Background

All living things must obtain energy from the environment to grow, to maintain a metabolic steady state, or simply to preserve viability.  The availability of energy sources in the environment thus represents a key factor in determining the size, distribution, and activity of biological populations, and ultimately constrains the possibility for life itself.  Energy, however, is everywhere.  To develop an incisive tool for understanding the interaction between microorganisms and their world requires that the biological demand for energy be understood and quantified.  A variety of constraints – theoretical, biochemical, culture-based, and environmental – can be brought to bear on this question, but these approaches have largely not converged to yield a single “answer”. 

Research at the frontiers of environmental microbiology – in particular, the discovery of microorganisms in several million year old sediments, or even in basement rock – has profoundly altered our perspective on the limits of living organisms and challenged our understanding of their need for energy.  Prokaryotic cells in the terrestrial or marine sub-surface may comprise 10% of all living biomass and most of the microorganisms on earth.  These organisms lie at the interface between the inhabited and uninhabited realms of our planet and represent the ultimate biological arbiters of chemical exchange between those spheres.  At several hundred meters below the sea floor, the energy flux and the theoretical growth rate of bacteria are orders of magnitude below anything we can understand from research on cultivated microorganisms. How is it possible to maintain complex functions in prokaryotic cells at an energy flux that barely allows cell growth over tens to thousands of years? Do these organisms have properties beyond our current understanding of microbial life, or are energy sources available that have not yet been identified?

Goals

To help address these questions, we are organizing a workshop to explore the biological demand for energy, with a specific focus on microorganisms.  The scientific goals of the workshop are to:

• Define the current state of knowledge about the basis for, and quantitative magnitude of, microbial energy requirements, with consideration of theoretical, culture-based, and environmental inputs;
• Identify gaps in our understanding of the biological demand for energy and how this demand may be satisfied by the environment, particularly in regards to life in the deep subsurface
• Identify priorities for research, technology development, and methods development that will most directly address these gaps in understanding

 An additional important aim of the workshop is to stimulate dialog, new thinking, and new, multi-faceted approaches to these questions by bringing together researchers from diverse but complementary disciplines, and engaging the interest of students and young scientists in this topic.

Format

The workshop will include approx. 70 international participants with expertise in a variety of relevant and complementary disciplines.  Examples include, but are not limited to:

• biochemistry (understanding the molecular basis of energy transduction)
• physical organic chemistry (understanding the thermodynamics of energy transduction)
• microbiology (culture-based approaches to quantify microbial energy requirements)
• environmental geochemistry and microbial ecology (characterization of energy fluxes and microbial populations in natural ecosystems) 

The workshop program will combine formal presentations with group discussion:

 Plenary Address:
On the opening evening of the workshop, a plenary lecture will be given by Professor Rudolf Thauer, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany, to mark the 30 year anniversary of publication of his influential review on microbial energetics (Thauer, R. K., K. Jungermann, and K. Decker, 1977, Energy conservation in chemotrophic anaerobic bacteria. Bacteriological Reviews 41: 100-180).

Invited Presentations:
Fifteen leading scientists representing diverse disciplines will present invited talks to frame and define the current state of knowledge in microbial bioenergetics and to provide a basis for subsequent group discussion. 

Contributed Oral and Poster Presentations:
The workshop format will allow for presentation of several contributed talks and an unlimited number of posters. Contribution of abstracts for oral or poster presentation is encouraged from all participants but is not a requirement of attendance. Submitted abstracts should specify a preference, if any, for oral or poster presentation.

Working groups:
A series of working groups will be organized and asked to develop and summarize findings and recommendations relative to the stated goals of the workshop, during two breakout sessions.  Working group themes will be developed at the time of the workshop, based on the relevant expertise of participants. 

Publication:
Program and abstracts will be printed and distributed to participants at the workshop.  A synopsis of key conclusions from the workshop may be submitted for publication in an international journal.  There is no manuscript requirement for published workshop proceedings.