Stendahl Johan, Berg Björn, Lindahl Björn D
Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, SE-75007, Uppsala, Sweden.
Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Helsinki, Finland.
Sci Rep. 2017 Nov 14;7(1):15487. doi: 10.1038/s41598-017-15801-y.
Carbon sequestration below ground depends on organic matter input and decomposition, but regulatory bottlenecks remain unclear. The relative importance of plant production, climate and edaphic factors has to be elucidated to better predict carbon storage in forests. In Swedish forest soil inventory data from across the entire boreal latitudinal range (n = 2378), the concentration of exchangeable manganese was singled out as the strongest predictor (R = 0.26) of carbon storage in the extensive organic horizon (mor layer), which accounts for one third of the total below ground carbon. In comparison, established ecosystem models applied on the same data have failed to predict carbon stocks (R < 0.05), and in our study manganese availability overshadowed both litter production and climatic factors. We also identified exchangeable potassium as an additional strong predictor, however strongly correlated with manganese. The negative correlation between manganese and carbon highlights the importance of Mn-peroxidases in oxidative decomposition of recalcitrant organic matter. The results support the idea that the fungus-driven decomposition could be a critical factor regulating humus carbon accumulation in boreal forests, as Mn-peroxidases are specifically produced by basidiomycetes.
地下碳固存取决于有机质的输入和分解，但监管瓶颈仍不明确。必须阐明植物生产、气候和土壤因素的相对重要性，以便更好地预测森林中的碳储量。在瑞典整个北方纬度范围内（n = 2378）的森林土壤清查数据中，可交换锰的浓度被确定为广泛的有机层（粗腐殖质层）中碳储量的最强预测因子（R = 0.26），该有机层占地下总碳的三分之一。相比之下，应用于相同数据的现有生态系统模型未能预测碳储量（R < 0.05），在我们的研究中，锰的有效性超过了凋落物产量和气候因素。我们还确定可交换钾是另一个强有力的预测因子，不过它与锰高度相关。锰与碳之间的负相关突出了锰过氧化物酶在难降解有机物质氧化分解中的重要性。这些结果支持了这样一种观点，即真菌驱动的分解可能是调节北方森林腐殖质碳积累的关键因素，因为锰过氧化物酶是担子菌特有的产物。
