Life in Extreme Environments
Lynn Rothschild is a researcher in Synthetic Biology at NASA Ames and has offered her lecture on extremophiles each year in the course. You can also watch her lecture in 2010 and 2009 on Stanford Youtube, and as far back as 2008 on iTunes.
Normal is passe; extreme is chic. While Aristotle cautioned “everything in moderation”, the Romans, known for their excesses, coined the word “extremus”, the superlative of exter, being on the outside. Perhaps even more marvelous is the detection of organisms that thrive in extreme environments. The late Bob Macelroy of NASA Ames named these lovers (“philos” to the Greeks) of extreme environments “extremophiles”.
The discovery of extreme environments and the organisms that inhabit them have infused the search for life outside the Earth, and even the possibility of panspermia, with plausibility. Extremophiles provide a minimum environmental envelope in which life can exist. And, happily, the discovery of extremophiles has put vitality into the biotech industry and dreams of stock options in the minds of field biologists. The field has exploded during the last decade, with several reviews available on extremophiles, an increasing number of meetings, genomes sequenced and mined, patents filed, and concerted funding programs initiated.
Here we examine what it means to be an extremophile starting from first principles. We argue that in the context of life, “extreme” means an environment that makes it extremely difficult to keep a living entity intact and functional. We argue that all life would be based on organic carbon, so any environment that destroys organic carbon, for example, is a non-starter. Ditto with the solvent for earth-based life, water. If water isn’t liquid, there is no life….maybe. We highlight extremophiles that are often overlooked, possibly because they are eukaryotes. We then focus on the significance of extremophile research to the search for life in the universe, and conclude with a discussion of the future of extremophile research including their economic potential.