One year of continuous measurements of soil CH4 and CO2 fluxes in a Japanese cypress forest: Temporal and spatial variations associated with Asian monsoon rainfall
One year of continuous measurements of soil CH4 and CO2 fluxes in a Japanese cypress forest: Temporal and spatial variations associated with Asian monsoon rainfall
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DOI：
10.1002/2014jg002851
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发表时间：
2015-04
期刊：
影响因子：
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通讯作者：
Ayaka Sakabe;Y. Kosugi;Kenshi Takahashi;Masayuki Itoh;Akito Kanazawa;N. Makita;M. Ataka
中科院分区：
文献类型：
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作者：
Ayaka Sakabe;Y. Kosugi;Kenshi Takahashi;Masayuki Itoh;Akito Kanazawa;N. Makita;M. Ataka
我们研究了亚洲季风降雨对水不饱和森林土壤吸收CH4的影响。为了研究CH4通量随土壤环境的变化规律，在3个不同土壤特征和含水量的样地，采用自动化室内系统对土壤CH4和CO2通量进行了为期1年的连续测量。CH4吸收受“白”夏季降雨事件的影响而减少，在随后的干热期达到峰值。虽然CH4吸收和CO2排放随土壤温度的升高而增加，但CH4对温度的依赖性大于对CO2的依赖性，这可能是由于甲烷氧化菌和产甲烷菌之间的活动平衡在一个较宽的温度范围内发生变化，这受到土壤含水量的强烈影响。在短时间间隔（30min）内，各样地CH4和CO2通量对降雨的响应不同。在腐殖质层较厚的干燥土壤中，两种通量在降雨强度达到峰值时均急剧下降。降雨后CO2排放量迅速增加，而CH4吸收量逐渐增加。地下累积CO2的释放以及土壤与空气之间CH4和CO2交换的限制和恢复决定了通量对降雨的响应。在湿土样地和腐殖质层较薄的干土样地，CH4通量没有突然减少。因此，亚洲季风降雨强烈影响CH4通量的时间变化，而不同样地对环境因子的通量响应差异导致CH4通量的年收支变化较大。
We examined the effects of Asian monsoon rainfall on CH4 absorption of water‐unsaturated forest soil. We conducted a 1 year continuous measurement of soil CH4 and CO2 fluxes with automated chamber systems in three plots with different soil characteristics and water content to investigate how temporal variations in CH4 fluxes vary with the soil environment. CH4 absorption was reduced by the “Baiu” summer rainfall event and peaked during the subsequent hot, dry period. Although CH4 absorption and CO2 emission typically increased as soil temperature increased, the temperature dependence of CH4 varied more than that of CO2, possibly due to the changing balance of activities between methanotrophs and methanogens occurring over a wide temperature range, which was strongly affected by soil water content. In short time intervals (30 min), the responses of CH4 and CO2 fluxes to rainfall were different for each plot. In a dry soil plot with a thick humus layer, both fluxes decreased abruptly at the peak of rainfall intensity. After rainfall, CO2 emission increased quickly, while CH4 absorption increased gradually. Release of accumulated CO2 underground and restriction and recovery of CH4 and CO2 exchange between soil and air determined flux responses to rainfall. In a wet soil plot and a dry soil plot with a thinner humus layer, abrupt decreases in CH4 fluxes were not observed. Consequently, the Asian monsoon rainfall strongly influenced temporal variations in CH4 fluxes, and the differences in flux responses to environmental factors among plots caused large variability in annual budgets of CH4 fluxes.