Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon EX4 4RJ, United Kingdom.
Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom.
Sci Total Environ. 2014 Sep 15;493:961-73. doi: 10.1016/j.scitotenv.2014.06.091. Epub 2014 Jul 8.
Losses of dissolved organic carbon (DOC) from drained peatlands are of concern, due to the effects this has on the delivery of ecosystem services, and especially on the long-term store of carbon and the provision of drinking water. Most studies have looked at the effect of drainage in deep peat; comparatively, little is known about the behaviour of shallow, climatically marginal peatlands. This study examines water quality (DOC, Abs(400), pH, E4/E6 and C/C) during rainfall events from such environments in the south west UK, in order to both quantify DOC losses, and understand their potential for restoration. Water samples were taken over a 19 month period from a range of drains within two different experimental catchments in Exmoor National Park; data were analysed on an event basis. DOC concentrations ranging between 4 and 21 mg L(-1) are substantially lower than measurements in deep peat, but remain problematic for the water treatment process. Dryness plays a critical role in controlling DOC concentrations and water quality, as observed through spatial and seasonal differences. Long-term changes in depth to water table (30 days before the event) are likely to impact on DOC production, whereas discharge becomes the main control over DOC transport at the time scale of the rainfall/runoff event. The role of temperature during events is attributed to an increase in the diffusion of DOC, and therefore its transport. Humification ratios (E4/E6) consistently below 5 indicate a predominance of complex humic acids, but increased decomposition during warmer summer months leads to a comparatively higher losses of fulvic acids. This work represents a significant contribution to the scientific understanding of the behaviour and functioning of shallow damaged peatlands in climatically marginal locations. The findings also provide a sound baseline knowledge to support research into the effects of landscape restoration in the future.
从排水的泥炭地中流失的溶解有机碳 (DOC) 令人担忧，因为这会影响生态系统服务的提供，特别是对碳的长期储存和饮用水的供应。大多数研究都集中在深层泥炭上的排水影响；相比之下，对气候边缘的浅层泥炭地的行为知之甚少。本研究考察了英国西南部此类环境中降雨事件期间的水质 (DOC、Abs(400)、pH 值、E4/E6 和 C/C)，以便量化 DOC 损失，并了解其恢复的潜力。在埃克斯穆尔国家公园的两个不同实验集水区内的一系列排水管中，在 19 个月的时间内采集水样；根据事件对数据进行了分析。DOC 浓度在 4 到 21mg/L 之间，远低于深层泥炭中的测量值，但对水处理过程仍然构成问题。干旱通过空间和季节性差异，在控制 DOC 浓度和水质方面起着至关重要的作用。水位深度的长期变化（事件发生前 30 天）可能会影响 DOC 的产生，而排放则成为降雨/径流事件时间尺度上 DOC 传输的主要控制因素。事件期间温度的作用归因于 DOC 扩散的增加，因此其运输也会增加。E4/E6 比值持续低于 5 表明复杂腐殖酸占主导地位，但在温暖的夏季，腐殖酸的分解会导致相对较高的损失。这项工作是对了解气候边缘地区浅层受损泥炭地行为和功能的重要科学贡献。研究结果还为支持未来景观恢复效果的研究提供了可靠的基线知识。
