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Saturday, October 30, 2010

The hunt for extremophiles in Lake Untersee

In early 2008, a team of NASA scientists left the United States for Antarctica to explore one of the strangest lakes on our planet: Lake Untersee. This body of water is fed by glaciers and permanently shielded by an ice layer, however, what makes it particularly interesting to scientists is its basicity. Lake Untersee is extremely alkaline, with a pH comparable to that of extra-strength laundry detergent. Additionally, the lake’s sediments produce more methane than any other natural body of water on Earth, and thus, if life in any form is found in these waters, the implications will be unbelievable. This should sound familiar to us: Predominantly icy areas? The presence of liquid methane? These are the exact same sort of characteristics possessed by the exotic planets that we talked about in class a couple weeks ago. The icy moons of Jupiter (Europa, Io) and Saturn (Titan, Enceladus), Mars, and Venus are for the most part, cold, methane-rich places where the potential for life has been visited over the years.

Anyway, these NASA researchers are going to Lake Untersee with the intent to search for extremophiles – tough microbes that thrive in conditions that are often considered to be too extreme for most other living things.

Richard Hoover, expedition leader of NASA’s Marshall Space Flight Center, notes that in recent years researchers have begun to realize that “Goldilocks zones” that contain what we consider to be perfect temperature and pH aren’t necessarily imperative for the existence of life. Researchers have found microbes in ice, boiling water, and even nuclear reactors – these extremophiles that were once considered to be oddities, may be the norm elsewhere in the cosmos. Of the expedition Hoover said:

With our research this year, we hope to identify some new limits for life in terms of temperature and pH levels. This will help us decide where to search for life on other planets and how to recognize alien life if we actually find it.”

What I found to be the most interesting discovery of Hoover’s expedition though, was the phenomenon of the “ice geyser” that the researchers discovered when they triggered one by drilling into a localized pocket of high pressure air in the upper layer of the ice sheet that covered Lake Untersee. This phenomenon may be pertinent to the recently discovered “ice geysers’ that erupt from the cracks in the “tiger strip” area of Enceladus. The ice bubbles that were found throughout the surface of Lake Untersee were also observed (by high-resolution dark field microscopy) to contain motile bacteria. The presence of viable bacteria frozen in the ice of this body of water suggests that maybe it isn’t completely necessary to drill through the thick icy crusts to search for life in the seas of the frozen moons of Jupiter and Saturn – viable cells may be cryptopreserved in the upper layers of the ice crust!

Thus, from this we learn that complex robots and machinery need not be capable of drilling down thousands of feet beneath the surface of these icy lakes and risk degradation by extreme conditions. They really only need to be able to drill down several hundred feet in order to encounter one of these ice bubbles in which life forms may have the potentially been preserved.

1 comment:

  1. So I was thinking about what you said about how better understanding what types of 'extremophiles' live on Earth will help us look for alin life because we will have a better idea of what forms they could take. Although, if we are using earthly life as a basis of this knowledge we will be looking for carbon and water-based life, and thus, how different could life actually look? Anyways this led me to think about something I just read in a paper by Lynn in which she describes the different extremophiles we know about and then says this will help us determine what types of earth life could live elsewhere then earth. The implication being that there is thought not just of the search for life but the transplantation of life on other planets. There are a lot of issues that go along with that but just thought I would mention that as it relates to research on extremophiles.