Pristine New Zealand forest soil is a strong methane sink
Pristine New Zealand forest soil is a strong methane sink
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DOI：
10.1046/j.1529-8817.2003.00710x
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发表时间：
2004-01-01
影响因子：
11.6
通讯作者：
Condron, LM
中科院分区：
文献类型：
--
作者：
Price, SJ;Sherlock, RR;Condron, LM
甲烷营养细菌在森林土壤中氧化甲烷（CH4），这些土壤覆盖了地球陆地表面的30%。这里报告了对南半球原始森林的首次测量。土壤CH4氧化速率（F-CH4）平均为10.5+/-0.6 kg CH4公顷（-1）年（-1），在干燥温暖的土壤中速率最大（高达17 kg CH4公顷（-1）年（-1））。甲烷营养活动主要集中在有机层以下50 ~ 100 mm深度。土壤含水量是F-CH4的主要调节因子（r(2)=0.88），从最常见的田间容量值降至土壤最干燥时的一半以下。多元线性回归分析表明，土壤温度对其影响不大。然而，逆共变率混淆了土壤水和温度效应在原位的分离。菲克定律解释了水含量在调节甲烷氧化菌气体扩散和底物供应中的作用，以及孔径分布和扭曲度的重要性。该分析还表明，在研究中使用的腔室不影响氧化率的测量。在长达17个月的研究中，土壤一直是大气中CH4的净汇，没有测量到CH4（或氧化亚氮，N2O）的净排放量。对于新西兰，我们的数据的全国范围外推表明，有可能抵消约90万头反刍动物排放的13%的甲烷。我们的平均F-CH4比大多数北半球森林土壤报告的速率高约6.5倍。这种非常高的F-CH4归因于至少3000-5000年来缺乏人为干扰和大气氮沉积速率低。我们真正的基线数据可以代表温带地区农业前、工业前土壤汇的有效估计。
Methanotrophic bacteria oxidize methane (CH4) in forest soils that cover similar to30% of Earth's land surface. The first measurements for a pristine Southern Hemisphere forest are reported here. Soil CH4 oxidation rate (F-CH4) averaged 10.5+/-0.6 kg CH4 ha(-1) yr(-1), with the greatest rates in dry warm soil (up to 17 kg CH4 ha(-1) yr(-1)). Methanotrophic activity was concentrated beneath the organic horizon at 50-100 mm depth. Water content was the principal regulator of F-CH4 (r(2)=0.88) from the most common value of field capacity to less than half of this when the soil was driest. Multiple linear regression analysis showed that soil temperature was not very influential. However, inverse co-variability confounded the separation of soil water and temperature effects in situ. Fick's law explained the role of water content in regulating gas diffusion and substrate supply to the methanotrophs and the importance of pore size distribution and tortuosity. This analysis also showed that the chambers used in the study did not affect the oxidation rate measurements. The soil was always a net sink for atmospheric CH4 and no net CH4 (or nitrous oxide, N2O) emissions were measured over the 17-month long study. For New Zealand, national-scale extrapolation of our data suggested the potential to offset 13% of CH4 emissions from ca. 90 M ruminant animals. Our average F-CH4 was about 6.5 times higher than rates reported for most Northern Hemisphere forest soils. This very high F-CH4 was attributed to the lack of anthropogenic disturbance for at least 3000-5000 years and the low rate of atmospheric nitrogen deposition. Our truly baseline data could represent a valid preagricultural, preindustrial estimate of the soil sink for temperate latitudes.