Boreal forest soils are important global carbon sinks, with significant storage in the organic topsoil. Decomposition of these stocks requires oxidative enzymes, uniquely produced by fungi. Across Swedish boreal forests, we found that local carbon storage in the organic topsoil was 33% lower in the presence of a group of closely related species of ectomycorrhizal fungi – Cortinarius acutus s.l.. This observation challenges the prevailing view that ectomycorrhizal fungi generally act to increase carbon storage in soils but supports the idea that certain ectomycorrhizal fungi can complement free-living decomposers, maintaining organic matter turnover, nutrient cycling and tree productivity under nutrient-poor conditions. The indication that a narrow group of fungi may exert a major influence on carbon cycling questions the prevailing dogma of functional redundancy among microbial decomposers. Cortinarius acutus s.l. responds negatively to stand-replacing disturbance, and associated population declines are likely to increase soil carbon sequestration while impeding long-term nutrient cycling.

中文翻译：

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一组外生菌根真菌限制北方森林有机质积累

北方森林土壤是重要的全球碳汇，在有机表土中具有大量储存。这些原料的分解需要由真菌独特产生的氧化酶。在整个瑞典北方森林中，我们发现在存在一组密切相关的外生菌根真菌物种——Cortinarius acutus的情况下，有机表土中的局部碳储存量降低了 33%SL。这一观察结果挑战了普遍的观点，即外生菌根真菌通常会增加土壤中的碳储存，但支持某些外生菌根真菌可以补充自由生活的分解者，在营养贫乏的条件下维持有机物质周转、养分循环和树木生产力的观点。一小群真菌可能对碳循环产生重大影响的迹象质疑微生物分解者之间功能冗余的普遍教条。Cortinarius acutus sl 对林分替代干扰产生负面反应，相关的种群下降可能会增加土壤碳固存，同时阻碍长期养分循环。