Geysers, Volcanoes, and Hot Springs

These geologic features, which arise from geothermal activity, are not just hot; they’re heavily permeated by sulfurous compounds. These environments may resemble Venus or the early Earth. Microbes living in geysers, volcanoes, and hot springs have managed to adapt and even make use of chemicals that would be toxic to most life on Earth today.

"Life at High Temperatures"
(From the University of Wisconsin):
http://www.bact.wisc.edu/Bact303/b1

"Bugs from the Deep May Be Window into the Origins of Life–on Earth and Beyond"
(From the American Association for the Advancement of Science) :
http://www.aaas.org/news/releases/2003/0214bugs.shtml

"Brave New Biosphere"
(From the Why Files):
http://whyfiles.org/022critters/hot_bact.html

"Extremities: Geology and Life in Yellowstone and the Implications for Other Worlds"
(From the Lunar and Planetary Institute):
http://www.lpi.usra.edu/education/EPO/yellowstone2002/

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High Altitude and Polar Lakes

Lakes in Earth's extreme environments might be similar to frozen bodies of water on Mars or elsewhere. Because ultraviolet (UV) exposure increases with altitude, the microorganisms found in these lakes can provide clues to how life survived on a long-ago Earth without oxygen in its environment. That, in turn, can help us understand how life could arise and adapt on other planets.

"What's Living in the World’s Highest Lake?"
(From Astrobiology Magazine ):
http://www.astrobio.net/news/article297.html

Explore the Highest Lake on Earth
(Site describing a scientific expedition to Licancabur in October 2002):
http://www.extremeenvironment.com

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Deep-Sea Vents and Salt Ponds

Both of these Earthly features are seemingly inhospitable to life, and yet are host to a surprising number of organisms. In 1977, scientists discovered rich ecosystems in deep-sea vents, sites of underwater volcanic activity that involve smoldering temperatures and usually-toxic chemicals. Salt ponds teem with bacteria that have adapted to concentrations many times greater than those found in the open ocean.

Deep Ocean Exploration Institute
at Wood's Hole Oceanographic Institution:
http://www.whoi.edu/institutes/doei/currenttopics/ct_hydrothermal.htm

" Salt of the Early Earth"
(From Astrobiology Magazine) :
http://zdna2.umbi.umd.edu/~dassarma/Astrobiology.html

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Deserts

Water is essential for life as we know it. By studying organisms that survive in Earth's driest climates, we can learn more about the hydration limits of life and how some species have evolved ways to find and use water. For example, in Antarctica's Dry Valleys, microorganisms burrow into porous rocks where water collects. The environment of Mars resembles these dry, cold deserts on Earth.

Antarctica's Dry Valleys
"How to Melt a Glacier":
http://www.exploratorium.edu/origins/antarctica/fieldnotes/dvalleys.html

"The Driest Place on Earth"
(An article about Chile's Atacama desert from NASA's Astrobiology Institute):
http://www.nai.arc.nasa.gov/news_stories/news_detail.cfm?ID=17

"The Search for Extreme Life"
(From Scientific American) :
http://www.sciam.com/article.cfm?articleID=00072444-3A0B-1C74-9B81809EC588EF21&pageNumber=1&catID=2

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Solar System and Beyond

Mars, Jupiter's moon Europa, and possibly some newly discovered planets outside our solar system may have conditions that support life. While scientists have a good idea of what constitutes a habitable environment, they are still trying to learn how many planets or other celestial bodies harbor such conditions. As researchers explore Earth's extreme environments for life's adaptations, they continue to examine how life may have started or thrived elsewhere.

NASA's Mars Exploration Program:
http://mars.jpl.nasa.gov/

Life on Europa
(From the Wayne Country Regional Education Service Agency):
http://www.resa.net/nasa/europa_life.htm

The nature and distribution of habitable environments in the universe
(From the Astrobiology Roadmap):
http://astrobiology.arc.nasa.gov/roadmap/g1.html

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Toxic Mines and Nuclear Reactors

These two human-made environments are among those considered the harshest on Earth. To the astonishment of many biologists, some families of microbes have adapted to even these unfriendly conditions. Such findings demonstrate that even the most extreme and deadly environments for humans are capable of supporting life.

The evolutionary mechanisms and environmental limits of life
(From the Astrobiology Roadmap):
http://astrobiology.arc.nasa.gov/roadmap/g5.html

"Meet the Super Bug: Radiation-Resistant Bacteria May Clean Up Waste Sites"
(From the Environmental News Network) :
http://www.enn.com/features/1999/04/040999/superbug_2581.asp

"Bacteria in Hot Acid Springs"
(From the University of Wisconsin) :
http://www.bact.wisc.edu/Bact303/b13

"Algae in Acid Hot Springs"
(From the University of Wisconsin) :
http://www.bact.wisc.edu/Bact303/b21

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