Testing the role of nutrient input thresholds in governing microbial-mediated carbon sequestration for temperate peatlands

测试养分输入阈值在控制温带泥炭地微生物介导的碳封存中的作用

• 批准号: NE/X010635/1
• 负责人: Daniel Schillereff
• 金额: $ 7.75万
• 依托单位: King's College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX010635%2F1
• 关键词: Testing; role; nutrient; input; thresholds

Our research will shed new light on the ways nutrient input (primarily phosphorus and nitrogen) controls how efficiently temperate, ombrotrophic peatlands store carbon. Our recent synthesis of the few peatlands with well-dated and parallel core profiles of phosphorus, nitrogen and carbon underpinned a new conceptual model of long-term peatland carbon cycling (Schillereff et al. 2021). Ombrotrophic (rain-fed) peatlands derive nutrients primarily via atmospheric deposition, so nutrient input maintains the tight balance between primary productivity and the decomposition of organic matter by microbes. We therefore hypothesised that nutrient input thresholds govern how efficiently and how much carbon becomes sequestered in peatlands over decades, centuries and millennia. Our study highlighted two research gaps preventing our conceptual model being tested: i) measurements of the activity and diversity of microbial communities are strikingly absent from palaeoenvironmental peat research and (ii) surprisingly few peatlands have parallel measurements for all nodes of the peatland carbon cycle: climate, vegetation, nutrients, microbes and carbon. Our proposal will implement an innovative research design to test our conceptual model. Working at four carefully selected temperate, ombrotrophic peatlands in the UK and Sweden where we have established research portfolios, we will integrate some of the first DNA characterisation of down-core microbial dynamics with high-resolution reconstructions of each other node of the peatland carbon cycle spanning the last 2000 years. This will enable our hypothesis that nutrient input thresholds govern long-term peatland carbon sequestration to be empirically tested for the first time. To deliver these objectives, we will: (i) collect new peat cores from four sites and perform DNA characterisation of their microbial communities at regular depths; (ii) complete high-resolution measurements of each other node at King's College London, University of Liverpool, Stockholm University and the NERC Environmental Omics Facility; (iii) apply statistical modelling to quantify the role of and interplay between each driver of peatland carbon cycling. Site selection (Holcroft and May Moss, England; Store and Draftinge Mosse, Sweden) is guided by our extensive baseline data and strategically captures gradients of nutrient deposition, altitude and land-use. By combining in an innovate way cutting-edge metagenomic characterisation of microbial activity with conventional measurements of other drivers, we will produce a more complete picture of peatland carbon cycling. Globally, peatlands are a significant carbon store, containing one-third of the soil carbon pool. Peatlands sequester carbon efficiently because their waterlogged, nutrient impoverished conditions slow the decomposition of organic matter relative to the productivity of surface vegetation. This also means small changes in nutrient input can trigger significant shifts in carbon storage. Human activities have amplified P and N deposition in recent decades, which has changed the nutrient limitation status and carbon cycling in other terrestrial ecosystems. The implications for the future peatland carbon sink remain unclear. As well as establishing a testbed for our conceptual model, the findings should stimulate deeper integration between the peatland ecology, soil microbiology and global carbon cycling research communities. We intend our findings to underpin ambitious future research aimed at better understanding the resilience of temperate peatlands to both 21st-century climate and biogeochemical change. This will involve parameterising new numerical models of peatland development that encapsulate nodes for climate, vegetation, nutrients, microbes and carbon. Subsequent integration into Earth System models should produce more representative trajectories for peatland carbon through the 21st-century. Schillereff et al. 2021, Comms. Earth & Env. 2:1-10

我们的研究将为营养素输入（主要是磷和氮）控制如何有效温带，杂菌营养泥炭储存碳的养分输入方式。我们最近对磷，氮，碳和碳的日期良好且平行的核心曲线的少数泥炭地的合成为长期泥炭地碳循环的新概念模型（Schillereff etal。2021）提供了新的概念模型。杂菌营养（雨水）泥炭地主要通过大气沉积来得出营养，因此养分输入保持了一级生产力与微生物分解有机物之间的紧密平衡。因此，我们假设养分输入阈值控制了数十年，几个世纪和千年的泥炭地的有效性和碳含量的效率和含量。我们的研究强调了两个研究差距，阻止了我们的概念模型的测试：i）在古环境泥炭研究中，显着缺乏微生物群落的活性和多样性的测量，并且（ii）令人惊讶的是，很少有泥炭地对泥炭碳循环的所有节点进行平行测量：气候，蔬菜，营养，营养，微生物和Carbon，Carbon和Carbon。我们的建议将实施创新的研究设计，以测试我们的概念模型。在英国和瑞典的四个精心挑选的温带杂质泥炭地工作，我们将在我们建立研究组合中工作，我们将将下核微生物动力学的一些DNA表征与跨越过去2000年的山顶碳循环的彼此相结合的高分辨率重建。这将使我们的假设是，营养输入阈值控制长期的泥炭地碳螯合，以首次进行经验测试。为了实现这些目标，我们将：（i）从四个地点收集新的泥炭核心，并在常规深度对其微生物群落进行DNA表征； （ii）在伦敦国王学院，利物浦大学，斯德哥尔摩大学和NERC环境无障碍设施的彼此节点的完整高分辨率测量； （iii）应用统计建模来量化泥炭兰碳循环的每个驱动器之间的作用和相互作用。现场选择（英格兰的Holcroft和May Moss；商店和瑞典的Mosse）受到我们广泛的基线数据的指导，并战略性地捕获了养分沉积，高度和土地使用的梯度。通过以创新的方式结合微生物活性的最先进的宏基因组表征，并将其用于其他驱动因素的常规测量，我们将对泥炭地碳循环产生更完整的图片。在全球范围内，泥炭地是一家重要的碳店，其中包含土壤碳池的三分之一。泥炭地有效地隔离了碳，因为它们的水洗，营养贫困的条件减慢了有机物相对于表面植被的生产力的分解。这也意味着养分输入的微小变化可以触发碳存储的显着变化。近几十年来，人类活动扩大了P和N的沉积，这改变了其他陆地生态系统中的养分限制状况和碳循环。对未来泥炭地碳汇的影响尚不清楚。除了为我们的概念模型建立测试床外，这些发现还应刺激泥炭地生态学，土壤微生物学和全球碳循环研究社区之间的更深层次的整合。我们打算以雄心勃勃的未来研究为基础的发现，旨在更好地了解温带泥炭地对21世纪气候和生物地球化学变化的弹性。这将涉及参数的泥炭地发育的新数值模型，该模型封装了气候，植被，养分，微生物和碳的节点。随后的地球系统模型的整合应通过21世纪为泥炭地碳产生更多的代表性轨迹。 Schillereff等。 2021，通讯。 Earth＆Env。 2：1-10