Impacts of warming on boreal peatland microbial community structure and function

泥炭地含有一层厚厚的有机层，由部分腐烂的植物材料组成，是巨大的碳库，储存了全球约15%-30%的土壤碳。几千年来，泥炭地一直是全球碳汇，但这些生态系统受到气候变化因素的干扰，如气温上升、二氧化碳水平上升和降水制度的变化，可能会导致它们成为碳源。北部地区，包括加拿大发现的泥炭地，被认为特别容易受到气候变暖的影响。泥炭地变暖和干燥可以降低地下水位，从而增加微生物和中型动物分解者对土壤氧气的利用率，将有机碳分解为二氧化碳。泥炭地不仅会受到气候变暖的影响，还会与极端天气事件等其他气候压力因素一起受到影响。目前尚不清楚多种环境因素对泥炭地土壤微生物结构和功能的影响。在这个项目中，我们计划调查气候变暖对泥炭地生态系统的影响，重点是土壤微生物群落结构和分解过程的变化。我们将把土壤微生物的这些变化与中型动物群落的变化和更广泛的土壤食物网动态联系起来。最后，我们将使用西方大学独特的、高度受控但符合环境现实的生物群室，研究多种气候变化因素(如二氧化碳、温度、降水)如何影响泥炭地微生物群落结构和功能。我们计划使用BRLACE(生物对不断变化的星球的反应)变暖操纵实验(西方大学、安大略省自然资源和林业部-安大略省森林研究所和加拿大林业局五大湖中心的合作项目)，其中位于安大略省怀特河附近的两个泥炭地在过去三年中经历了实验变暖，并拥有15年的广泛监测数据。这项长期的野外实验使我们能够确定气候变暖如何改变泥炭地土壤中的微生物群落结构和功能。这两个地点的植被类型不同；一个地点以泥炭苔藓为主，另一个地点以苔草为主，这是最常见的北方泥炭地生境类型。因此，我们还能够研究地上群落结构如何影响地下对气候变暖的反应。该项目将使我们能够了解气候变化将如何影响微生物群落及其功能(例如分解、温室气体通量)，这对土壤食物网稳定性的影响，以及某些泥炭地栖息地是否对环境变化更具弹性。这些经验数据可用于为政策制定者和缓解战略提供信息。

NERC : Katy Faulkner : NE/L002493/1Peatlands contain a thick organic layer of partially decayed plant material and are huge carbon stocks, storing around 15-30% of soil carbon worldwide. Peatlands have acted as global carbon sinks for many millennia, but disturbance of these ecosystems from climate change factors such as increasing temperatures, rising CO2 levels and alterations of precipitation regimes could result in them becoming carbon sources. Northern regions, including peatlands found in Canada, are thought to be particularly vulnerable to climate warming. Warming and drying in peatlands could lower the water table and therefore increase the soil oxygen availability for microbial and mesofauna decomposers which break down the organic carbon to CO2. Peatlands will not be affected by warming alone, but in combination with other climate stressors such as extreme weather events. The effects of multiple environmental factors on peatland soil microbial structure and function is not currently known. In this project, we plan to investigate the impacts of warming on peatland ecosystems focussing on changes to soil microbial community structure and decomposition processes. We will link these changes in the soil microbiology to the changes in mesofauna communities and the wider soil food web dynamics. Finally, we will investigate how multiple climate change factors (e.g. CO2, temperature, precipitation) will impact peatland microbial community structure and function using unique, highly controlled but environmentally realistic biome chambers at Western University. We plan to use the BRACE (Biological Response to A Changing Planet) warming manipulation experiment (a collaborative project between Western University, Ontario Ministry of Natural Resources and Forestry-Ontario Forest Research Institute and the Canadian Forest Service Great Lakes Centre) where two peatland sites, located near White River, Ontario, have undergone experimental warming for the past three years and have 15 years of extensive monitoring data. This long-term field experiment allows us to determine how warming alters microbial community structure and function in peatland soils. The two sites differ in their vegetation type; one site is dominated by Sphagnum moss and the other is a Carex sedge dominated site, which are the most commonly found boreal peatland habitat types. We are therefore also able to address how aboveground community structure impacts the belowground response to warming. This project will enable us to understand how microbial communities and their functions (e.g. decomposition, greenhouse gas fluxes) will be impacted by climate change, the implications of this on soil food web stability and whether certain peatland habitats are more resilient to environmental change. This empirical data can be used to inform policymakers and mitigation strategies.