Modelling environmental change impacts on peat accumulation in northern peatlands

泥炭地是在其土壤(泥炭)中积累了大量有机物质的生态系统，因为它们经常处于水分饱和状态。在淹水的条件下，分解速度会大大降低，因此垃圾积累的速度比分解的速度要快。泥炭可以堆积数千年，高度可达几米。泥炭地仅占全球陆地表面的3%左右，但在加拿大，泥炭地覆盖了很大一部分地貌(约12%)，特别是在北部低地和土壤永久冻结的地区(永久冻土)。*泥炭地负责许多生态系统服务，包括为野生动物提供栖息地和调节水质。它们在气候系统中也扮演着重要的角色，因为泥炭由大约50%的碳(干重)组成。因此，它们在全球范围内储存了大量的碳，相当于目前在大气中发现的碳量。由于泥炭地位于正在经历快速变化的地区，包括广泛的气候变暖和基础设施发展，它们提供的生态系统服务可能在未来几十年内发生重大变化。生态系统服务的这些变化可能会影响生活在北方的加拿大人的环境和生计，并进一步影响全球气候系统的稳定。**我的研究重点是气候变化对北方泥炭地气候调节功能的影响。我的总体目标是回答以下两个问题：气候如何影响北部泥炭地的植被组成、内部过程和碳积累；以及未来气候、永久冻土、区域水文和养分可获得性的变化将如何影响它们的碳平衡？**我使用两个主要研究工具来回答这些问题。我利用泥炭地所拥有的独特属性来记录和保存数千年的生态和气候变化，以重建泥炭积累的变化。我将泥炭积累的变化与环境变化联系起来，例如永久冻土融化或养分供应的变化。这项工作将在位于不同地区(加拿大的西北地区、安大略省东部；瑞典北部)的三个不同地点进行。我还使用计算机模拟来综合我从重建中学到的东西，并预测未来几十年和几个世纪可能会发生什么泥炭堆积。对于这项研究，我将扩展一个已经存在的简单的泥炭积累模拟模型，以包括永久冻土和与养分相关的过程。**我希望我的研究结果将显著提高对影响泥炭长期积累的因素的理解，从而更好地理解泥炭地未来在气候系统中的作用。这反过来将使人们能够更好地预测朝鲜未来的环境变化。

Peatlands are ecosystems that accumulate a significant amount of organic matter in their soils (peat) because they are constantly water-saturated. Decomposition rates are greatly reduced in waterlogged conditions, so litter accumulates faster than it decomposes. Peat can accumulate for thousands of years and reach several meters in height. Peatlands cover only about 3% of the global land surface, but in Canada they cover significant portions of the landscape (~12 %), especially in the northern lowlands and in zones where the soil is permanently frozen (permafrost). **Peatlands are responsible for many ecosystem services, including providing habitats to wildlife and regulating water quality. They also have an important role in the climate system, as peat is composed of approximately 50% of carbon (dry weight). They therefore store a significant quantity of carbon globally, equivalent to the amount of carbon currently found in the atmosphere. As peatlands are located in areas undergoing rapid changes, including widespread climate warming and infrastructure development, the ecosystem services they provide might be significantly modified in the next few decades. These changes in ecosystem services may impact the environment and livelihood of the Canadians living in the North and further affect the stability of the global climatic system. **My research is focused on the impact that climate change will have on the climate regulating function of northern peatlands. My overall goal is to answer the following two questions: how is climate affecting the vegetation composition, internal processes and carbon accumulation of northern peatlands; and how will future changes in climate, permafrost, regional hydrology and nutrient availability affect their carbon balance? **I address these questions using two main research tools. I use the unique property that peatlands have to record and conserve thousands of years of ecological and climatic changes to reconstruct changes in peat accumulation. I relate peat accumulation variations to environmental changes such as permafrost thaw, or variations in nutrient availability. This work will be done in three different sites located in contrasting regions (Northwest Territories, Eastern Ontario in Canada; Northern Sweden). I also use computer simulations to synthesize what I learned from the reconstructions and to project what might happen to peat accumulation over the next decades and centuries. For this research, I will expand an already existing simple peat accumulation simulation model to include permafrost and nutrient-related processes.**I expect the results of my research to significantly improve the understanding of the factors governing long-term accumulation of peat, and therefore, to better understand the future role of peatlands in the climate system. This will in turn allow a better forecasting of future environmental changes in the North.