title: Life under extreme energy limitation: a synthesis of laboratory- and field-based investigations.
abstract: The ability of microorganisms to withstand long periods with extremely low energy input has gained increasing scientific attention in recent years. Starvation experiments in the laboratory have shown that a phylogenetically wide range of microorganisms evolve fitness-enhancing genetic traits within weeks of incubation under low-energy stress. Studies on natural environments that are cut off from new energy supplies over geologic time scales, such as deeply buried sediments, suggest that similar adaptations might mediate survival under energy limitation in the environment. Yet, the extent to which laboratory-based evidence of starvation survival in pure or mixed cultures can be extrapolated to sustained microbial ecosystems in nature remains unclear. In this review, we discuss past investigations on microbial energy requirements and adaptations to energy limitation, identify gaps in our current knowledge, and outline possible future foci of research on life under extreme energy limitation.
authors.affiliation: Center for Geomicrobiology, Institute of Bioscience, Aarhus University, Ny Munkegade 114, 8000 Aarhus C, Denmark mark.lever@usys.ethz.ch.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Lever
authors.affiliation: Rensselaer Polytechnic Institute, Earth and Environmental Sciences, Jonsson-Rowland Science Center, 1W19, 110 8th Street, Troy, NY 12180, USA.
authors.forename: Karyn L
authors.initials: KL
authors.lastname: Rogers
authors.affiliation: Department of Microbiology, University of Tennessee at Knoxville, M409 Walters Life Sciences, Knoxville, TN 37996-0845, USA.
authors.forename: Karen G
authors.initials: KG
authors.lastname: Lloyd
authors.affiliation: Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Inhoffenstraße 7B, D-38124 Braunschweig, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Overmann
authors.affiliation: Microbial Ecology, Department of Biology, University of Konstanz, P.O. Box 55 60, D-78457 Konstanz, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schink
authors.affiliation: Max Planck Institut für terrestrische Mikrobiologie, Karl-von-Frisch-Straße, D-35043 Marburg, Germany.
authors.forename: Rudolf K
authors.initials: RK
authors.lastname: Thauer
authors.affiliation: NASA Ames Research Center, Mail Stop 239-4, Moffett Field, CA 94035-1000, USA.
authors.forename: Tori M
authors.initials: TM
authors.lastname: Hoehler
authors.affiliation: Center for Geomicrobiology, Institute of Bioscience, Aarhus University, Ny Munkegade 114, 8000 Aarhus C, Denmark.
authors.forename: Bo Barker
authors.initials: BB
authors.lastname: Jørgensen
mesh_terms: D000222:Adaptation, Physiological; D018407:Bacterial Physiological Phenomena; D017753:Ecosystem; D004734:Energy Metabolism; D012106:Research / Q000592:standards
keywords: adaptation; energy limitation; laboratory; microbial life; starvation; subseafloor