Geochemical control of organic matter turnover in peatlands: Long-term security or short-term vulnerability of a major carbon store?

泥炭地有机质周转的地球化学控制：主要碳储存的长期安全性还是短期脆弱性？

基本信息

批准号：
NE/E004709/1
负责人：
Lisa Belyea
金额：
$ 38.19万
依托单位：
Queen Mary University of London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FE004709%2F1
关键词：
Geochemical control organic matter turnover

项目摘要

Peatlands cover vast areas of the world - around 4 million square kilometres - and store about as much carbon as do the living plants in tropical rainforests. For the past 5,000-10,000 years, the plants living on peatlands have been fixing carbon dioxide from the atmosphere and storing it as dead plant matter - 'peat'. In a future warmer, and possibly drier, climate, this stored carbon could be respired back to the atmosphere or leached into rivers. Will increased temperatures and decreased rainfall lead to rapid loss of the peatland carbon store? If so, then the extra carbon released from peatlands could enhance 'greenhouse' warming further, leading to a runaway positive feedback on global climate. Or will rapid climate change trigger a shift to peatland types that accumulate peat (and store carbon) at a faster rate than present-day peatlands? If the latter, then peatlands could buffer further climate change. In this project, we will investigate the three-way interactions between plants, decomposition of peat and environmental factors such as temperature. Although there have been many studies on decomposition of forest and grassland soils, surprisingly little is known about how peat decays. We are particularly interested in how differences in the chemistry of different types of plants (and of the peat they produce) affects how quickly the peat decomposes and how it responds to changes in temperature. Of special concern is the bog-moss, Sphagnum, which has a unique chemical composition that makes it very resistant to decomposition. Our field site is a peatland in central Sweden that shows a great variety of plant types and environmental conditions, ranging from swamp forest to fen to bog. Using the full range of variation, we will analyse in detail the chemistry of a wide variety of living plants and their recently dead remains. We will also examine changes in chemistry and rates of peat accumulation in short cores that provide a historical record of the past 300 years or so. In addition, we will track how the chemistry of new and old peat changes as it decomposes, under higher temperatures and under drier conditions. The results of these studies will help us to predict how the peatland carbon store will fare in the face of future climate change.

泥炭地覆盖了世界广大地区（约400万平方公里），并存储着热带雨林中的活植物量的碳。在过去的5,000至10，000年中，生活在泥炭地上的植物一直从大气中固定二氧化碳，并将其作为死植物物质 - “泥炭”储存。在未来的温暖，可能更干燥的气候中，这种存储的碳可以回到大气或浸入河流中。温度和降雨量下降会导致泥炭地碳店迅速损失吗？如果是这样，那么从泥炭地释放的额外碳可以进一步增强“温室”的变暖，从而导致对全球气候的积极反馈。还是快速的气候变化会引发向泥炭地类型的转变，而泥炭地类型会比当今的泥炭地更快地累积泥炭（并存储碳）？如果后者，那么泥炭地可能会缓冲气候变化。在这个项目中，我们将研究植物之间的三向相互作用，泥炭的分解和环境因素（例如温度）。尽管已经进行了许多关于森林和草原土壤分解的研究，但令人惊讶的是，关于泥炭腐烂的方式知之甚少。我们对不同类型的植物（以及它们产生的泥炭的化学差异）的差异特别感兴趣，这会影响泥炭分解的速度及其对温度变化的反应。特别令人担忧的是沼泽 - 泥石用，它具有独特的化学成分，使其对分解非常抗性。我们的野外场地是瑞典中部的泥炭地，显示了各种各样的植物类型和环境条件，从沼泽森林到沼泽，再到沼泽。使用各种差异，我们将详细分析各种各样的生物及其最近死亡遗体的化学反应。我们还将研究短核的化学变化和泥炭积聚的变化，这些岩心可提供过去300年左右的历史记录。此外，我们将跟踪新泥炭和旧泥炭分解，在较高温度和较干燥条件下的化学变化。这些研究的结果将有助于我们预测面对未来气候变化的泥炭地碳店如何表现。