Hot spring systems occur worldwide, primarily in areas where volcanoes have been active. A hot spring is a place where warm or hot groundwater flows from the ground on a regular basis for at least part of the year. The water, which is significantly hotter than the surrounding surface temperature, is heated by geothermal heat (heat generated from the interior of the Earth). Hot springs may form various types of deposits at the surface, or there may be no significant surface deposits at all.
Most terrestrial and aquatic systems have pH values between 5 and 8, and are essentially neutral in pH (pH 7 is neutral; below 7 is acidic, above 7 is alkaline). However, the Nevada hot springs studied in this project are all quite alkaline, with pHs ranging as high as 10 (on a scale of 0-14) and water temperatures as hot as 60 degrees Centigrade (~140 degrees Fahrenheit).
The microorganisms (Crenarchaeota) found in these hot springs are considered unique because other members of this group that have been discovered to date have been found in acidic hot springs, not in hot alkaline environments. Organisms like these, that can live in such extreme (hot, alkaline) conditions, are called extremophiles.
Extremophiles are organisms that thrive under conditions that, from a human perspective, are clearly extreme. Extremophiles are known from very cold and very hot environments, and from salty, acid, and alkaline places where it was once assumed no organism could survive. Extremophiles not only survive in these places, they thrive.
The extremophiles studied in this project are members of the Domain Archaea, one of the three main groups of organisms that exist on Earth.
Find out more about Nevada hot springs...
- Geothermal resource maps--produced by the Idaho National Engineering and Environmental laboratory for the western U.S.
- Geothermal Resource Map of Nevada--produced by the Nevada Bureau of Mines.
- A History of Geothermal Energy in the U.S--provided by the U.S. Dept. of Energy Geothermal Technologies Program.
- Understanding hot springs and their formation--provided by MountainNature.com
- Thermal Waters of Nevada--Nevada Bureau of Mines and Geology Bulletin 91, by L.J. Garside and J.H. Schilling, 1979.
- Nevada Volcanoes and Volcanics--USGS website with some good links.
- Nevada hot springs--a list of the 312 Nevada hot springs with links to topo maps.
Find out more about other areas with hot springs...
- Lassen Volcanic National Park--in northeastern California, USA.
- Yellowstone National Park--in Idaho, Montana, and Wyoming, USA.
- Iceland--take a tour of the land of fire and ice.
Find out more about Extremophiles and the Archaea...
- Introduction to the Archaea--Life's extremists. Produced by the University of California, Berkeley. Information on life history and ecology, systematics, the fossil record, and morphology of the Archaea.
- The Archaea--sponsored by the American Society for Microbiology.
- Archaea and Bacteria--Rediscovering Biology on-line textbook.
- Life at High Temperatures--by Thomas D. Brock (1994), about the hot springs of Yellowstone National Park.
- How microbes survive extreme heat--sponsored by the American Society for Microbiology.
- Extremophiles--a website about extremophiles with lots of interesting links.
- Extremophiles--a website sponsored by ThinkQuest.
- The Mysterious Life of Caves--an article on extremophiles found in caves, by NOVA.
- Extreme Environments--sponsored by the Environmental Literacy Council; links to articles about a variety of extremophiles.
- Other Extreme Earth Life--lots of good information and links about extremophiles.
