31 January 2013

"At the bottom of the world we can look through a window into our very distant past"

...Cyanobacteria are resourceful organisms. They produce their own energy using a photosynthesis process similar to plants. Light penetrates through the ice cover and through the water down to the lake floor where the microbes grow. Because of a lack of predation and a lack of disturbance by larger organisms, these microbes grow rampant over any surface that is hospitable for growth (in this case any depth that light can reach).
This type of microbial growth is actually quite common in Antarctic and Arctic lakes. What makes Lake Untersee particularly special is that these microbes form two different types of structures – collections of millions of individuals growing together over thousands of years of layered development.

The microbes of Untersee form two distinct kinds of constructions – pinnacles and cones. Both the pinnacles and cones are types of microbial communities and represent one of the earliest forms of life, present in the fossil record nearly 3.5 billion years ago.

The pinnacles of our lake are small, between one-half inch and six inches tall and dominated by a Leptolyngbya species that is common in Antarctica. The other structures, found nowhere else on present-day earth, are the conical stromatolites. The microbes covering the cones aren’t very thick, roughly half a millimeter, but the dark purple cones can grow higher than one and a half feet. These cones consist predominately of a Phormidium species, and it’s thought that the different microbial species are somehow responsible for the creation of the different structures...
-- Michael Becker

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