Managing Peatlands as Carbon Stores

泥炭地包含大量陆生有机物，通过光合作用从大气中固定下来，因此是重要的碳储存库。然而，英国的许多泥炭地遭受了干扰，包括排水、农业改良、泥炭砍伐、造林、燃烧和大气养分沉积增加。这种扰动改变了泥炭地碳循环过程，导致土壤碳储量向大气释放增加。因此，国家和地区机构正在努力保护和恢复这些退化的泥炭地，以保存现有的碳储量（以帮助减缓气候变化），并保护野生动物栖息地和景观。修复通常涉及堵塞排水沟以提高地下水位，从而鼓励积水条件，使泥炭再次形成。人们认为，恢复减少了向大气和水环境的碳损失。然而，至少在短期内，它可能导致甲烷（CH4）排放量的增加，甲烷是一种比二氧化碳（CO2）更强的温室气体。当泥炭地的碳平衡以全球变暖潜势（GWP）表示时，CH4排放的增加可能会减少甚至超过与泥炭地恢复相关的碳节约。虽然有一些证据表明，恢复的泥炭地排放的二氧化碳比退化的泥炭地少得多，但由于泥炭地被认为排放更多的甲烷，因此恢复的泥炭地是否会成为以全球潜能值计算的碳汇仍存在相当大的不确定性。此外，泥炭地的含水碳通量很少（如果有的话）被视为泥炭地碳收支的一部分。因此，除了气态碳损失外，泥炭地的水碳损失的量化对于确定场地的碳预算以及了解恢复以减少碳损失和温室气体（GHG）通量的潜力至关重要。该项目将通过调查恢复如何影响疏养沼泽的碳汇功能来解决这一知识差距。这项研究将在索恩和哈特菲尔德摩尔进行，那里有现有的恢复计划、监测项目、数据集，以及来自英国自然协会的管理和学术帮助。具体而言，该研究将(i)调查(a)地下水位高度、(b)植被和(c)恢复以来的时间对CH4排放和全球变暖潜值的影响，以及（ii）阐明导致受阻排水沟渠排放高浓度CH4的过程和因素。该项目将为恢复实践如何影响泥炭地的碳预算和全球变暖潜值提供新的见解，其结果将用于改进英国和国际泥炭地恢复和管理的政策和指导方针，以缓解气候变化。它将为学生培训提供一个极好的一揽子方案，包括实地和实验室工作的要素，能够发展广泛的技术技能基础和泥炭地管理。这个项目的跨学科性质将为学生提供对他们未来的科学事业有很大价值的技能。实地考察将建立在现有的土壤和土壤水分监测项目的基础上，该项目是查普曼之前指导的博士项目的一部分。因此，我们有信心这个项目适合博士研究，我们对学生的期望是合适的。查普曼和贝尔德在博士指导和项目完成方面有着出色的记录，学生们在博士毕业后成功地走上了职业生涯。利兹大学与CASE合作伙伴自然英格兰之间的伙伴关系将为该项目的跨学科主题提供力量和深度，特别是泥炭地生态学、水文学、土壤科学、碳循环和泥炭地管理。

Peatlands comprise a large accumulation of terrestrial organic matter, fixed from the atmosphere by photosynthesis, and are, therefore, important carbon stores. However, many peatlands in the UK have suffered from disturbance, including drainage, agricultural improvement, peat cutting, afforestation, burning, and increased atmospheric nutrient deposition. Such disturbance has altered peatland carbon cycling processes and has led to increased release of the soil carbon stock to the atmosphere. Therefore, protection and restoration of these degraded peatlands is being pursued by national and regional agencies in order to conserve existing carbon stocks (to help mitigate climate change), and to protect wildlife habitats and landscapes. Restoration usually involves blocking of drainage ditches to raise the water table and hence encourage waterlogged conditions that will enable peat to form again. It is believed that restoration reduces carbon losses both to the atmosphere and the aqueous environment. However, it may lead to an increase in methane (CH4) emissions, at least in the short term, which is a more potent greenhouse gas than carbon dioxide (CO2). Increases in CH4 emissions may reduce or even outweigh carbon savings associated with peatland restoration, when the carbon balance of a peatland is expressed in terms of global warming potential (GWP). Although there is some evidence that restored peatlands emit much less CO2 than degraded peatlands, there is considerable uncertainty over whether or not restored peatlands become carbon sinks in GWP terms because they are thought to emit more CH4. In addition, aqueous fluxes of carbon from peatlands are rarely, if ever, considered as part of the peatland carbon budget. Quantification of aqueous carbon loss, in addition to gaseous carbon losses, from peatlands is, therefore, critical in determining carbon budgets for sites, and in understanding the potential of restoration to reduce carbon losses and green house gas (GHG) flux. This project will address this knowledge gap by investigating how restoration affects the carbon sink function of ombrotrophic bogs. The research will take place at Thorne and Hatfield Moors, where existing restoration schemes, monitoring programmes, data sets, and management and academic help from Natural England are available. In particular the research will (i) investigate the impact of (a) water table height, (b) sedges and (c) time since restoration on CH4 emissions and GWP and (ii) elucidate the processes and factors that account for the high rates of CH4 emitted from blocked drainage ditches. The project will deliver new insights into how restoration practices influence the carbon budget and GWP of peatlands and the results will be used to improve UK and international policy and guidelines on peatland restoration and management for climate mitigation. It will provide an excellent package for student training, incorporating elements of field and laboratory work, enabling the development of a broad technical skills base, and peatland management. The inter-disciplinary nature of this project will provide the student with skills that will be of great value to their future scientific career. The fieldwork will build on an existing soil and soil water monitoring programme installed as part of a previous PhD project supervised by Chapman. Therefore, we are confident that the project is suitable for PhD study and that our expectations of the student are appropriate. Chapman and Baird have an excellent track record of PhD supervision and project completion, with students going on to successful post-PhD careers. The partnership between Leeds and the CASE partner, Natural England, will provide strength and depth across the inter-disciplinary topics of the project, in particular, peatland ecology, hydrology, soil science, carbon cycling and peatland management.