Collaborative Research: How does the deep critical zone (CZ) structure impact the hydrology and coupled carbon cycling of northern peatlands?

合作研究：深层临界区（CZ）结构如何影响北部泥炭地的水文和耦合碳循环？

• 批准号: 2051350
• 负责人: Andrew Reeve
• 金额: $ 26.09万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2051350&HistoricalAwards=false
• 关键词: Collaborative; Research; How; does; deep

Northern peatlands are a unique type of wetland found in the northern United States and a dominant landform at higher latitudes, including Canada, northern Scandinavia and Russia. Industrial development has led to some peatlands being drained or burned to promote agriculture, construction or use for fuel. Today, peatlands are recognized as unique ecosystems that support a diverse range of plants not found elsewhere. Furthermore, they are an important part of a global carbon cycle trapping carbon dioxide in organic matter and storing approximately 33% of the total carbon found in soils. Peatlands release some of this carbon to the atmosphere as methane, a potent greenhouse gas. Although the ecology of peatlands is well studied, the geological controls on peatland development and the percolation patterns of peatland water are not completely understood. In Maine (USA), peatlands began forming about 10,000 years ago following the retreat of the ice sheets and glaciers at the end of the last ice age. They formed in depressions, often starting as lakes, within the landscape carved by glaciers and draped with sediments. These landforms lie buried beneath peatlands but may play a key role in regulating both the hydrology and release of methane gasses into the atmosphere. This project will use subsurface geophysical sensing methods to image this hidden post-glacial landscape in order to understand how it regulates groundwater flow in peatlands and where/when methane emissions occur. Hydrological observations and computer simulations of deeper groundwater and peat porewater flow will be compared to direct measurements of methane gas emissions from peatlands in the search for evidence that peatland hydrology and carbon cycling are regulated by this hidden landscape. In addition to advancing scientific understanding of the link between hydrologic processes in the deep critical zone of northern peatlands and carbon fluxes to the atmosphere, this project will bring unique elements of benefit to society. It will contribute to the development of a diverse workforce with a strong engagement of underrepresented students, support graduate and undergraduate students, and build collaborative interactions with the forest management industry.The goal of this project is to evaluate how the deep critical zone regulates coupled water-carbon processes across peatland landforms at a regional scale. Geophysical imaging, hydrological observations and computational modeling of groundwater flow and transport will be performed across 10 peatlands to explore three hypotheses (abbreviated here): [1] Unidentified esker (glacially derived sand and gravel) ridges lie buried beneath numerous Maine peatlands; [2] These (or similar) permeable deposits hydraulically connect peatland pore waters to the underlying groundwater aquifer; and [3] This hydraulic connection results in hotspots of methane release centered on buried permeable mineral deposits. Ground penetrating radar and frequency domain electromagnetics will be used to illuminate the geological framework beneath these peatlands and to locate buried esker deposits. Coring and permeability tests will constrain flow and transport models calibrated on [1] hydraulic heads recorded with pressure transducers connected to data loggers, and [2] specific conductance measured in water samples. Ebullition fluxes will be estimated at predicted methane hotspots using low maintenance methods (gas traps, moisture probe arrays). Underrepresented minority students from urban areas will engage in wilderness research experiences focusing on all aspects of data acquisition. A collaboration with a forestry management company secures access to privately owned peatlands for research. Informational brochures describing peatland processes investigated in this project will be developed targeting the local community and the State of Maine.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

北方泥炭地是在美国北方发现的一种独特类型的湿地，也是高纬度地区的主要地貌，包括加拿大、北方斯堪的纳维亚半岛和俄罗斯。工业发展导致一些泥炭地被排干或焚烧，以促进农业、建筑或用作燃料。今天，泥炭地被认为是独特的生态系统，支持在其他地方找不到的各种植物。此外，它们是全球碳循环的重要组成部分，将二氧化碳捕获在有机物质中，并储存了土壤中发现的约33%的总碳。泥炭地释放出的部分碳以甲烷的形式进入大气，甲烷是一种强有力的温室气体。虽然泥炭地的生态学已经得到了很好的研究，但对泥炭地发育的地质控制和泥炭地水的渗透模式还没有完全了解。在缅因州（美国），泥炭地开始形成约10,000年前，随着冰盖和冰川的退缩，在最后一个冰河时代结束。它们形成于洼地，通常始于湖泊，在冰川雕刻的景观中，覆盖着沉积物。这些地貌埋藏在泥炭地之下，但可能在调节水文和甲烷气体释放到大气中方面发挥关键作用。该项目将使用地下地球物理传感方法对这一隐藏的冰后期景观进行成像，以了解它如何调节泥炭地的地下水流以及甲烷排放发生的地点/时间。水文观测和更深的地下水和泥炭孔隙水流的计算机模拟将进行比较，从泥炭地的甲烷气体排放量的直接测量，在寻找证据，泥炭地水文和碳循环调节这一隐藏的景观。除了促进对北方泥炭地深层临界区水文过程与大气碳通量之间联系的科学认识外，该项目还将为社会带来独特的惠益因素。它将有助于发展一支多元化的劳动力队伍，让代表性不足的学生积极参与，支持研究生和本科生，并与森林管理行业建立协作互动。该项目的目标是评估深层关键区如何在区域范围内调节泥炭地地貌的耦合水碳过程。将在10个泥炭地进行地球物理成像、水文观测和地下水流动和运输的计算建模，以探索三个假设（此处略）：[1]未识别的esker（冰川形成的沙子和砾石）山脊埋藏在众多的缅因州泥炭地之下; [2]（或类似）渗透性沉积物在水力上将泥炭地孔隙沃茨与下面的地下含水层连接起来;[3]这种水力联系导致甲烷释放的热点集中在埋藏的渗透性矿床上。探地雷达和频域电磁学将用于照亮这些泥炭地下的地质框架，并定位埋藏的埃斯克矿床。取芯和渗透率测试将限制在[1]连接到数据记录器的压力传感器记录的水压头上校准的流动和运输模型，以及[2]在水样中测量的电导率。将使用低维护方法（气体收集器、湿度探针阵列）在预测的甲烷热点估计沸腾通量。来自城市地区的代表性不足的少数民族学生将从事荒野研究经验，重点是数据采集的各个方面。与一家林业管理公司的合作确保了对私人拥有的泥炭地的研究。将针对当地社区和缅因州开发描述本项目中调查的泥炭地过程的信息手册。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。