Soil Methane Sink Capacity Response to a Long-Term Wildfire Chronosequence in Northern Sweden.
Soil Methane Sink Capacity Response to a Long-Term Wildfire Chronosequence in Northern Sweden.
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DOI：
10.1371/journal.pone.0129892
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Ostle NJ
中科院分区：
文献类型：
--
作者：
McNamara NP;Gregg R;Oakley S;Stott A;Rahman MT;Murrell JC;Wardle DA;Bardgett RD;Ostle NJ
北方森林占陆地面积的近五分之一，被认为是全球重要的碳循环和温室气体排放调节器。这些森林中的碳固存过程包括将CO2同化为生物量，随后转化为土壤有机质，以及土壤微生物对甲烷（CH4）的氧化。在这项研究中，我们探讨了生态系统退化，这驱动植被变化，调节土壤CH4氧化的重要过程中，在北方森林。我们测量了一组30个森林岛屿在瑞典北方不同的火灾历史，并共同代表一个倒退的时序，跨越5000年的土壤甲烷氧化过程。在这些岛屿的土壤有机质的积累，观察到随着时间的推移，因为火灾干扰，更大的腐殖质深度和增加的净土壤甲烷氧化率之间的显着相关性。我们认为，在没有干扰的情况下，这种净CH4氧化率的增加，结果作为更深的腐殖酸存储积累，并提供生态位甲烷氧化菌茁壮成长。通过使用这个梯度，我们发现了重要的监管控制土壤甲烷氧化过程的稳定性，不能没有探索通过短期实验。我们的研究结果表明，在没有人为干预，如灭火，并增加野火频率，全球重要的北方CH4汇可能会减少。
Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished.