Ellesmere Island (July 31/06) - Not too far from Eureka, but far from almost everywhere else, there's a yellow stain on a glacier that smells like rotten eggs.

That might sound like something to be avoided, but the sulphur springs on Ellesmere Island have been luring Canadian researchers for years, and has now drawn the attention of scientists at NASA's Jet Propulsion Laboratory.

The foul-smelling springs might just be the only ones of their kind this side of, well, Jupiter.

Bacteria live in the springs, which are similar to springs found on one of Jupiter's moons, Europa. That moon is also covered in ice, which is why NASA scientists are so interested in it, and in the Ellesmere sulphur springs.

The sulphur springs are glacier water full of sulphur, gypsum and calcite that bubbles up through the ice year-round.

"One of the key issues for Europa, why it's a high priority, is if you have water there's the potential to have life so what the hope would be is that there's some way to detect signs of life," said Stephen Grasby, a geologist with the University of Calgary who led the research team.

The team of four scientists hope their work at the site will develop ways to detect from a distance the bacteria that live in such springs. Samples collected during the two-week project are still in the lab, so it isn't yet known if the NASA scientists have found what they were looking for.

But with the U.S. government considering funding for a space mission to Europa, the Ellesmere expedition gives scientists a better idea of what to look for when they get a chance to study the distant moon up close, said Bruce Betts, director of projects for the Planetary Society, which helped fund the project.

"One of those key questions will be whether sulphur-rich vents on Europa show evidence of organics, a sign that life might have developed beneath Europa's icy crust," he said in a news release.

For Grasby, Europa holds the best chance of answering the big question of human existence.

"The whole point of Europa exploration is to hopefully deal with that everlasting question of 'are we alone in the universe?'"

As a geologist, Grasby is also interested in the springs for what they reveal about the nature of permafrost. For example, the spring appears to flow up through the glacier year-round.

"It's telling us that we know much less about ... water and permafrost than we thought we did," he said.