Hotspot volcanoes

Newly discovered underwater volcanoes could be a biological hotspot •

A research expedition led by Australian National University (ANU) has discovered a ‘lost ocean world’ of underwater volcanoes about 250 miles off the coast of Tasmania.

The scientists were aboard the Commonwealth Scientific and Industrial Research Organization (CSIRO) research vessel Investigator mapping the seafloor when they came across the previously unknown seamount chain.

The volcanic mountains rise up to 3 km above the surrounding ocean floor, with the highest peaks reaching about 2 km from the surface of the water.

“This is a very diverse landscape and will no doubt be a biological hotspot that is home to a dazzling array of marine life,” said CSIRO team member Dr Tara Martin.

“Our multibeam mapping has revealed for the first time in vivid detail a chain of volcanic seamounts rising from an abyssal plain at around 5000m depth.”

According to Dr. Martin, the volcanic towers vary in shape and size, from sharp peaks to wide flat plateaus covered in tapering hills resulting from ancient volcanic activity.

“Having detailed maps of these areas is important to help us better manage and protect these unique marine environments, and provides a springboard for future research,” she explained.

Across the mountain range, researchers detected peaks in ocean productivity, including elevated phytoplankton activity.

Dr. Eric Woehler from BirdLife Tasmaniawho was monitoring seabirds and marine mammals on the expedition, was amazed by the amount of marine life in and around the volcanic seamounts.

“While we were above the chain of seamounts, the ship was visited by large numbers of humpback and longfinned pilot whales,” said Dr Woehler. “We estimated that at least 28 individual humpback whales visited us one day, followed by a group of 60-80 long-finned pilot whales the next.”

“We also saw large numbers of seabirds in the area, including four species of albatrosses and four species of petrels. Clearly, these seamounts are a biological hotspot that supports life, at the both directly on them, as well as in the ocean above.

Dr Woehler explained that seamounts can be an important landmark for humpback whales as they migrate from their winter breeding grounds to their summer feeding grounds.

“Fortunately for us and our research, we parked just above this marine life highway!”

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

By Chrissy Sexon, Personal editor
Image credit: CSIRO