Differential peat deformation, compressibility, and water storage between peatland microforms: Implications for ecosystem function and development
Differential peat deformation, compressibility, and water storage between peatland microforms: Implications for ecosystem function and development
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泥炭地微形态之间的差异泥炭变形、压缩性和储水量：对生态系统功能和发展的影响
DOI：
10.1029/2009wr008802
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发表时间：
2010
影响因子：
5.4
通讯作者：
J. Price
中科院分区：
文献类型：
--
作者：
J. Waddington;E. Kellner;M. Strack;J. Price
由于泥炭是有弹性的，泥炭表面的日常和季节性的膨胀和收缩不仅影响了水的储存，而且还改变了泥炭的水力以及泥炭的生物地球化学和热学性质。由于不同的植物学起源和分解程度，我们假设不同的泥炭微型体(山脊和草坪)在泥炭变形和可压缩性方面表现出很大的差异。在这里，我们研究了加拿大魁北克泥炭地沿5米样带的低草坪(LL)、上草坪(UL)和山脊(R)的泥炭表面移动、泥炭强度和体积含水率的空间变化。泥炭表层的平均季节幅度在L1、UL和R站点分别为9、6和2厘米。这些地点的表层都相当坚硬，泥炭厚度的最大变化发生在泥炭剖面的20至60厘米深处。在不同的土层中，压缩系数各不相同，但与土层内的其他性质无关。然而，当考虑到平均剖面可压缩性时，它与泥炭深度、von后腐殖化、到中空的距离和泥炭强度显著相关。地下水位以下膨胀的总蓄水量与土壤水分亏缺(降水减去蒸散量)基本相同，而旱地尤其是旱地的储水量亏缺较小。考虑到本季度圈闭气体含量的变化，减少了对所有地点蓄水量变化的估计。由于微相类型和位置是水物理性质的显著预测因子，我们认为这表明泥炭地微地形通过生态水文反馈而自我强化。在泥炭地生态水文模型中纳入这些特性的可变性将是预测泥炭地生态系统对干扰的响应的关键。
Because peat is elastic, the daily to seasonal swelling and shrinking of the peat surface not only affects water storage but also alters peatland hydraulics and the biogeochemical and thermal properties of peat. Due to different botanical origins and degrees of decomposition, we hypothesized that different peatland microforms (ridges and lawns) display a large variation in peat deformation and compressibility. Here we examined the spatial variation of peat surface movement, peat strength, and volumetric water content at a low lawn (LL), upper lawn (UL), and ridge (R) along a 5 m transect in a peatland in Quebec, Canada. The average seasonal amplitude in peat surface level was 9, 6, and 2 cm at the LL, UL, and R sites, respectively. The surface layers in each of these sites were fairly rigid with the largest changes in peat thickness occurring between 20 and 60 cm depth in the peat profile. Compressibility varied among microforms but was not correlated to other properties within the layer in individual soil layers. However, when average profile compressibility was considered, it was significantly correlated to peat depth, von Post humification, distance to hollow, and peat strength. The total water storage by dilation below the water table was about the same as the water deficit (precipitation minus evapotranspiration) for LL, while the storage deficit for UL and especially R was lower. Including changes in entrapped gas content over the season reduced estimates of changes in water storage at all sites. Because microform type and position were significant predictors of hydrophysical properties, we argue that this suggests that peatland microtopography is self‐reinforcing through ecohydrological feedbacks. Including the variability in these properties in peatland ecohydrological models will be key for predicting the response of peatland ecosystems to disturbance.