We report that iron‐reducing bacteria are primary mediators of anaerobic carbon oxidation in upland tropical soils spanning a rainfall gradient (3500–5000 mm/yr) in northeast Puerto Rico. The abundant rainfall and high net primary productivity of these tropical forests provide optimal soil habitat for iron‐reducing and iron‐oxidizing bacteria. Spatially and temporally dynamic redox conditions make iron‐transforming microbial c...

Tropical forests are an important source of atmospheric methane (CH 4 ), and recent work suggests that CH 4 fluxes from humid tropical environments are driven by variations in CH 4 production, rather than by bacterial CH 4 oxidation. Competition for acetate between methanogenic archaea and Fe(III)‐reducing bacteria is one of the principal controls on CH 4 flux in many Fe‐rich anoxic environments. Upland humid tropical forests...