Sensitivity of peatland litter decomposition to changes in temperature and rainfall
Sensitivity of peatland litter decomposition to changes in temperature and rainfall
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DOI：
10.1016/j.geoderma.2018.06.002
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发表时间：
2018-12
期刊：
影响因子：
6.1
通讯作者：
M. Bell;J. Ritson;A. Verhoef;R. Brazier;M. R. Templeton;N. Graham;C. Freeman;Joanna M. Clark
中科院分区：
文献类型：
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作者：
M. Bell;J. Ritson;A. Verhoef;R. Brazier;M. R. Templeton;N. Graham;C. Freeman;Joanna M. Clark
对许多泥炭地地区未来50 年的气候变化进行了预测。由于形成泥炭的植被的分解很可能与这些气候变化有着内在的联系，因此需要对气候-泥炭动态有一个清晰的认识。人们担心，气温升高和降水减少可能会加快分解速度，并使许多泥炭地的碳汇状况处于危险之中，但很少有研究对这两种气候因素的影响进行综合考察。为了更好地了解泥炭地分解对温度和降水变化及其相互作用的敏感性，我们进行了一项短期实验室实验，在析因设计中，将植物凋落物和泥炭土隔离培养。这些处理模拟了来自英国最新气候变化预测（UKCP09）的Exmoor的基线和预测气候平均值，Exmoor是英格兰西南部的一个气候边缘泥炭地。在整个模拟过程中进行了定期的二氧化碳通量测量，以及总质量损失和总溶解有机碳（DOC）浸出。在本多因素试验中，基质对碳损失的影响最大，泥炭/泥炭在试验期间释放的碳总量显著低于矮灌木/禾本科植物。气候效应是基质特异性的，干燥降雨处理增加了愈伤草的DOC淋出，但减少了藻的DOC淋出。co2和DOC之间的分配也受到气候的影响，但仅限于泥炭和sphagnumn样品，在这些样品中，未来的气候情景（更温暖和更干燥）导致更大比例的C以气态形式损失。这些结果表明，气候通过泥炭地物种组成变化的间接影响最终可能比温度升高和降雨量减少等气候变化的直接影响对凋落物分解更重要。
Changes to climate are projected over the next 50 years for many peatland areas. As decomposition of peat-forming vegetation is likely to be intrinsically linked to these changes in climate, a clear understanding of climate-peat dynamics is required. There is concern that increased temperature and decreased precipitation could increase the rate of decomposition and put the carbon sink status of many peatlands at risk, yet few studies have examined the impact of both climatic factors together. To better understand the sensitivity of peatland decomposition to changes in both temperature and precipitation and their interaction, we conducted a short-term laboratory experiment in which plant litters and peat soil were incubated, in isolation, in a factorial design. Treatments simulated baseline and projected climate averages derived from the latest UK climate change projections (UKCP09) for Exmoor, a climatically marginal peatland in SW England. Regular carbon dioxide flux measurements were made throughout the simulation, as well as total mass loss and total dissolved organic carbon (DOC) leached. The largest effect on carbon loss in this multifactor experiment was from substrate, withSphagnum/peat releasing significantly less C in total during the experiment than dwarf shrubs/graminoids. Climate effects were substrate specific, with the drier rainfall treatment increasing the DOC leaching fromCalluna, but decreasing it fromSphagnum. Partitioning between CO2and DOC was also affected by climate, but only for the peat andSphagnumsamples, where the future climate scenarios (warmer and drier) resulted in a greater proportion of C lost in gaseous form. These results suggest that indirect effects of climate through changes in species composition in peatlands could ultimately turn out to be more important for litter decomposition than direct effects of climate change from increased temperatures and decreased rainfall.