In the eerie bluish purple depths of an Antarctic Lake, scientists have discovered otherworldly mounds, which tell stories of the planet's early days.
Bacteria slowly built the mounds known as Stromatolites, layer by layer on the Lake floor. The lump, which look like oversized traffic cones are similar to similar structures appeared billions of years and remain widespread in fossil form of one of the oldest records of ancient life. The Antarctic discovery could thus help scientists to understand the conditions under which primitive life forms thrived. "It's like that go back to the 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, California, describing the discovery in an upcoming issue of geobiology. "These are simply incredibly beautiful microbial landscapes", she says.
Researchers have explored many Antarctic Lakes, to study the strange and wonderful microbes that live there. Andersen alone has in at least eight such Lakes dived. But he says that the discovery of Stromatolites scored the East Antarctic Lake Untersee "at the top of my list."
Researchers examine fossil Stromatolites, of 3 billion years or more, to understand how got to life on Earth foot hold. Today, Stromatolites is active in only a few spots in the ocean, such as off the western coast of Australia and in the Bahamas. You grow other freshwater lakes in some fresh water environments such as super-salty lakes high in the Andes and in some of the Antarctic. But scientists have still never something like the size and shape, the Untersee's Stromatolites.
Drawn by his extremely alkaline water and high amounts of dissolved methane, drill-through of its permanent ice cover traveled Andersen and his colleagues in Untersee 2008 and collect water samples.
Andersen was used to mats bacterial growth in other Antarctic Lakes, but nothing like the large mounds, which he saw when he dipped under the ice at the Untersee to find. Up to half a meter high, occupied this purplish clusters of the Lake below like barnacles on a ship hull. "It completely us way blew," says Andersen. "We had never seen something, such as that."
Examples produced one of the mounds showed that it mainly from long, stringy cyanobacteria, old photosynthetic organisms. The bacteria can still each level in the Sumner Untersee build cold waters, says decades, so the mounds to collect can have taken thousands of years.
Oddly enough the Stromatolite mounds sat next to smaller, Pinnacle-shaped lump, which had seen researchers in many other lakes. And the Stromatolites were mostly from Phormidium bacteria, while the pinnacles of another group, Leptolyngbya have been made.
Sumner says something significant this sharp distinction between bacterial composition at various shaped lump of Untersee. "Everywhere, that we have a gradation between the structures," as in bacterial mats of spacious Yellowstone's hot springs, she says. "It is something very special to this particular example, which form this large conical Stromatolites."
But scientists are not sure yet what that something special is. Andersen's team has recently two other ice-covered Antarctic Lakes, Vanda and Joyce, without finding it studied large conical Stromatolites. Conditions vary from Lake, Lake, each of them on their own frigid way unique make. Lake Vanda, for example, has a transparent ice cover, which can penetrate more light. Lake Joyce has thicker ice, limits as far below photo synthetisierenden organisms can grow.
What distinguishes Untersee would help scientists, better to find out, the boundaries live today and in the long distant past. "It's developed, a real challenge for our understanding as these communities", says Ian Hawes, a polar ecologist at the University of Canterbury in Christchurch, New Zealand.
More answers should come this November Andersen team Untersee to return is scheduled to run up more samples that scratch ghostly blue mounds.
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