The impact of wildfire on microbial C:N:P stoichiometry and the fungal-to-bacterial ratio in permafrost soil
The impact of wildfire on microbial C:N:P stoichiometry and the fungal-to-bacterial ratio in permafrost soil
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DOI：
10.1007/s10533-018-0510-6
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发表时间：
2018-10
期刊：
影响因子：
4
通讯作者：
Xuan Zhou;Huiguo Sun;J. Pumpanen;Outi‐Maaria Sietiö;J. Heinonsalo;Kajar Köster;F. Berninger
中科院分区：
文献类型：
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作者：
Xuan Zhou;Huiguo Sun;J. Pumpanen;Outi‐Maaria Sietiö;J. Heinonsalo;Kajar Köster;F. Berninger
野火融化了北方森林近地表的永久冻土层，使以前冻结的有机物可供微生物利用。野火后的短期微生物化学计量学动态对理解冻土融化过程中土壤元素的变化至关重要。因此，我们选择了一个连续多年冻土带地区的北方野火时间序列，其中最后一次野火发生在3、25、46和100年前（作为对照），以探索野火对土壤化学、土壤微生物化学计量学和真菌-细菌基因比（F:B比）的影响。我们观察到微生物生物量C:N:P比值在不同年龄类别中保持不变，这表明微生物在化学计量比方面是稳态的。当C:N大于12时，微生物C:N不受菌菌比变化的影响。野火导致的植被生物量减少对真菌的基因拷贝数有积极影响，而对细菌的基因拷贝数没有积极影响。火灾后微生物生物量C、N和P的下降主要是由于土壤有效碳和养分的缺乏。在土壤深度为30 cm时，野火对微生物生物量和F:B比均无影响。我们得出结论，微生物化学计量并不总是对真菌与细菌比例的变化做出反应，野火引起的永久冻土融化并不会加速微生物呼吸。
Wildfires thaw near-surface permafrost soils in the boreal forest, making previously frozen organic matter available to microbes. The short-term microbial stoichiometric dynamics following a wildfire are critical to understanding the soil element variations in thawing permafrost. Thus, we selected a boreal wildfire chronosequence in a region of continuous permafrost, where the last wildfire occurred 3, 25, 46, and > 100 years ago (set as the control) to explore the impact of wildfire on the soil chemistry, soil microbial stoichiometry, and the fungal-to-bacterial gene ratio (F:B ratio). We observed the microbial biomass C:N:P ratio remained constant in distinct age classes indicating that microbes are homeostatic in relation to stoichiometric ratios. The microbial C:N ratios were independent of the shifts in the fungal-to-bacterial ratio when C:N exceeded 12. Wildfire-induced reduction in vegetation biomass positively affected the fungal, but not the bacterial, gene copy number. The decline in microbial biomass C, N, and P following a fire, primarily resulted from a lack of soil available C and nutrients. Wildfire affected neither the microbial biomass nor the F:B ratios at a soil depth of 30 cm. We conclude that microbial stoichiometry does not always respond to changes in the fungal-to-bacterial ratio and that wildfire-induced permafrost thawing does not accelerate microbial respiration.