An ombrotrophic bog as a methane reservoir
An ombrotrophic bog as a methane reservoir
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作为甲烷库的营养沼泽
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
D. Kushner
中科院分区：
文献类型：
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作者：
Ann Brown;S. P. Mathur;D. Kushner
利用真空瓶和采样管从不同深度提取甲烷，考察了甲烷在一个营养型沼泽中的分布。在24平方米的区域内，在75分钟内从60厘米、90厘米和120厘米的深度提取甲烷。不同样品的甲烷提取量差异很大，而且这种差异在每个深度内比在不同深度之间更大。在90厘米和120厘米深度发现的甲烷大约是60厘米深度的2.5倍。从地表以下60厘米以上的地方产生的甲烷量可以与实验室孵育期间从同一地点的泥炭微生物产生的甲烷量相关联。从近地表泥炭中提取的甲烷要比从深层泥炭中提取的少得多，但在实验室中，从这一层提取的泥炭产生的甲烷是深层泥炭的10倍。我们的研究结果表明，在深50cm以下的疏养沼泽中存在大量的甲烷，我们在研究中计算出的甲烷量为1.7 Gg，我们认为这些甲烷通过堵塞土壤孔隙空间和阻止流体运动来降低泥炭下部的水力导电性；这反过来又产生了一个升高的地下水位，从而形成了一个凸起的沼泽。我们进一步建议，如果这些泥炭受到采矿或农业的干扰，被困的甲烷可能会释放到大气中，并增加温室气体对大气的污染。
The distribution of methane in an ombrotrophic bog was examined by extracting the gas from different depths, using evacuated bottles and sampling tubes. Methane was extracted during 75 min, from 60 cm, 90 cm and 120 cm depths at 25 stations in a 24 meter-square area. The amount of methane extracted varied widely between samples, and this variation was greater within each depth than between the different depths. Approximately two and a half times as much methane was found at 90 cm and 120 cm depths as at 60 cm. The amount of methane from sites more than 60 cm below the surface can be correlated with the methane microbially produced from peat from the same site during laboratory incubations. Much less methane could be extracted from near-surface peat than from deeper levels, but laboratory incubations of peat from this level produced 10-fold more methane. Our results show that there is a considerable amount of methane trapped below 50 cm depth within an ombrotrophic bog, which we calculate in the bog studied to be 1.7 Gg. We suggest this entrapped methane reduces the hydraulic conductivity in the lower layers of the peat by blocking the soil pore spaces and preventing fluid movement; this in turn generates an elevated water table allowing the formation of a raised bog. We further suggest that if this peat is disturbed by mining or farming, the entrapped methane could be released into the atmosphere and add to the atmospheric pollution by greenhouse gases.