Researchers have discovered a volcanic “lost world” teeming with marine life off the coast of Tasmania.
A voyage led by scientists from the Australian National University uncovered the hidden region while conducting detailed seafloor mapping aboard a vessel operated by CSIRO (The Commonwealth Scientific and Industrial Research Organisation).
These investigations revealed, for the first time, a diverse chain of volcanic seamounts—or underwater mountains—located deep in the ocean around 400 kilometers (249 miles) east of the island. The highest of the seamounts reach up to 3,000 meters (9,842 feet) above the seafloor, yet their peaks still lie nearly 2,000 meters below the surface.
“Our multibeam mapping has revealed in vibrant detail, for the first time, a chain of volcanic seamounts rising up from an abyssal plain about 5,000 meters deep,” Tara Martin, from the CSIRO mapping team, said in a statement.
“The seamounts vary in size and shape, with some having sharp peaks while others have wide flat plateaus, dotted with small conical hills that would have been formed by ancient volcanic activity,” she said. “This is a very diverse landscape that supports a dazzling array of marine life.”
Data collected by the researchers show large spikes in ocean productivity over the seamount chain—a term that largely refers to the production of organic matter by single-celled plant organisms known as “phytoplankton.” The team also noticed a significant increase in observations of marine animals in these areas.
“While we were over the chain of seamounts, the ship was visited by large numbers of humpback and long-finned pilot whales,” Eric Woehler, a researcher from BirdLife Tasmania who was on the ship conducting seabird and marine mammal surveys, said in the statement.
“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,” he said.
“We also saw large numbers 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.”
Previous research has shown that seamounts are key stopping points for some migratory animals, particularly whales who use the features as navigational aids during their journeys.
“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,” Woehler said.
“Lucky for us and our research, we parked right on top of this highway of marine life!”
According to the researchers, mapping surveys such as these are important because they can help us to protect and manage these unique marine environments, while also providing a strong foundation for follow-up research.
The CSIRO ship, known as Investigator, will return to the region later this year for two more expeditions, in November and December, that will look into the life and origin of the seamounts by collecting rock samples and capturing video footage using high-resolution deep-water cameras.
“We expect that these seamounts will be a biological hotspot all year round, and the summer visit will give us another opportunity to uncover the mysteries of the marine life they support,” Woehler said.
The world’s oceans cover more than two-thirds of the Earth’s surface—but despite decades of scientific research, we still have vasts gap in our knowledge. In fact, estimates suggest humans have explored only five percent of the marine environment, according to figures from the National Oceanic and Atmospheric Administration.
A study published in March this year highlights this lack of knowledge. In the paper, researchers investigated a zone of the ocean in coral reef ecosystems where life is so different from the regions above and below that an entirely new category is required to describe it.
Meanwhile, another group of scientists has recently returned from an expedition aimed at investigating the mystery of why a population of great white sharks that normally live off the North American West Coast travels to a 160-mile-wide stretch of seemingly inhospitable ocean in the Pacific every year during the winter and spring.