Biocomplexity is the term that is becoming used to describe efforts 
to understand strongly-interacting dynamical systems with a biological, 
ecological or even social component.  I provide a brief overview of why 
this field is not only interesting for physicists, but can benefit 
substantially from their participation.  As a case study, I present my 
own work on geobiological pattern formation.

Microbes are the "dark matter" of biology. Constituting well over half 
the Earth's biomass, they form the foundation for all known ecosystems,
yet only about 1% of them have been characterized and their global 
effects understood. Modern microbiology "the forgotten frontier" 
represents a fascinating opportunity for physicists to contribute to 
biology, because microbes are simple forms of life, but not too simple. 
Moreover, the techniques of statistical mechanics are ideally suited to 
exploring problems with biocomplexity, such as the ecology of microbial
communities and the evolutionary dynamics of microbial genomes. I'll 
describe my group's recent field, experimental and theoretical work on 
two topics: (1) the possible role of microbes in creating scale-invariant 
travertine terraces at geothermal hot springs , and (2) microbial genome 
evolution how there can be global genome diversification in the absence 
of species.

The ability to distinguish both ancient and modern geological features that 
are biologically influenced from those that are purely abiotic in origin can
potentially advance our understanding of the timing and pattern of 
evolution, and may even provide a tool with which to identify evidence 
for life on other planets.

Work performed in collaboration with: G. Bonheyo, J. Frias-Lopez, 
H. Garcia-Martin, J. Veysey, B. Fouke.

Work supported by the US National Science Foundation.