Exploring Earth's intraterrestrial ecosystems is a relatively new and exciting field with ever expanding frontiers made possible by advances in technology and instrumentation. In May 2012, a review article by Edwards et al.  highlighted the recent history of this research field and the intriguing new directions this science is heading. The article discusses some of the most active and interesting realms being scrutinized by researchers delving the deep, dark energy biosphere.
During the last 1.5 years, instrumentation and research support by the Deep Carbon Observatory has contributed to and enhanced the exploration of the deep biosphere, as mentioned in the article. Specifically, the DCO helped launch the Census of Deep Life (CoDL), which is in its initial phase of a global survey of deep life in continental and marine environments. The DCO also helped support development of the prototype Dark Energy Biosphere Investigative tool (DEBI-t), which was used on the Integrated Ocean Drilling Program's Mid-Atlantic Microbiology Expedition in Fall 2011.
More recently, in December 2011, the Alfred P. Sloan Foundation approved funding for the DCO's Deep Life (DL) Community proposal entitled "Deep Life I: Microbial Carbon Transformations in Rock-Hosted Deep Subsurface Habitats." The proposal's overarching goal is to constrain the pathways and controlling factors for microbially-mediated carbon cycling in subsurface ecosystems fueled by water-rock reactions that generate H2 and hydrocarbons. The work leveraged by this proposal is part of the exciting future Edwards et al. (2012) discuss.
Figure: Locations of existing scientific drilling program basement legacy holes