Tracking microbial biodiversity through molecular and genomic ecology.

Molecular ecology and metagenomics applied to the study of microbial biodiversity are changing our comprehension of the biosphere. An impressive diversity of archaea, bacteria and, more recently, protists has been uncovered by molecular tools. Efforts to couple function to the phylogenetic diversity observed in natural environments are leading to the discovery of novel metabolisms and to a re-evaluation of the global ecological impact of known ones. Interesting questions relating to mechanisms of speciation and evolutionary trends at the smallest and largest phylogenetic scales are emerging.