Scientists discover five submerged "Apostles" near iconic Australian landmark

Australian scientists have discovered five new, submerged "Apostles" -- limestone columns -- near one of Australia's most visited tourist landmarks, the Twelve Apostles.

Five limestone sea stacks, coined the "drowned Apostles," have been found 50 meters underwater and six kilometres away from the original Apostles site, on Victoria' south coast.

The submerged stacks, which stand four to six meters in height, are believed to be 60,000 years old, according to University of Melbourne researchers.

The Twelve Apostles, along Victoria's Great Ocean Road, is among Australia's greatest natural marvels.

The picturesque cluster of stand-alone boulders, which stand approximately 30 to 40 meters tall, were nicknamed the Twelve Apostles in the 1920s, despite the fact that only nine were visible.

After losing one of the nine Apostles in a dramatic collapse in 2005, the landmark has managed to boost its portfolio by five following the latest underwater find.

Associate Professor David Kennedy from the University of Melbourne's School of Geography said it was the first time linear stacks of limestone had been detected on the seafloor.

"From a scientific perspective, how do they even exist?" Kennedy, who supervised the research, told the Australian Broadcasting Corporation (ABC) on Thursday.

"Sea stacks are really transient features on the coastline, we only see them because the coast is eroding and they're constantly falling down.

"No one ever thought that they could be preserved over thousands of years with sea levels, (so) they've never been described anywhere else in the world."

Melbourne University PhD student Rhiannon Bezore, who made the discovery by using sonar data of the surrounding seafloor, said a number of critical environmental factors had to be present to shape the sea Apostles.

"The main factor is that through the past geological changes, sea levels have risen at such a fast pace," Bezore told the ABC on Thursday.

"Because of that, they've actually been submerged before erosional processes could come and knock them over."

In Bezore's study, published in the Journal of Coastal Research on Thursday, she also established that the original cliffs were eroding at a rapid pace of around 30 centimeters annually. Endit