PSU Magazine Spring 2000

In the bubbling springs of Yellowstone, in steaming water too hot to touch, lives a universe of life more diverse than all the plants and creatures of the Amazon rain forest. Two miles under the ocean, in a world of unbearable pressure only slightly warmer than ice, lives another multitude producing an energy source that rivals all the Earth's known petro– leum reserves. These are microscopic bacteria, and they come closer than any other life form on the planet to what scientists call the "universal ancestor"-the oldest form of life. Billions of years before humans or dinosaurs or even trees, these bacteria were populating the planet. And they'll be here long after we're gone. Three PSU scientists are studying these microbes in extreme hot and extreme cold parts of the world. In the process, they are finding the telltale signs of life's beginnings, and with enough information, they may help to determine if life ever existed on other planets. The three faculty members, all relatively new to PSU, are: David Boone, a professor of environ– mental microbiology, who studies methane-producing bacteria---called methanogens-from cold environ– ments. He has the largest collection in the nation of these types of bacteria. Sherry Cady, assistant professor of geology, whose work takes her to hot springs in Oregon, Wyoming, and New Zealand. While Boone and Anna– Louise Reysenbach study microbes themselves, Cady is primarily inter– ested in the fossil biosignatures they leave behind. She has proposed that PSU establish a Center for Life at Extreme Environments to blend a number of disciplines in this type of research. Anna-Louise Reysenbach, a microbial biologist, who came to PSU from Rutgers University in January 1999. She is one of the principal investiga– tors in a National Science Foundation (NSF) grant to study life in and around deep-sea sulfide chimneys, and also does extensive research in the hot springs of Yellowstone National Park. why study microbes? •••• For one reason, there are so many of them and so few of them have been studied and given names. "Ten billion microbes can live in the amount of soil you can pinch between your thumb and forefinger, representing thousands of species, almost none of which is known to science," says Reysenbach, quoting from author and scientist E.O. Wilson. For another reason, microbes play an absolutely essential part in all life. They are the chemists of the world, the recyclers. They are responsible for photosynthesis, the making of natural gas, and the breaking down of organic matter into soil. If we didn't have microbes, we wouldn't have bread, beer, or yogurt. Microbes give them the rise, the alco– hol, the tang that make them what they are. They are also great at cleaning up man-made disasters. The extent to which the 1989 oil spill off Valdez, Alaska, is cleaned up has at least as much to do with oil-eating microbes as it does with any effort by human beings. There may even be microbes that can help detoxify nuclear radiation. "We try to help the microbes as much as we can, but they're mostly doing it themselves," says Reysenbach. PHOTO BY SHERRY CADY "If you disrupt an environment, the life that bounces back the quickest and in the biggest way are the microbes." Bacteria are so important to all life on earth that it brings up another question-and another reason to study them: Are we humans doing anything to disrupt the microbial world? If so, we may be signing our own death warrant. If we are doing anything to tip the balance-by causing some forms of bacteria to become extinct, or to encourage one type to thrive at the expense of another-we could, for example, trigger a change in the atmosphere that years from now could extinguish life. All life, of course, except the microbes. So if bacteria are everywhere, why are these scientists going to the most extreme environments on Earth to study them? One reason, according to Cady, is that these places exclude almost all other forms of life. They are places of near-boiling water, of high acidity or its opposite, high alkalinity. Not many things can live there-except for certain types of microbes. By going to these places, researchers have a clear Could life have begun in a hot world? Primitive organisms found in Yellowstone's thermal pools lend support to the theory. SPRING 2000 PSU MAGAZINE 7