Effects of temperature and water table on the efflux of methane from peatland surface cores
Effects of temperature and water table on the efflux of methane from peatland surface cores
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DOI：
10.1016/s1352-2310(98)00078-8
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发表时间：
1998-10-01
影响因子：
5
通讯作者：
Clymo, RS
中科院分区：
文献类型：
--
作者：
Daulat, WE;Clymo, RS
(1)从凸起的沼泽的生活表面切割直径为30 cm、深为40 cm的圆柱形岩心，并将其安装在相同直径的桶中。将岩心保存在室外，用蒸馏水保持其天然水位，直到转移到恒温室进行实验。通过四极质谱法测量气体通量和浓度分布。(2)浓度分布图显示，在地下水位以下约15厘米处有一个强烈的甲烷源，分布图中的峰值随地下水位上下移动。源可以在几个小时内打开和关闭。(3)CHL的流出指数依赖于（摄氏）温度，是20%以上的光比它是在黑暗中，即使当表面植被是泥炭藓没有任何维管植物。(4)流出空心，草坪，和丘微生境负线性依赖于地下水位的深度。三种微生境的关系斜率基本相同。(5)当Menyanthes trifoliata（沼泽）是存在于空洞的流出量是大于当只有泥炭藓存在。氩的运动表明，在泥炭和大气之间，月牙兰的根和枝提供了一个高电导的路线。(6)现场温度，降水量和地下水位记录的水文（10月至9月）年苏格兰西南部的沼泽地。使用实验确定的关系和测得的温度和地下水位计算CH4的预期流出量。这些计算值的平均值与测量值的平均值一致，尽管单个点分散。(C)1998爱思唯尔科技有限公司版权所有。
(1) Cylindrical cores, 30 cm diameter by 40 cm deep, were cut from the living surface of a raised bog and installed in buckets of the same diameter. The cores were kept outdoors, and their natural water levels maintained with distilled water, until transfer to constant temperature rooms for experiments. Gas fluxes and concentration profiles were measured by quadrupole mass spectrometry. (2) Concentration profiles show that there is an intense source of CH4 about 15 cm below the watertable, and that peaks in the profile move up and down with the watertable. The source can be turned on and off in a few hours. (3) The efflux of CHL depends exponentially on (Celsius) temperature, and is 20% greater in light than it is in the dark, even when the surface vegetation is Sphagnum moss without any vascular plants. (4) Efflux from hollow, lawn, and hummock microhabitats depends negatively and linearly on the depth of the watertable. The slope of the relation is almost the same in ail three microhabitats. (5) When Menyanthes trifoliata (bogbean) is present in hollows the efflux is greater than when only Sphagnum is present. The movement of argon shows that the roots and shoots of Menyanthes provide a high-conductance route between the peat and the atmosphere. (6) Field temperature, precipitation and watertable were recorded for a hydrological (Oct-Sept) year on a raised bog in southwest Scotland. Expected efflux of CH4 was calculated using the experimentally determined relations and the measured temperature and watertable. The mean of these calculated values agreed with the mean of measured values, though individual points were scattered. (C) 1998 Elsevier Science Ltd. All rights reserved.