VOA常速英语:Scientist Finds Microbe Colony Under Half-Kilometer of Antarctic Ice

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Scientists in Antarctica have discovered a colony of microbes that appear to have lived for millions of years under an ice formation hundreds of meters thick.

The population under Taylor Glacier is another example of stretching the boundaries of where life can thrive.

Jill Mikucki led the international team that discovered life in a place without light or oxygen, in a briny solution so salty that it doesn't freeze even at 5 degrees below zero.

"As a microbial ecologist, geomicrobiologist, it's hard for me to imagine a place where life can't take hold," she said. "As long as there's energy there, you're bound to find life."

At the nose, or front, of Taylor Glacier is a well-known formation that sounds like something out of a horror movie: Blood Falls. But the red ice that gives Blood Falls its name didn't scare off Mikucki.

"It's a real intriguing curiosity, and the first time I saw it ... I knew that this rust or this stain on the glacier was due to iron. I thought about, 'Hmm, what microbes are there taking advantage of that energy source?'"

The briny water that discharges at Blood Falls comes from beneath the glacier. It flows out only intermittently, so it took Mikucki several years to collect a fresh, uncontaminated sample.

She thinks the water is an ancient saltwater lake, which got trapped 1.5 million or more years ago as the glacier advanced and covered it up, sealing it and all the microscopic life swimming around in it, under the ice.

"It's undergone some pretty dramatic change," she explained. "It lost all its sunlight. It became permanently cold and dark. It's very salty. It's concentrated seawater. And so, only the strongest survived."

The briny liquid that's been trapped under the glacier is rich in iron and minerals, and it supports what could be a very large ecosystem.

"There was one study where they did some ice-penetrating radar work, and they detected this anomaly in their data that suggested there was some liquid, and it's in a depression that's 80 meters deep, 80 meters below sea level. So it has a potential to be a pretty large lake, under ice that's 400 meters thick."

The bacteria that live down under Taylor Glacier are adapted to the extreme conditions, but they're not so exotic that they can't thrive in warmer environments, too.

"Some of these bacteria are incredibly resilient, and I can actually grow them on a petri dish in the laboratory. They tolerate the cold and can grow in it, but they'll do just fine at higher temperatures as well."

Well, all this is interesting, but a VOA reporter asked Mikucki exactly what's the point of studying an ecosystem full of microscopic life hundreds of meters beneath the Antarctic ice?

"We have a lot to learn from the microbes that survive in these kinds of environments and have adapted to these cold, low-energy systems. They're very efficient. I think they're fabulous systems to study."

Mikucki is a visiting fellow at Dartmouth College in New Hampshire. Her paper on the discovery of a cold, dark and very ancient colony of microbes was published April 17 in the journal Science.