Do Species Matter in Microbial Communities?
Do microbes--the little guys of the planet--belong to one big gene pool or to numerous smaller, discrete ones? Scientists are trying to settle the question using microbes in Yellowstone Nationawl Park
"The big question is whether genetic exchange is fast or not fast" in microbial populations, explained Dave Ward, a professor of microbial ecology and TBI scientist at Montana State University-Bozeman. Ward has studied Yellowstone microbes for more than 25 years, and is a leader in the thermal biology field.
Now Ward is spearheading the five-year project that will take a closer look at the colorful bacteria mats that grow in Yellowstone hot springs.
One popular idea is that microbes rampantly and somewhat promiscuously swap bits of
their genomes, or life codes.
If microbes readily disperse across the globe, this would make them quite unlike plants and animals, which are known to form distinctly adapted and geographically distributed species.
But scientists like Ward have shown that microbes in unique environments, such as Yellowstone's, represent specific populations that have evolved to survive in distinct ecological habitats and places around the world. “That view of diversity is no different from the one governing larger species”, Ward said, adding that “evolutionary pressure should affect microbes the same way it affects elk”. But others disagree, and the issue recently hit the pages of the journal Science (Vol.15 , August 2003) and the New York Times (August 26th, 2003) when the results of two new studies supported the idea of distinct microbial populations in different hot springs around the world. Ward was involved in one of the studies.
The National Science Foundation is addressing this diversity debate through a new program called Frontiers in Integrative Biological Research. Designed to answer the big questions in biology, this program just made its first six awards out of more than 114 proposals from scientists around the country. In addition to Montana State University TBI scientist Dr. Dave Ward and Yellowstone Park, the project involves scientists from Wesleyan University, Stanford University/Carnegie Institution of Washington, the Institute for Genomic Research, the University of Copenhagen, the aerospace company Lockheed-Martin and the NASA Astrobiology Institute. The title of the grant is “Do species matter in microbial communities?”
“Resolving this question is one of the greatest challenges in all of science, made possible by a new era of environmental metagenomics methods," said Matt Kane, director of NSF's Microbial Observatories Program. And where better to conduct this study than Yellowstone? The variety of environmental gradients and habitats probably harbor more microbial diversity than any other single site on our pla- net."
Ward describes his project as high-risk, because of the new technologies his group will use, but one with high poten tial impact. The results could get microbiologists past a crossroads of sorts. It would help them better predict the behavior of microbial communities and how the communities would change if the environment changes.
That predictive ability matters for such applications as bioremediation, where microbes can be harnessed to clean up polluted soil or water. If scientists don't understand diversity well enough, they can’t know which microbes will do the job under different environmental conditions.
For Yellowstone and its visitors, Ward's studies offer a greater opportunity to appreciate the role of the unseen in creating the unique beauty of the park. Microbes are part of the interwoven fabric that comprises Yellowstone’s fantastic reserve of biodiversity.