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Theme:
Bioenergetics
a) Bioenergetics
b) 5-year RCN synthesis
Date: 2014
Host: To be determined
Organizers: To be determined
Scientific Conference: All life requires
energy – the diverse redox couples that supply the energy
for metabolism and the amounts of energy yielded will be the
central topics of the meeting. Thermodynamic data as a function
of temperature and pressure are now available for thousands
of redox-sensitive minerals, gases, liquids, and aqueous species,
including many organic compounds. Gibbs energies of known
and potential net catabolic reactions have been calculated
in a variety of oxic and anoxic systems (Amend et al. 2003;
Bach and Edwards 2003; Shock et al. 2005; Spear et al. 2005;
Rogers and Amend 2006), but the energetics of the deep subsurface
biosphere remain largely unexplored. In addition, energy requirements
for anabolic (i.e., biomass synthesis) processes
under geologically relevant conditions have received only
limited attention (McCollom and Amend 2005; Amend and McCollom
2008). The science sessions will distill major developments
in theoretical biogeochemistry and present these in the context
of lab and field experiments that inform about minimum energy
requirements for microbial communities and rates of redox
reactions. A particular focus will be on ecosystems where
temperature, pressure, and chemical energy availability are
near or at life's limits.
Education Workshop: The energetics workshop
portion of the meeting will feature hands-on tutorials with
fundamental thermodynamic and kinetic computer codes. Central
to this effort is the ability to accurately compute standard
state properties of individual species and chemical reactions
at elevated temperatures and pressures. These properties then
can be used in solubility, speciation, and reaction path modeling
to evaluate thermodynamic stability and overall Gibbs energies
of reaction (ΔGr) as a function of temperature, pressure,
and chemical composition, incorporating activity and fugacity
coefficients in the process. The modeling is amenable to dissolution,
precipitation, redox, and acid-base reactions in single- or
multi-phase systems that can include complex organic compounds
and biomolecules.
RCN Synthesis: The final session
of the meeting will synthesize and evaluate the RCN activities
of the 5-year grant period. A final report will be generated
that, on the one hand, highlights the accomplishments of the
meetings, student exchanges, and research coordination efforts,
and, on the other, proposes ways to build on successes and
learn from mistakes for future deep biosphere research. Although
NSF (and other agency) program managers are welcome at all
the RCN meetings, their involvement at this synthesis meeting
is most critical. The "epilogue" of this RCN will
serve as the "prologue" for the next generation
of coordinated deep biosphere investigations.
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