Whether microbes--the little guys of the planet--belong to one big gene pool or to numerous smaller, discrete ones doesn't sound like the stuff of controversy.
But among the microbiologists of the world, the issue is big enough that the National Science Foundation has put up $5-million to try to settle the question using microbes in Yellowstone National Park.
"The big question is whether genetic exchange is fast or not fast" in microbial populations, explained Dave Ward, a professor of microbial ecology at Montana State University-Bozeman. Ward has studied Yellowstone microbes for more than 25 years.
Now he is spearheading the five-year project that will take a closer look at the colorful bacteria that grow in communities called mats in Yellowstone hot springs.
"[Ward's] developing a foundation for our understanding of the diversity of this life," said Diane Chalfont, the park's chief of interpretation. Chalfont will incorporate elements of the new study into educational displays for the public at the Old Faithful Visitor Education Center and other sites in the park.
For years, the dogma has been that microbes rampantly and somewhat promiscuously swap bits of their genomes, or life codes, which would mean they exist worldwide as one big melting pot of genes. If so, that would mean any microbe could live just about anywhere.
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 habitats and places around the world using a specialized set of genes.
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 and the New York Times when the results of two new studies supported the idea of distinct microbial species. Ward was involved in one of the studies.
Now the National Science Foundation is addressing the debate through a new program called Frontiers in Integrative Biological Research. Designed to answer the big questions in biology, the program just made its first six awards out of more than 114 proposals from scientists around the country.
"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 harbors more microbial diversity than any other single site on our planet."
In addition to how microbes evolve, the other big questions funded by the frontiers program include how, cell by cell, a plant develops leaves, flowers and other structures and how ecology and molecular genetics interact to create new species.
Ward described his project as high-risk because of the new technologies his group will use but one with high potential 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. But not if scientists don't understand diversity well enough to know which microbes will do the job under different environmental conditions.
For Yellowstone and its visitors, Ward's studies create a greater opportunity to appreciate the role of the unseen in creating the unique beauty of the park.
"At first blush, visitors are impressed by the mammals and diversity on a large scale," said the park's Chalfont. But once they ask about the reason for the hot spring colors they learn that microbes make the green, orange and other hues.
"Microbes are part of the huge fabric that makes up Yellowstone National Park," said Chalfont.
In addition to MSU 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.
More information about the program can be found at http://landresources.montana.edu/FIBR/
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