From Geocycles to Genomes and Back

INTRODUCTION A holy grail for environmental microbiologists is being able to predict the effects of any given microbial community on a particular environment. In an era of increasingly dramatic changes in global climate, this goal is becoming evermore important. It is now well accepted that microorganisms have had and continue to have a profound influence on shaping the chemistry of the Earth. It would thus be both intellectually satisfying and practically useful if we could enumerate the microbial players in a specific locale, and, knowing their metabolic potential and how they regulate their various metabolisms, make predictions about how their presence would shape the geochemistry of that locale as it evolves in time. Despite significant progress that has been made in developing tools that would aid in this effort in the past decade, we are still very far from being able to accomplish this. This is due to many factors, including our limited