Eerie Antarctic lake

Eerie blue light suffuses the otherworldly bottom of Lake Untersee, Antarctica

In the eerie bluish-purple depths of an Antarctic lake, scientists have discovered otherworldly mounds that tell tales of the planet's early days.
Bacteria slowly built the mounds, known as stromatolites, layer by layer on the lake bottom. The lumps, which look like oversized traffic cones, resemble similar structures that first appeared billions of years ago and remain in fossil form as one of the oldest widespread records of ancient life. The Antarctic discovery could thus help scientists better understand the conditions under which primitive life-forms thrived. "It's like going back to early Earth," says Dawn Sumner, a geobiologist at the University of California, Davis.
Sumner and her colleagues, led by Dale Andersen of the SETI Institute in Mountain View, Calif., describe the discovery in an upcoming issue of Geobiology. "These are just incredibly beautiful microbial landscapes," she says.
Researchers have probed many Antarctic lakes to study the weird and wonderful microbes that live there; Andersen alone has dived into at least eight such lakes. But he says the discovery of the stromatolites rocketed East Antarctica's Lake Untersee "to the top of my list."
Researchers study fossil stromatolites, from 3 billion years ago or more, to understand how life got a foothold on Earth. Today, stromatolites actively form in only a few spots in the ocean, like off the western coast of Australia and in the Bahamas. They also grow in some freshwater environments, like super-salty lakes high in the Andes and in a few of Antarctica's other freshwater lakes. But scientists have never seen anything like the size and shape of Untersee's stromatolites.
Drawn by its extremely alkaline waters and high amounts of dissolved methane, Andersen and his colleagues traveled to Untersee in 2008 to drill through its permanent ice cover and collect water samples.

Source: Science News