Researchers working in the stormy waters off the coast of Antarctica say they have discovered an active underwater volcano.

After spending two weeks bashing their research vessel against severe sea ice, the frustrated marine scientists from the U.S. and Canada diverted to gentler waters.

Eugene Domack of Hamilton College in Clinton, N.Y., and his team interrupted their studies on why a massive ice sheet collapsed in 2001 to explore a suspected volcanic site on the northernmost tip of the continent.

Volcano stands 700 metres above seafloor

Historically, mariners had seen discoloured water in the area and scientists knew ash from underwater volanoes can discolour the water above them.

To confirm their suspicions, Domack and his colleagues used four types of instruments:

• A video camera recorded the bottom two metres of the sea floor behind the ship. As expected for an active volcano, there were patches with no underwater life.
• A basket dredged the sea floor, recovering bits of bedrock that were clearly volcanic based on their mineralogy and magnetic properties.
• Acoustic measurements showed what appeared to a rising column of bubbles.
• Sensitive temperature probes showed slight variations at the edges, suggesting geothermal heating.

The researchers said the volcano stands 700 metres above the seafloor and extends to within roughly 275 metres of the ocean surface.

The unnamed volcano is on a continental shelf, near a deep tough carved by glaciers. The barren patches and lack of glacial scours suggest it is relatively young.

It may be less than several tens of thousands of years old, said Queen's University geography Prof. Robert Gilbert, who was on the research cruise.

Gilbert's research focuses on the effects of global climate change in the Arctic but bipolar comparisons help scientists to interpret their findings, he said.