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.