attraction in and of itself — in fact, a couple of weeks ago we had a couple of technical divers actually dive on top of them.

“On the sea floor there’s more of these features, and if you get down and look at them, they would be a similar type of view to what you see today.

“It really adds something to the experience when you can look at the Twelve Apostles.”

The findings have been published in the US-based Journal of Coastal Research, and offer a novel insight into the complexity of Australia’s sea floor.