a shadow biosphere: life as we don't know it

on timesonline:

'mono lake has a bizarre, extraterrestrial beauty. just east of yosemite national park in california, the ancient lake covers about 65 square miles. above its surface rise the twisted shapes of tufa, formed when freshwater springs bubble up through the alkaline waters.

felisa wolfe-simon, a geobiologist, is interested in the lake not for its scenery but because it may be harbouring alien life forms, or “weird life”. mono lake, a basin with no outlet, has built up over many millennia one of the highest natural concentrations of arsenic on earth. dr wolfe-simon is investigating whether, in the mud around the lake or in the water, there exist microbes whose biological make-up is so fundamentally different from that of any known life on earth that it may provide proof of a shadow biosphere, a second genesis for life on this planet.'

and

'dr wolfe-simon has theorised that there may be life that chose an “evolutionary pathway” to utilise arsenic. if such microbes existed, it could suggest that life started on our planet not once but at least twice. in turn this would help to support the idea that life is much more likely to have started elsewhere in the galaxy.'

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