title: The microbial engines that drive Earth's biogeochemical cycles.
abstract: Virtually all nonequilibrium electron transfers on Earth are driven by a set of nanobiological machines composed largely of multimeric protein complexes associated with a small number of prosthetic groups. These machines evolved exclusively in microbes early in our planet's history yet, despite their antiquity, are highly conserved. Hence, although there is enormous genetic diversity in nature, there remains a relatively stable set of core genes coding for the major redox reactions essential for life and biogeochemical cycles. These genes created and coevolved with biogeochemical cycles and were passed from microbe to microbe primarily by horizontal gene transfer. A major challenge in the coming decades is to understand how these machines evolved, how they work, and the processes that control their activity on both molecular and planetary scales.
authors.affiliation: Environmental Biophysics and Molecular Ecology Program, Institute of Marine and Coastal Sciences and Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ 08901, USA. falko@marine.rutgers.edu
authors.forename: Paul G
authors.initials: PG
authors.lastname: Falkowski
authors.forename: Tom
authors.initials: T
authors.lastname: Fenchel
authors.forename: Edward F
authors.initials: EF
authors.lastname: Delong
mesh_terms: D001105:Archaea / Q000235:genetics / Q000378:metabolism*; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001272:Atmosphere; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005075:Biological Evolution; D018534:Earth, Planet; D017753:Ecosystem; D004602:Elements; D022761:Gene Transfer, Horizontal; D019766:Genes, Archaeal; D005798:Genes, Bacterial; D014644:Genetic Variation; D055593:Geological Phenomena; D005844:Geology; D053858:Metabolic Networks and Pathways; D010084:Oxidation-Reduction; D010788:Photosynthesis; D013816:Thermodynamics
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D004602:Elements