Incredible lost world of underwater volcanoes found east of Tasmania

AN incredible stretch of massive underwater volcanoes, which also serves as a ‘superhighway’ for migratory whales, has been discovered off the east coast of Tasmania.

A LOST world of underwater volcanoes found during a voyage off the east coast of Tasmania has left experts astonished at the amount of bird and marine life in the area — to the point where it’s been touted as a “whale superhighway”.

The incredibly diverse chain of volcanic seamounts about 400km off east Tasmania was found by the CSIRO vessel Investigator during detailed sea floor mapping.

Mapping of the volcanic seamount chain found off the east coast of Tasmania by the CSIRO vessel Investigator. Picture: CSIRO

Videos provided by CSIRO show the staggering height of some of the ocean mounts — some of which tower up to 3000m from the sea floor.

Despite this, the CSIRO says the highest peaks were still sitting deep under the sea, at nearly 2000m below surface level.

Underwater seamounts found off the coast of Tasmania by CSIRO vessel Investigator. Picture: CSIRO

CSIRO mapping team’s Dr Tara Martin said the find offered a window into a previously unseen and spectacular underwater world.

The mapping uncovered more than a dozen large seafloor features. It’s thought the seamounts were formed by ancient volcanic activity when this part of the Earth’s crust was sitting on top of a hotspot in the mantle. The hotspot melted the Earth’s crust above, forming the volcanoes.

“Having detailed maps of such areas is important to help us better manage and protect these unique marine environments, and provides a stepping stone for future research,” Dr Martin said.

“This is a very diverse landscape and will undoubtedly be a biological hotspot that supports a dazzling array of marine life.”

Data collected by the Investigator shows spikes in ocean productivity over the chain of seamounts, with an increased amount of phytoplankton (microscopic algae which provide food for an array of sea creatures — including whales, snails and jellyfish).

The findings indicate the area could be a vital stopping point for some migratory animals — particularly whales. The research team suspects whales are using the sea floor features as a navigational tool during their migration.

Humpback whales found in the area where a lost world of volcanic seamounts were discovered off the coast of Tasmania. Picture: Eric Woehler

BirdLife Tasmania’s Dr Eric Woehler, who was on the Investigator, said he was astounded by the amount of marine life they saw in the area.

“While we were over the chain of seamounts, the ship was visited by large numbers of humpback and long-finned pilot whales,” Dr Woehler said.

“We estimated that at least 28 individual humpback whales visited us on one day, followed by a pod of 60-80 long-finned pilot whales the next.

Humpback whales found in the area where a lost world of volcanic seamounts were discovered off the coast of Tasmania. Picture: Eric Woehler

“These seamounts may act as an important signpost on an underwater migratory highway for the humpback whales we saw moving from their winter breeding to summer feeding grounds.

“Lucky for us and our research, we parked right on top of this highway of marine life!”

Dr Woehler said the team also observed a large amount of seabirds in the area, including four species of albatross and four species of petrel.

“Clearly, these seamounts are a biological hotspot that supports life, both directly on them, as well as in the ocean above,” he said.

A black browed albatross found where a lost world of volcanic seamounts were discovered near Tasmania. Picture: Eric Woehler

A southern giant petrel found where a lost world of volcanic seamounts was discovered off Tasmania. Picture: Eric Woehler

In November and December the Investigator will return to the ‘lost world’ to further study the life and origin of the seamounts.

The researchers will collect rock samples to detemine the age of the seamounts and how long they took to form and they will also conduct a detailed study of marine life in the area.

They’re also hoping for answers as to how mantle hotspots played a role in the breakup of Tasmania and Antarctica.

Dr Woehler said he expected further surprises on the return visits.

“We expect that these seamounts will be a biological hotspot year round, and the summer visit will give us another opportunity to uncover the mysteries of the marine life they support,” he said.

The Investigator is Australia’s only research vessel dedicated to bluewater research. The vessel conducts research year round.

Australia has a vast marine estate, the third largest in the world, but only about 25 per cent of it has been mapped in detail.

Every time the ship sails on a voyage it maps a little bit more of the seafloor.