Why Microbes?
Microbes drive the chemistry of life and affect the local climate. They make up 60% of the Earth's biomass, yet it is estimated that less than 1% of microbial species have been identified. By studying microbes, solutions to long-standing environmental and medical challenges may emerge. Scientists are also starting to appreciate the role played by microbes in global climate processes.
One of the earliest scientists to consider the role of microbes in the Earth's biosphere was Martinus Beijerinck who said of bacterial life, "Everything is everywhere and the media selects." When uttered these words, Charles Darwin was still formulating his ideas On the Origin of Species back in England and Mendel’s ideas were buried in obscurity, encased in a musty chest in the basement of his monastery in Austria. Beijerinck was interested in the diversity of life he studied on the microbial level. He was astonished at the success of these creatures and sought to understand their achievements. He hypothesized that they were Earth’s oldest children, patiently, and in some cases gleefully, tolerating the excesses of their upstart siblings. It is his work (and the insightful ideas of his Russian colleague Sergie Winogradsky) we are replicating and extending to the larger theme of genomics.
The following experiments were selected to meet many goals. First among them is to demonstrate the enormous diversity of bacteria in their natural environment. These experiments drive home the idea of interconnections and interdependency. Construct a Winogradsky column, watch it long enough and you will see empires rise and flourish. Before too long, the hegemony of one will be replaced by the eager desire of another. A violent struggle will ensue between unlimited growth and limited resources. You will see that homeostasis is not a pretty sight, and equilibrium tenuous at best. Finally, the power of genomic tools will reveal the cast of characters and allow you to document the progress of these microbial communities.
Many biology and life science classes have at least a single unit on biological classification. Most classroom attempts at classification result in systems that are artificial, that is, based upon features that students can easily observe. Many of these phenotypic features are fairly far-removed from the actual genes that code for them. Scientists who study classification and evolutionary relationships strive to develop classification systems that are natural, that is, based upon information coded for by the genetic material. DNA sequence data have permitted scientists to perform genomic comparisons among organisms and this information is changing some long-held views of the history of life. This tree of life-or phylogenetic tree-traces the pattern of descent of all life over millions of years into three major branches, Bacteria, Archaea and Eukarya. These branches were largely determined based upon evidence from genomic sequencing.
Lastly another goal of these experiments could be to model principles relevant to global climate change. Through a simple chemical titration, it is possible to determine how much carbon dioxide these bacteria produce. They are enormously successful in this process. Equally impressive are the photoautotrophic and chemoautotrophic bacteria that act as a sink for carbon dioxide. As we become reasonably certain of the correlation between carbon dioxide emissions and the corresponding alteration to climatic patterns (i.e. warming), these diminutive bacteria offer important insights into the global systems of our planet. Although correlation does not equate causation, the preponderance of evidence suggesting that human activity is altering the planet begs our attention. The contrarian ostrich may continue to bury his head in the sand, but prudence dictates that we seriously evaluate how we go about the routines of life. Regardless of our fate, the Winogradsky column informs us of one stark fact. Life will continue on this planet and bacteria will be around, with or without us.