Duration of O2 Exposure Determines Dominance of FeII vs CH4 Production in Tropical Forest Soils
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Temporal fluctuations in redox conditions influence the availability of Fe III and greenhouse gas emissions in humid upland soils. However, the impact of fluctuation duration on biogeochemical processes remains unclear. We hypothesized that rates of Fe III reduction and CH 4 production are sensitive to the duration of soil oxygenation. To test this, surface soil from the Luquillo Forest, Puerto Rico, was subjected to fluctuating redox conditions with an anoxic interval of 6 days followed by oxic intervals of either 8, 24, or 72 h. Shorter oxic intervals enhanced Fe reduction, while longer oxic intervals enhanced CH 4 emissions. As O 2 exposure decreased from 72 to 8 h, Fe reduction rates increased from 0.12 ± 0.02 to 0.26 ± 0.05 mmol kg –1 h –1, whereas cumulative CH 4 decreased from 44.0 ± 4.7 to 12.7 ± 4.6 μmol kg –1 . 13 C-amino acid spikes were preferentially incorporated into the DNA of iron reducers ( Anaeromyxobacter sp.) in the shorter oxic treatment (8 h vs 24 h), suggesting that Fe reducers are less inhibited by shorter periods of oxidation. Conversely, longer oxygen pulses appear to suppress Fe reducers more than methanogens, leading to increased CH 4 emissions. These findings highlight the role of the redox oscillation length in modulating biogeochemical processes and greenhouse gas emissions in soils.
Language: English
Subfield: Soil Science
Domain: Life Sciences
SDGs: Climate action, Life on land
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: National Science Foundation, U.S. Department of Energy, Innovative Genomics Institute, Adaptive Biotechnologies, Fundação de Amparo à Pesquisa do Estado de São Paulo, Fundação Amazônia Paraense de Amparo à Pesquisa, Office of Science, Division of Environmental Biology, Division of Earth Sciences, Biological and Environmental Research, Lawrence Livermore National Laboratory, Pacific Northwest National Laboratory
Awards: G1088636562, G14554683, G1868812749, G2145270357, G234237240, G2435523549, G2812390658, Collaborative Research: How iron states impact temperature sensitivity of heterotrophic respiration in humid tropical soils, G295657101, G3239266384, G4172109343, G4250999059, G4461761953, Collaborative Research: The Role of Iron Redox Dynamics in Carbon Losses from Tropical Forest Soils, Luquillo CZO: The role of hot spots and hot moments in tropical landscape evolution and functioning of the critical zone, G4991962395, G5111571831, G5315069497, G574795485, G8163035529, G8973980987, G991281326
OpenAlex ID: W4408053490