[WATER][RESOURCE][ENVIRONMENT] Trace gas cycling and soil carbon budgets in rewetted upland mires of Exmoor National Park

埃克斯穆尔国家公园的高地获得了每年降雨量的相当大一部分，这些降雨量为艾克斯河流域的50万消费者提供了水。这一地区还包括大片退化的泥炭地，这些泥炭地在19世纪和20世纪被排水和泥炭砍伐破坏。西南水务公司管理Exe流域的水资源，并正在投资于沼泽恢复，目的是改善供水的质量和数量。沼泽再湿的众多好处之一是有可能改变与大气的痕量气体交换的平衡，从而导致全球变暖潜力(GWP)的净减少。目前，土地所有者不会因为将退化的沼地恢复到自然潮湿状态而获得经济奖励。它们不会因为水质或水量的改善而获得金钱上的好处，也不会因为提高土壤固碳速率或净减少温室气体排放而获得报酬。这项研究的动机是，西南水务公司需要量化全球升温潜能值的净变化以及由于高地泥潭重新湿润而导致的水量和水质的改善，目的是获得资金，以奖励使退化的泥炭地区域可供恢复的土地所有者。一个由环境局和埃克塞特大学运营的项目(由西南水务公司资助)正在进行中，以解决供水和水质问题。这位布里斯托尔开放案例博士生将研究红外吸收气体二氧化碳、甲烷和一氧化二氮在相同的两个水源集水区的循环，这两个集水区已经为水研究提供了仪器。该项目的目的是量化这些关键温室气体在沟渠堵塞前后的大气和河流通量，以确定沼泽再湿对全球变暖潜势的净影响。这项研究的一个重要方面将是估计通量数据中的误差和不确定性，更具体地说，估计重新湿润后在土壤中建立生物地球化学平衡的时间表以及恢复前基线通量的年际变化范围。前一个问题将通过甲烷稳定同位素组成的变化来解决，甲烷的稳定同位素组成随泥炭地的营养和曝气状况而变化，可用于监测土壤生物地球化学功能的恢复。在研究期间，将在邻近未恢复的流域的站点进行通量测量，以评估恢复前基线通量的年际变化，因为在试验流域开始堵塞沟渠之前，只可能测量一年的地表和河流通量。这位博士生将与西南水务公司的工作人员合作，建立全球变暖净变化的货币值(基于二氧化碳当量的交易)。在这项研究的最终结果出来之前，CASE合作伙伴可能会利用这些信息就水务监管机构(Ofwat)设定的2015-2020年水价限制为土地所有者提供金钱奖励进行谈判。其动机是建立一个长期的激励制度，鼓励更多的土地所有者允许退化的泥炭地区域恢复，以造福于更广泛的社会。

The uplands of Exmoor National Park receive a considerable proportion of the annual rainfall that supplies water to >500,000 consumers in the River Exe catchment. This area also contains large tracts of degraded peatland that were damaged by drainage and peat cutting in the 19th and 20th centuries. South West Water plc manage the water resources of the Exe Catchment and are investing in mire restoration for the purpose of improving the quality and quantity of water supplies. Amongst the numerous benefits of mire rewetting is the potential to alter the balance of trace gas exchange with the atmosphere to cause a net reduction in Global Warming Potential (GWP). Landowners at present do not receive financial reward for converting degraded moorland back to a natural wet state. They receive no monetary benefit for improvements in water quality or quantity, nor are they paid for enhancing rates of soil carbon sequestration or a net reduction of greenhouse gas emissions. The motivation for this study is South West Water plc's need to quantify net changes in GWP and improvements in water quantity and quality due to rewetting of upland mires for the purpose of securing funds to reward landowners that make areas of degraded peatland available for restoration. A project operated by the Environment Agency and Exeter University (and funded by South West Water plc) is underway to address the water supply and quality questions. The Bristol Open CASE PhD student will study cycling of the infrared absorbing gases carbon dioxide, methane and nitrous oxide in the same two headwater catchments that have been instrumented for the water study. The aim of this project is to quantify atmospheric and fluvial fluxes of these key greenhouse gases before and after ditch-blocking to determine the net impact of mire rewetting on GWP. An important aspect of the study will be to estimate errors and uncertainties in the flux data, more specifically, the timeline for establishing biogeochemical equilibrium in the soils after rewetting and the range of inter-annual variation in pre-restoration baseline fluxes. The former issue will be addressed using changes in the stable isotope composition of methane which varies with trophic and aeration status in peatlands and can be used to monitor the restoration of soil biogeochemical function. During the study, flux measurements will be made at stations in adjacent unrestored catchments to assess inter-annual variability in pre-restoration baseline fluxes because it will be possible to measure only one year of surface and fluvial fluxes before ditch-blocking begins in the test catchments. The PhD student will work with staff at South West Water plc to establish a monetary value (based upon trading of CO2 equivalents) for net changes in GWP. Pending the final outcomes of this study, the information may be used by the CASE Partner to negotiate monetary rewards for landowners in the 2015-2020 water price limits set by the Water Services Regulation Authority (Ofwat). The motivation is to establish a long-term system of incentives that will encourage more landowners to allow areas of degraded peatland to be restored for the wider benefit of society.