Diffusion and mass flow of dissolved carbon dioxide, methane, and dissolved organic carbon in a 7-m deep raised peat bog
Diffusion and mass flow of dissolved carbon dioxide, methane, and dissolved organic carbon in a 7-m deep raised peat bog
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DOI：
10.1016/j.gca.2008.01.032
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发表时间：
2008-04-15
影响因子：
5
通讯作者：
Bryant, C. L.
中科院分区：
文献类型：
--
作者：
Clymo, R. S.;Bryant, C. L.
在65个样本中，我们在苏格兰西南部依赖雨水的隆起(穹顶)沼泽Ellergower Moss获得了浓度、C-14/C-13(AMS)年龄和增量C-13的值(对于这种类型的工作来说，这是异常可复制和一致的)：泥炭、溶解有机碳(DOC)、泥炭组分以及溶解的CO2和CH4，间隔50厘米，直到700厘米。(1)我们将结果的一致性归因于Ellergower Moss异常均匀，具有异常低的水力传导性，并且只包含少量气体空间；以及包括18个月的现场采样器平衡在内的采样方法。(2)尽管CO2浓度是CH4浓度的5-10倍，但溶解气体浓度深度剖面呈凸形，且非常相似，而DOC剖面呈凹形。(3)泥炭的年龄分布与深度几乎成线性关系，DOC的年龄分布比相同深度的泥炭年轻约500-1000岁，溶解气体比泥炭年轻500-4300年。可操作的泥炭组分腐植酸和胡敏素的年龄与整个泥炭的年龄相似。(4)深层泥炭的三角洲C-13剖面基本不变，三角洲C-13-CO2比泥炭更富集(三角洲C-13-CO2占35%)。更多)；三角洲C-13-CH4是相同数量的更枯竭的。靠近地表，两种溶解气体逐渐变得更加枯竭，C-13增量约为20%。在表面上更少。(5)模拟结果表明，质量流可以解释DOC的浓度和年龄分布，但气体的扩散和靠近地表的附加源也是必要的，扩散占溶解气体运移的99%以上。(6)同样的过程必须在其他泥炭地运行，但埃勒戈尔的结果不应不加批判地推论到它们。(C)2008爱思唯尔有限公司。保留所有权利。
In 65 samples, we got values (unusually replicable and consistent for this type of work) of concentration, C-14/C-13 (AMS) age, and delta C-13 for: peat, dissolved organic carbon (DOC), peat fractions, and dissolved CO2 and CH4 at 50-cm intervals down to 700 cm in Ellergower Moss, a rainwater-dependent raised (domed) bog in southwest Scotland. (1) We attribute the consistency of the results to Ellergower Moss being unusually homogeneous, with unusually low hydraulic conductivity, and containing only a few gas spaces; and to the sampling methods including 18-month equilibration of in situ samplers. (2) The dissolved gas concentration depth profiles are convex and very similar to each other, though CO2 is 5-10 times more concentrated than CH4, while the profile of DOC is concave. (3) The age profile of peat is near linearly proportional to depth; that for DOC is about 500-1000 yr younger than the peat at the same depth; the dissolved gases are 500-4300 years younger than the peat. The age of the operational peat fractions humic acid and humin is similar to that of whole peat. (4) The delta C-13 profile for deep peat is almost constant; delta C-13-CO2 is More enriched than the peat (delta C-13-CO2 35%. more); delta C-13-CH4 is the same amount more depleted. Nearer the surface both dissolved gases become steadily more depleted, delta C-13 is about 20%. less at the surface. (5) A simulation shows that mass flow can account for the concentration and age profiles of DOC, but for the gases diffusion and an additional source near the surface are needed as well, and diffusion accounts for over 99% of the dissolved gas movements. (6) The same processes must operate in other peatlands but the results for Ellergower should not be extrapolated uncritically to them. (c) 2008 Elsevier Ltd. All rights reserved.