Falkowski, P., T. Fenchel, and E. Delong. 2008. The microbial engines that drive the earths biogeochemical cycles. Science. 302, 5879:1034-1039.
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.
I chose this article because of the great explanations of microbial involvement in biogeochemical cycling on a chemical basis, touches on the evolution of these processes, and explains how they control activity on different levels.