Spatio‐temporal changes in bog pool bottom topography – temperature effect and its influence on pool development: an example from a raised bog in Estonia
Spatio‐temporal changes in bog pool bottom topography – temperature effect and its influence on pool development: an example from a raised bog in Estonia
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沼泽池底部地形的时空变化——温度效应及其对池发育的影响：以爱沙尼亚凸起沼泽为例
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
H. Tõnisson
中科院分区：
文献类型：
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作者：
E. Karofeld;H. Tõnisson
夏季池水和泥炭温度的升高加速了泥炭的分解和生物成因气体的产生，这些生物气体可以被困在泥炭孔隙中，导致泥炭表面的振荡和泥炭从沼泽池底上升。泥炭导水率、持水量和蒸腾作用的相关变化也会影响沼泽水文。我们的多年研究首次详细展示了沼泽池深度和底部地形随温度、泥炭类型和其他因素变化的程度和动态。一旦池底水温超过13-14 °C，泥炭从池底开始真正的季节性上升，尽管上升的速度和程度取决于泥炭的性质，使上升比随后的下降更不稳定。在夏季末，由于甲烷产量的减少和气体溶解度的增加，在受泥炭性质影响较小的情况下，池水表面温度首次大幅下降后，下降速度更快。从池底向池面上升的泥炭孔隙水中溶解有机碳浓度(2 16 ± 2 6 mg L−1)明显高于池底同一类型泥炭的溶解有机碳浓度(62 ± 20 mg L−1)，表明较暖的池面泥炭分解速度加快。我们展示了水池深度和底部地形变化的程度和特征，以及年度差异与温度的关系。池水温度每升高几度，池底抬升的速度就会更快，范围更广，池面泥炭分解的速度也会加快。应该更详细地评估这一点，以评估气温上升对泥炭地碳收支和水文的影响。版权所有©2012 John Wiley&Sons，Ltd.
Increases in pool water and peat temperature in summer accelerate peat decomposition and production of biogenic gases, which can be trapped in peat pores and cause oscillation of peatland surfaces and the rise of peat from the bottom of bog pools. Associated changes in peat water conductivity, holding capacity and transpiration also affect bog hydrology. Our multi‐year study is the first to show in detail the extent and dynamics of changes in bog pool depth and bottom topography associated with changes in temperature, peat type and other factors. The true seasonal rise of peat from the pool bottom begins once the water temperature at the pool bottom exceeds 13–14 °C, although the speed and extent of the rise depends on peat properties, making the rise more erratic than its subsequent descent. The more rapid descent occurs after the first large drop in the temperature of the pool's surface water at the end of summer, resulting from the combination of reduced methane production and increased gas solubility with less influence by peat properties. Much higher dissolved organic carbon concentrations (216 ± 26 mg l−1) in the pore water of peat risen from the bottom to the pool surface compared with that in the same type of peat at the pool bottom (62 ± 20 mg l−1) indicate an acceleration of peat decomposition at the warmer pool surface. We show the extent and character of changes in pool depth and bottom topography and how annual differences relate to temperature. Only a few degrees' increase in pool water temperature could induce the pool bottom to rise faster and more extensively for a longer period and enhance decomposition in the peat at the pool surface. This should be evaluated in greater detail to assess the effects of temperature increase on the carbon budget and hydrology of peatlands. Copyright © 2012 John Wiley & Sons, Ltd.