All living organisms 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 it ultimately constrains the possibility of life itself.

The biological demand for energy

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 approaches – theoretical, biochemical, organic geochemical, culture-based, and environmental – can be brought to bear on this question, but results have not converged to yield a single “answer”.

Extremely low energy fluxes

Prokaryotic cells in the terrestrial or marine sub-surface may comprise most of the microorganisms on earth, but they have access to less than 1%  of the energy fixed by photosynthesis annually. These organisms live 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. The Center strives to understand how prokaryotic cells maintain complex functions 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?

KEY PUBLICATIONS FROM CfG

• Lomstein, Bente Aagaard; Langerhuus, Alice Thoft; D'Hondt, Steven; Jørgensen, Bo Barker; Spivack, Arthur J. /Endospore abundance, microbial growth and necromass turnover in deep sub-seafloor sediment. Nature, Vol. 484, 18.03.2012, s. 101-104.

• Lomstein, Bente Aagaard; Langerhuus, Alice Thoft; D'Hondt, Steven; Jørgensen, Bo Barker; Spivack, Arthur J./ Endospore abundance, microbial growth and necromass turnover in deep sub-seafloor sediment. Nature, Vol. 484, 18.03.2012, s. 101-104. Supplementary information
• Røy, H., Kallmeyer, J., Adhikari, R. R., Pockalny, R., Jørgensen, B. B. & D'Hondt / Aerobic Microbial Respiration in 86-Million-Year-Old Deep-Sea Red Clay. Science, vol. 336, s. 922-925, 2012.
• Jørgensen, Bo Barker. / Deep subseafloor microbial cells on physiological standby. PNAS, Vol. 108, no. 45, 18193-18194, 2011.
• Orcutt, Beth N. ; Sylvan, Jason B. ; Knab, Nina J. ; Edwards, Katrina J. / Microbial Ecology of the Dark Ocean above, at, and below the Seafloor. In: Microbiology and Molecular Biology Reviews, June 2011, Vol. 75, No. 2, p. 361-422.
• Tarpgaard, I. H., H. Røy, B. B. Jørgensen (2011) "Concurrent low- and high-affinity sulfate reduction kinetics in marine sediment", Geochimica et Cosmochimica Acta, 75: 2997-3010.
• Lever, Mark. / Acetogenesis in the energy-starved deep biosphere - a paradox?. Frontiers in Microbiology, no. 2, 1-18, 2012.
• Jørgensen, B. B. and S. D'Hondt (2006) "A starving majority deep beneath the seafloor". Science, 314: 932-934.