The Microbial Engines That Drive Earth's Biogeochemical Cycles
Paul G. Falkowski,1*
Tom Fenchel,2*
Edward F. Delong3*
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.
1 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.
2 Marine Biological Laboratory, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark.
3 Department of Civil and Environmental Engineering and Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
* To whom correspondence should be addressed. E-mail: falko{at}marine.rutgers.edu (P.G.F); tfenchel{at}bio.ku.dk (T.F.); delong{at}mit.edu (E.F.D.)
