From: Dale Andersen's Astrobiology Field Reports
Posted: Thursday, March 1, 2012
This image of the large conical stromatolites in Lake Untersee was made using a Nikon D3s with a Nikkor 14-24mm lens inside a Subal Housing. Lighting was provided by two Sea & Sea YS-250 Pro strobes in manual mode. Credit: Dale T. Andersen
Three and a half billion years ago our planet was quite different and Earth's earliest biosphere was dominated by microbial communities - complex multicellular organisms were not to evolve for quite some time, only arriving on the scene about 600 million years ago. Those early ecosystems resulted in the formation of luxuriant microbial mats with a variety of morphologies which are seen today in the stromatolitic fossil record scattered around the globe. One of these morphologies was simply large cones, sometimes reaching heights of 2 meters.
Image: Lake Untersee, Antarctica (-71.34°, 13.448°) Gigapixel Image from the lake: Visit this link to view this immense panorama in all its glory. Credit: Dale T. Andersen
Detail from the Panorama: Astrobiologist Dale Andersen sits on a snowmobile while his camera system takes this expansive Gigpan panorama of Lake Untersee, Antarctica. Credit: Dale T. Andersen
Until recently, there have been no reports of modern microorganisms forming such structures, but in 2008 our research team discovered large conical stromatolites forming beneath the thick perennial ice of Lake Untersee. We made this discovery during the last few days of the expedition so we did not have time to make detailed observations.
However, in 2011 our research team returned to Lake Untersee to begin the first real studies of this incredible environment. This new high-quality image details the conical stromatolites that have formed on top of a boulder at a depth of about 20 meters, other cones can be seen populating the sloping bottom. The cones on the boulder are about 20 cm in height, but cones in other areas of the lake reach heights of a half a meter. We hope that our work at Lake Untersee and other similar lakes in Antarctica will help answer fundamental questions about life on early Earth - how do stromatolites form, and why do they make the cones, pinnacles, tenting, webbings and other morphologies observed in modern and ancient stromatolites?
Similar microbial communities may have evolved on Mars during a more clement (but still cold) period when liquid water was stable at the surface. Lakes or perhaps oceans, even if ice-covered could have provided an oasis for microbial life. Evidence for past life on Mars may therefore be preserved in the sediments and mineral precipitates associated with these past aquatic environments - the more we know about how life copes with similar constraints here on Earth, the better prepared we will be when some day, we are able to explore the ancient sediments of Mars.
You can support this research by visiting https://www.teamseti.org/supportdale
For more information, see: Andersen DT, Sumner DY, Hawes I, Webster-Brown J, McKay CP (2011) Discovery of large conical stromatolites in Lake Untersee, Antarctica. Geobiology, 9, 280-293. http://onlinelibrary.wiley.com/doi/10.1111/j.1472-4669.2011.00279.x/full
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