An evaluation of plant wax markers to reconstruct long-term vegetation change in peat bog deposits

集中在北方和亚北极地区的北方泥炭地储存了全球土壤碳的三分之一，是非常重要的全球二氧化碳汇，储存的碳量占目前大气CO2水平的25-50%。在未来全球变暖的情况下，它们继续封存二氧化碳的能力及其植物成分尚不确定，但对它们在以前气候变化期间储存碳的能力的研究可以为它们未来的潜在反应提供线索。已经表明，在中世纪温暖期和小冰期期间，泥炭沼泽中碳积累速率的变化取决于形成泥炭的植物的植物成分。因此，在调查碳积累的长期记录时，重建当地泥炭形成的植被是至关重要的，但不幸的是，这并不总是可能的，因为植物宏体化石在毯状泥炭沼泽和其他北方和亚北极泥炭地生态系统中保存得不好。有鉴于此，迫切需要开发替代技术，从广泛的泥炭沼泽档案沉积物中重建泥炭形成植物，其中包含碳积累速率变化的千年记录，并以这种方式重建碳封存的空间和时间变化。这项研究旨在纠正这个问题，通过测试的“分子化石”保存在泥炭剖面从英国毯泥炭剖面（保存的宏化石往往是穷人在这些存款）重建前植被成分的适用性。如果成功的话，这个项目的回报将是提高对以前气候变化时期依赖物种的碳固存的理解，这可能会证明非常有益于为国际和国家未来的碳管理提供信息（高沼地地区的泥炭沉积物是英国最大的陆地碳库）。改进泥炭沼泽植被变化的起源和性质的长期基线数据也将有助于指导和帮助保护这些受威胁的生态系统，特别是毯状泥炭沼泽。这将是非常有益的利益相关者负责水的收集，农业，体育，休闲和旅游业的高沼地栖息地泥炭沼泽栖息地发生。该技术有很好的前景，因为他们的应用在博士生试点项目提供了物种水平的识别（石楠）在埋土存款。测试植物蜡生物化学标记作为泥炭沼泽植被的替代物的价值将包括三个阶段。第一阶段将是确定从一系列凸起/毯状泥炭沼泽生境中收集的活的参考材料的化学标志物。随后将分析已知植物成分和年龄的亚化石样本，这些样本来自广泛的放射性碳年代测定的凸起泥炭沼泽剖面，具有良好的宏体化石保存。这些样品作为欧盟第六框架资助的主要项目（“Accrotelm”）的一部分进行了研究，它们的及时可用性代表了研究已知植物组成样品的化石植物蜡生物化学特征的绝佳机会。来自已知植物物种的现代/亚化石植物蜡生物化学标记物的数据将用于概念阶段的最后证明，以重建不完全已知植物成分的毯状泥炭样品的潜在前当地植被。泥炭沼泽沉积物包含了碳固存率变化的详细记录，也提供了替代气候数据和长期生态记录，为保护政策提供信息。英国科学家在这些矿床的分析方面处于世界领先地位，这个小型项目与NERC目前的三个战略科学主题密切相关，即生物多样性，自然资源的可持续利用和利益相关者的知识交流。

Northern peatlands concentrated in boreal and subarctic regions store as much as one-third of global soil carbon and represent a highly important global carbon dioxide sink, with an amount of stored carbon representing 25-50% of current levels of atmospheric CO2. Their ability to continue to sequester carbon dioxide and their botanical composition under future global warming scenarios is uncertain, but research into their ability to store carbon during former periods of climate change can provide clues to their potential future response. It has already been shown that changes in the rate of carbon accumulation during the Medieval Warm Period and Little Ice Age in raised peat bogs was dependent upon the botanical composition of the peat forming plants. It is therefore vital to reconstruct the local peat forming vegetation when investigating long-term records of carbon accumulation, but this, unfortunately is not always possible, as plant macrofossils do not preserve well in blanket peat bogs and other boreal and subarctic peatland ecosystems. Given this, there is a pressing need to develop alternative techniques to reconstruct peat forming plants from extensive peat bog archive deposits which contain millennial records of carbon accumulation rate changes, and in this way reconstruct the spatial and temporal variability of carbon sequestration. This research seeks to redress this problem by testing the suitability of 'molecular fossils' preserved in peat profiles from UK blanket peat profiles (preservation of macrofossils is frequently poor in these deposits) to reconstruct the former vegetation components. If successful, the reward of this project will be improved understanding of species dependent carbon sequestration during previous periods of climate change, which could prove highly beneficial to inform future carbon management, both internationally and nationally (peat deposits in moorland areas represent the largest terrestrial carbon pool in the UK). Improved long-term base line data for the origin and nature of vegetation changes in peat bogs would also serve to guide and aid conservation of these threatened ecosystems, particularly blanket peat bogs. This would be highly beneficial to stakeholders charged with water collection, agriculture, sport, leisure, and tourism in moorland habitats where peat bog habitats occur. The techniques have excellent promise since their application in a PhD pilot project offered species level identification (of heather) in a buried soil deposit. Testing the value of plant wax biochemical markers as a proxy for peat-bog vegetation will involve three stages. The first stage will be to determine the chemical markers of living, reference material collected from a range of raised/blanket peat bog habitats. This will be followed by analyses of sub-fossil samples of known botanical composition and age from an extensively radiocarbon dated raised peat bog profile with excellent macrofossil preservation. These samples were investigated as part of a major EU 6th Framework funded project ('Accrotelm') and their timely availability represent an excellent opportunity to investigate the fossil plant wax biochemical signatures of samples of known botanical composition. Data on the modern/sub-fossil plant wax biochemical markers from known plant species will then be used in the final proof of concept stage to reconstruct the potential former local vegetation of a blanket peat sample of imperfectly known botanical composition. Peat bog deposits contain detailed records of carbon sequestration rate changes, and also provide proxy-climate data and long-term ecological records to inform conservation policies. UK scientists are world leaders in the analyses of these deposits, and this small project is closely aligned with three of NERC's current strategic science themes on Biodiversity, Sustainable Use of Natural Resources, and Knowledge Exchange to stakeholders.