Manganese limitations and the enhanced soil carbon sequestration of temperate rainforests

Manganese (Mn) has been identified as a regulatory bottleneck in the accumulation of humus because of its role as an enzymatic co-factor in the breakdown of recalcitrant C by Mn-peroxidase (MnP). We tested this abiotic limit on decay via contrasting soils along a podzolization gradient of coastal British Columbia, where an inverse exponential relationship between soil organic carbon (SOC) and exchangeable Mn had been observed. Moderately weathered soils (Brunisols) had an average 3.6-fold increase in MnP activity within the upper soil profile in comparison to highly weathered Podzols. An ordination of the Agaricomycete fungal community, which are responsible for MnP production in soils, confirmed significant differences in assemblages across soil types for saprotrophic fungi, particularly species within the Agaricales, Trechisporales and Auriculariales. Ectomycorrhizal fungi of Pseudotsuga menziesii were equally aligned with soil type and select taxa more abundant on Brunisols may have ...