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WORLD FOCUS: Lake Untersee

November 28, 2011
FRANK SHATZ
Dale Andersen, of Lake Placid, a biology graduate of Virginia Tech, who became a senior scientist at the SETI Institute’s Carl Sagan Center for the Study of Life in the Universe, made a name for himself while doing research on microbial ecosystems in extreme environments, such as areas of the Artic, Antarctic, Atacama Desert, Death Valley and Siberia.

He followed in the footsteps of his former professor and mentor at Virginia Tech, George Simmons, who led many of the early discoveries within the lakes of Antarctica’s McMurdo Dry Valleys, including discovering the luxuriant benthic microbial mats living beneath the ice and first studies of groundwater influx within the lakes. Later, Simmons and his colleagues, including some from the William & Mary-affiliated VIMS, made the connection with nitrogen influx into the Chesapeake Bay via groundwater. It was a new approach to looking for sources of nutrients that lead to eutrophication, a process of receiving excess nutrients that stimulates excessive plant growth that, in turn, can cause other organisms to die.

Andersen is now engaged in deep-water research in an Antarctic lake that promises to shed light on how microbial ecosystems evolved on early earth.

He writes in his Blog: “In just under a month I will begin my journey back to the mountains of Queen Maud Land in Antarctica to revisit one of the most fascinating and wonderful places on the planet - Lake Untersee”.

In 2008, with the Tawani International Antarctic Expedition, he spent almost two months there. During the last week of the expedition, they made what Andersen calls, “the single-most important observation.” It was the discovery of large conical stromatolites, growing on the bottom of the lake.

“As far as we know, these are the only modern analogs to similar microbical structures that formed as far back as 3.45 billion years, the dawn of life on our planet,” he writes. “The image of the modern stromatolites is one I captured while diving beneath the ice and it shows several things: the water is stunningly clear, the bottom is pretty dynamic with hills and valleys, and is covered in a rich, luxuriant benthic microbial mat composed of primarily cyanobacteria and heterotrophic bacteria.”

He continued, “But the most interesting aspect of the image are the large, conical stromatolities that are reaching upward from the bottom of the lake ...In the Antarctic setting, devoid of larger metazoans - there are no fish, no insects, no worms, or crustaceasns or other multicellular organism that would otherwise disrupt the microbial mat communities and destroy their various morphologies. What compels a colonial collection of microorganism to construct the various macro-scale forms we observe in the ancient record as well as modern? We really don’t know. This is one of the fascinating questions we are seeking to answer by studying these polar analogs to their ancient cousins that were proliferate on early Earth.”

The results of Andersen’s research triggered a series of articles in scientific journals.

ScienceNews, in a piece headlined “Antarctic lake hides bizarre ecosystem,” noted,: “In the eerie bluish-purple depth of an Antarctic lake, scientists have discovered otherwordly mounds that tell tales of the planet’s early days. Bacteria slowly built the mounds, known as stomatolites, 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 scientist 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, one of Andersen’s colleague’s.

Braving the frigid waters of Lake Untersee, to see and study the bacteria-built stromatolites, Andersen, who has dived into more than eight such lakes in search of primitive life-forms, was quoted saying,”These are just incredibly beautiful microbial landscapes. The discovery of the stromatolites rocketed East Antarctica’s Lake Untersee to the top of my list.”

More: Dale Andersen’s, website and blog is accessible at HYPERLINK “http://bit.ly/pvTM04” http://bit.ly/pvTM04 with a link to a site for donation to support Lake Untersee research.



Frank Shatz lives in Williamsburg, Va. and Lake Placid. His column was reprinted with permission from The Virginia Gazette.
 
 

 

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