Soil Redox Controls CO 2 , CH 4 and N 2 O Efflux from White-Rot Fungi in Temperate Forest Ecosystems.

Microaerophilic white-rot fungi (WRF) are impacted by oxygen depletion because of fluctuating redox occurrence in southern temperate forest soils of Chile (1500-5000 mm year ^-1 ). How these conditions influence WRF survival has been scarcely examined. We explored the contributions of WRF to greenhouse gas (GHG) emissions of N ₂ O and CH ₄ and soil organic C oxidation (CO ₂ ) in five sterilized and inoculated forest soils derived from various parent materials and climates. The soil was incubated for 20 days following (i) oxic, (ii) anoxic, and (iii) fluctuating redox conditions. Fungi contributed to 45% of the total GHG under redox fluctuating conditions, including the contribution of bacteria, while the opposite (26%) was valid for oxic treatment. On average, the highest gas emission (62%) was N ₂ O for WRF under redox treatment, followed by anoxic (22%) and oxic (16%) treatments, while CO ₂ and CH ₄ emissions followed oxic > redox > anoxic. These data suggest that indigenous microbial WRF communities are well adapted to fluctuating redox milieu with a significant release of GHG emissions in humid temperate forests of the southern cone.