Hogg Edward H, Lieffers Victor J, Wein Ross W
Ecol Appl. 1992 Aug;2(3):298-306. doi: 10.2307/1941863.
Global warming and the resultant increase in evapotranspiration might lead to lowered water tables in peatlands and an increase in fire frequency. The objective of this study was to investigate some of the potential effects of these changes on peat decomposition. Dry mass losses and emissions of CO and CH from peat samples taken from three depth layers (0-10, 10-20, and 30-40 cm) of a black spruce peatland were measured in the laboratory at 8°, 16°, and 24°C under two moisture treatments. Effects of deep peat fire on decomposition were also simulated by burning the upper layer (0-10 cm) of peat and adding the ash to peat samples from the 10-20 cm layer. CH release averaged <1% of total carbon loss in flooded samples. Release of CO was 4-9 times greater from the 0-10 cm layer than from the 30-40 cm layer. After 120 d, the 30-40 cm layer had lost <1% of its original dry mass in all treatments. Higher temperatures strongly promoted decomposition of samples exposed to drying cycles but had little effect on decomposition of continuously flooded samples. Ash addition had variable effects on CO emissions but may have promoted CH production. It is suggested that in certain situations, global warming may not cause appreciable increases in carbon loss from peat deposits. The results indicate that some deeper peats are resistant to decay even when exposed to warm, aerobic conditions. However, further experimental work is needed to predict the long-term response of peat deposits to changes in water levels in different peatland types.
全球变暖和由此导致的蒸散增加可能会导致泥炭地地下水位下降以及火灾频率上升。本研究的目的是调查这些变化对泥炭分解的一些潜在影响。在实验室中，于8℃、16℃和24℃的温度条件下，对取自黑云杉泥炭地三个深度层（0 - 10厘米、10 - 20厘米和30 - 40厘米）的泥炭样品进行两种水分处理，测量其干质量损失以及CO和CH的排放。还通过燃烧泥炭上层（0 - 10厘米）并将灰烬添加到10 - 20厘米层的泥炭样品中，模拟深层泥炭火灾对分解的影响。在水淹样品中，CH释放量平均占总碳损失的<1%。0 - 10厘米层的CO释放量比30 - 40厘米层高4 - 9倍。120天后，在所有处理中，30 - 40厘米层的原始干质量损失<1%。较高温度强烈促进了经历干燥循环的样品的分解，但对持续水淹样品的分解影响不大。添加灰烬对CO排放有不同影响，但可能促进了CH的产生。研究表明，在某些情况下，全球变暖可能不会导致泥炭沉积物的碳损失显著增加。结果表明，即使暴露在温暖、有氧的条件下，一些较深的泥炭也具有抗腐烂能力。然而，需要进一步的实验工作来预测不同泥炭地类型中泥炭沉积物对水位变化的长期响应。
