Extremophiles

Written by Dr. T. M. Wassenaar Tuesday, 06 January 2009

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As discussed in the exhibit on Evolution, bacteria have the potential to adapt to extreme conditions. Many places on Earth are too harsh to support most life forms, but can support bacteria. Before we explore some of the hottest, coldest, darkest and deepest places of our planet, let's have a look at some bacteria with extraordinary characteristics.
  • Larger than life bacteria were isolated from a kind of surgeon fish. Large bacteria were also found off the coast of Namibia. The Thiomargarita namibiensis can be seen with the naked eye!.
  • Did you know that bacteria can have babies too ? These are an exception, for most bacteria divide by fission budding. This means that as the cell grows, the body mass increases until their body divides into two equal parts, each receiving its equal share of constituents, including the (then completely duplicated) DNA. However, sexual reproduction is also possible, as is explained in the exhibit on Evolution.
  • Some bacteria can 'feel' a magnetic field, and they don't even need a compass to know where North is. The following link contains a lot of jargon, but is still interesting: Bacteria can 'feel' a magnetic field .
  • Would you believe that bacteria can make gold? (Source: K. S. Kruszelnicki). Don't get the impression that microbiologists are the alchemists of the twentiest century, but it is tempting to investigate this matter further. There may be a 'golden' future for the person who can cultivate these jewels! 
Impressive as these weird organisms are, let's have a look at archaebacteria that are counted among the Extremophiles: those who live under extreme conditions. Check our exhibit on the origin of life what archaebacteria are.
Deep down underground, within the Earth's crust, bacteria can be found as the only living creatures. . More about deep subsurface bacteria (American Geophys. Union). High concentrations of salt normally kills bacteria as our forefathers knew who salted their meat and vegetables to keep them from spoiling. However, some bacteria survive in high salt conditions; they are called halophiles. Do you like a hot bath? Bacteria will beat you. Some bacteria live at extremely high temperatures near to the point of boiling water: Read all about life at high temperatures. Or do you prefer the cold zones? Bacteria have been found under arctic ice. Less spectacular for science-fiction than ET, but breath-taking if it were true; judge for yourself: are bacteria present in a meteorite? The jury is still out, as the observed structures could also have a geochemical background. Maybe bacteria will give the answer to this question we all would like to know: Is life on mars possible?. At least there are bacteria that grow in simulated Mars. And here's how they investigate whether life is/was present on Mars. Bacteria in space: some bacteria went to the moon and came back--alive!.

Extremophiles have played their best part in the early development of our biosphere, when conditions were much different from present. Bacteria that used iron for food are still very much alive. Such weird bacteria were essential to form the atmosphere that enabled the development of other (should we really call them higher?) life forms. Knowing how diverse bacteria can be, you can only wonder about these increadible little creatures.

Last Updated on Sunday, 01 March 2009