Journal
ECOLOGY
Volume 91, Issue 9, Pages 2604-2612Publisher
ECOLOGICAL SOC AMER
DOI: 10.1890/09-1365.1
Keywords
bacteria; carbon cycling; iron reduction; Luquillo Mountains; methanogenisis; microbial ecology; Puerto Rico; tropical forest soils
Categories
Funding
- National Science Foundation (NSF) [DEB-0543558, DEB-0218039]
- NASA [NGT5-30463]
- Mellon Foundation
- USDA- IITF
Ask authors/readers for more resources
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 communities central to the belowground carbon cycle in these wet tropical forests. The exceedingly high abundance of iron-reducing bacteria (up to 1.2 x 10(9) cells per gram soil) indicated that they possess extensive metabolic capacity to catalyze the reduction of iron minerals. In soils from the higher rainfall sites, measured rates of ferric iron reduction could account for up to 44% of organic carbon oxidation. Iron reducers appeared to compete with methanogens when labile carbon availability was limited. We found large numbers of bacteria that oxidize reduced iron at sites with high rates of iron reduction and large numbers of iron reducers. The coexistence of large populations of iron-reducing and iron-oxidizing bacteria is evidence for rapid iron cycling between its reduced and oxidized states and suggests that mutualistic interactions among these bacteria ultimately fuel organic carbon oxidation and inhibit CH(4) production in these upland tropical forests.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available