Collaborative Research (ETBC): Climate Warming and Northern Peatland Decomposition, Accumulation and Carbon Sequestration Examined Through Molecular and Paleohydrological Analysis

合作研究（ETBC）：通过分子和古水文分析检查气候变暖和北部泥炭地的分解、积累和碳封存

• 批准号: 0843417
• 负责人: Ronald Benner
• 金额: $ 39.86万
• 依托单位: University South Carolina Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0843417&HistoricalAwards=false
• 关键词: Collaborative; Research; ETBC; Climate; Warming

The widespread occurrence of northern peatlands (above 50°N) is a distinctive and important attribute of the subarctic system that has global ramifications. The net sequestration of atmospheric carbon in northern peatlands (274-489 Pg C) has played a significant role in the global carbon cycle during the Holocene and will continue to be an important factor in the carbon cycle of the Anthropocene. A clearer understanding of how climate affects peat accumulation and decomposition rates, and ultimately net carbon sequestration, is critical for predicting how current and future warming will impact northern peatlands and the global carbon cycle. We propose a novel approach to gain a mechanistic understanding of the role of climate warming on rates of peat decomposition and net accumulation in a network of cores collected from the West Siberian Lowland (Russia), under a previous NSF-supported project, and the James Bay Lowland (Canada), under a separate NSF-supported project. Net rates of peat accumulation and carbon sequestration will be calculated from radiocarbon-dated cores. Hydrological changes, represented by changes in water table depth, will be directly calculated for the core sites using testate amoebae analysis. Detailed chemical characterizations of peat samples will be used to develop molecular indicators of peat decomposition. These molecular indicators and diagenesis models will then be applied to quantify rates and extent of peat decomposition and the relative importance of production and decomposition in determining carbon sequestration rates. Instrumental climate data and published paleoclimate research will be used to examine linkages among climate, hydrology, decomposition and accumulation and the mechanisms controlling the balance between peat production and decomposition. In view of current and anticipated warming of the subarctic over the next century, the proposed studies will focus on the Holocene Thermal Maximum (~8,000-4,000 Cal yr BP), the Medieval Warm Period (~1,100 to 700 Cal yr BP) and the comparative impacts of Modern Warming. Climate warming is having a disproportionately large affect on the hydrology, biota and biogeochemical cycles of the subarctic system. Northern peatlands have been major players in soil and atmospheric carbon cycling during the Holocene, and this study will provide a clearer picture of how climate shapes these processes. Novel approaches and potentially transformative concepts will be developed to provide a quantitative understanding of the mechanisms controlling carbon sequestration and release in northern peatlands. The research will provide a data base of over 20,000 detailed assays on past and present peatland biogeochemical conditions from ~40 core sites and ~100 surface sites in Siberia and central Canada. This project will provide training, experience and support for a postdoctoral associate in Benner?s laboratory at USC and a graduate student in MacDonald?s laboratory at UCLA. They will present their data at scientific meetings and prepare articles for publication in peer-reviewed journals. Benner and MacDonald teach undergraduate and graduate classes that cover various aspects of the global carbon cycle and climate change, and data collected from this project will be used as specific examples in these classes. This approach of bringing information from active research programs into the classroom has proven to be very effective for increasing student awareness and interest in science. An undergraduate student will be recruited to participate in this project (Benner?s laboratory) as part of the Magellan Scholars program at USC to provide research experiences for undergraduates. Results will be posted on research websites and data contributed to appropriate national and international data bases for widespread use.

北峰地带（高于50°N）的宽度出现是北极系统的独特而重要的属性，具有全球影响。北峰地（274-489 pg c）在大气碳中的净隔离在全新世期间在全球碳循环中发挥了重要作用，并将继续成为人类世碳循环的重要因素。对气候如何影响峰值积累和分解速率以及最终净碳会议的更清晰了解对于预测当前和未来的变暖将如何影响北山峰和全球碳循环。我们提出了一种新的方法，以在先前由NSF支持的项目和詹姆斯湾低地（加拿大的詹姆斯湾低地（加拿大），在一个单独的NSF支持的项目下，在从西西伯利亚低地（俄罗斯）收集的核心网络中，气候变暖对峰值分解和净积累速率的作用有一种机械理解。峰值积累和碳疫苗的净率将根据放射性碳日期计算。水文变化以地下水位深度变化为代表，将使用遗传变形虫分析直接计算核心位点。峰样品的详细化学特征将用于开发果皮分解的分子指标。然后，这些分子指标和成岩化模型将用于量化泥炭分解的速率和程度，以及生产和分解在确定碳频率速率中的相对重要性。乐器攀岩数据和已发表的古气候研究将用于检查气候，水文学，分解和积累之间的联系以及控制泥炭生产与分解之间平衡的机制。鉴于下一世纪亚北极的当前和预期的变暖，拟议的研究将集中于全新世热最大值（〜8,000-4,000 cal yr bp），中世纪的温暖时期（〜1,100至700 cal yr bp）和现代变暖的比较影响。气候变暖对亚北极系统的水文学，生物地球化学周期的影响不成比例。在全新世期间，北部的泥炭地一直是土壤和大气碳循环的主要参与者，这项研究将更清楚地了解如何攀登这些过程。将开发新的方法和潜在的变革概念，以提供对控制碳疗程和释放北部泥炭地的机制的定量理解。这项研究将提供有关过去和现在的泥炭地生物地球化学条件的20,000多种详细测定的数据库，来自约40个核心地点，西伯利亚和加拿大中部约100个地表地点。该项目将为UCLA的Benner实验室和麦克唐纳的一名研究生提供培训，经验和支持。他们将在科学会议上展示他们的数据，并准备在同行评审期刊上发表的文章。 Benner和MacDonald教学本科生和研究生班涵盖了全球碳循环和气候变化的各个方面，以及从该项目中收集的数据将被用作这些类别的特定示例。事实证明，这种将活跃研究计划的信息带入课堂的方法非常有效地提高学生对科学的认识和兴趣。作为USC麦哲伦学者计划的一部分，将招募一名本科生参加该项目（Benner的实验室），以为本科生提供研究经验。结果将发布在研究网站上，并有助于适当的国家和国际数据库以供广泛使用。