Rhizosphere activity and atmospheric methane concentrations drive variations of methane fluxes in a temperate forest soil
Rhizosphere activity and atmospheric methane concentrations drive variations of methane fluxes in a temperate forest soil
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DOI：
10.1016/j.soilbio.2017.10.037
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发表时间：
2018
影响因子：
9.7
通讯作者：
J. Subke;C. Moody;T. Hill;N. R. Voke;S. Toet;P. Ineson;Y. Teh
中科院分区：
文献类型：
--
作者：
J. Subke;C. Moody;T. Hill;N. R. Voke;S. Toet;P. Ineson;Y. Teh
由于甲烷氧化菌的作用，通气土壤是大气甲烷（CH4）的重要汇，从而减缓了当前大气CH4的增加。虽然CH4氧化速率与植被覆盖类型有关，但植物与土壤之间的相互作用与土壤CH4汇的强度之间的相互作用还没有系统的研究。我们使用准连续自动化室测量土壤CH4和CO2通量从土壤衣领治疗，选择性地包括根和外生菌根（ECM）菌丝体调查根际活动的作用，以及其他环境驱动因素对CH4吸收在温带针叶林土壤。我们还评估了测量偏差的潜在影响，从零星室测量改变估计土壤CO2排放和CH4吸收。结果表明，活根和ECM菌丝体对土壤CO2排放和CH4吸收的存在下，一个明确的效果。ECM菌丝单独（无植物根）的存在下，表现出中间通量的CO2和CH4相对于土壤，无论是根和ECM菌丝体，或土壤缺乏根和ECM菌丝体。回归分析证实了土壤水分和温度对CH4和CO2通量动态的显著影响。我们进一步发现了一个令人惊讶的增加，土壤CH4吸收在夜间，并讨论昼夜波动的大气CH4（在夜间稳定的大气条件下，浓度较高）作为一个潜在的驱动程序的CH4氧化速率。使用我们的数据集的高时间分辨率，我们表明，低频采样的结果在系统偏差的放大通量估计，导致在我们的研究站点的低估高达20%，由于通量动态的波动，以及较长的时间尺度。
Aerated soils represent an important sink for atmospheric methane (CH4), due to the effect of methanotrophic bacteria, thus mitigating current atmospheric CH4increases. Whilst rates of CH4oxidation have been linked to types of vegetation cover, there has been no systematic investigation of the interaction between plants and soil in relation to the strength of the soil CH4sink. We used quasi-continuous automated chamber measurements of soil CH4and CO2flux from soil collar treatments that selectively include root and ectomycorrhizal (ECM) mycelium to investigate the role of rhizosphere activity as well as the effects of other environmental drivers on CH4uptake in a temperate coniferous forest soil. We also assessed the potential impact of measurement bias from sporadic chamber measurements in altering estimates of soil CO2efflux and CH4uptake. Results show a clear effect of the presence of live roots and ECM mycelium on soil CO2efflux and CH4uptake. The presence of ECM hyphae alone (without plant roots) showed intermediate fluxes of both CO2and CH4relative to soils that either contained roots and ECM mycelium, or soil lacking root- and ECM mycelium. Regression analysis confirmed a significant influence of soil moisture as well as temperature on flux dynamics of both CH4and CO2flux. We further found a surprising increase in soil CH4uptake during the night, and discuss diurnal fluctuations in atmospheric CH4(with higher concentrations during stable atmospheric conditions at night) as a potential driver of CH4oxidation rates. Using the high temporal resolution of our data set, we show that low-frequency sampling results in systematic bias of up-scaled flux estimates, resulting in under-estimates of up to 20% at our study site, due to fluctuations in flux dynamics on diurnal as well as longer time scales.