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: 2051907
• 负责人: Xavier Comas
• 金额: $ 21.9万
• 依托单位: Florida Atlantic University
• 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=2051907&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.

北部泥炭地是美国北部发现的一种独特的湿地类型，也是高纬度地区的主要地貌，包括加拿大、斯堪的纳维亚半岛北部和俄罗斯。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。如今，泥炭地被认为是独特的生态系统，支持着其他地方没有的多种植物。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中，并储存了土壤中约 33% 的碳。泥炭地将部分碳以甲烷（一种强效温室气体）的形式释放到大气中。尽管对泥炭地的生态学进行了深入研究，但对泥炭地发展的地质控制和泥炭地水的渗滤模式尚不完全了解。在美国缅因州，随着上一个冰河时代末期冰盖和冰川的退缩，泥炭地于大约 10,000 年前开始形成。它们形成于洼地中，通常以湖泊开始，在冰川雕刻和覆盖着沉积物的景观中。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向大气中的释放方面发挥着关键作用。该项目将使用地下地球物理传感方法对这一隐藏的冰河后景观进行成像，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。对深层地下水和泥炭孔隙水流的水文观测和计算机模拟将与泥炭地甲烷气体排放的直接测量进行比较，以寻找泥炭地水文和碳循环受这种隐藏景观调节的证据。除了增进对北部泥炭地深层关键区域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效益。它将有助于发展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域如何调节耦合水-区域范围内泥炭地地貌的碳过程。将在 10 个泥炭地中进行地球物理成像、水文观测以及地下水流和运输的计算建模，以探索三个假设（此处缩写）： [1] 不明的埃斯克（冰川产生的沙子和砾石）山脊埋藏在许多缅因州泥炭地之下； [2] 这些（或类似的）渗透性沉积物通过水力将泥炭地孔隙水与下面的地下水含水层连接起来； [3] 这种水力连接导致甲烷释放热点集中在埋藏的可渗透矿藏上。探地雷达和频域电磁学将用于照亮这些泥炭地下方的地质框架并定位埋藏的埃斯克沉积物。取芯和渗透性测试将限制在[1]使用连接到数据记录器的压力传感器记录的水头和[2]在水样中测量的比电导度上校准的流量和传输模型。将使用低维护方法（气体捕集器、湿度探针阵列）在预测的甲烷热点处估算沸腾通量。来自城市地区的少数族裔学生将参与荒野研究，重点关注数据采集的各个方面。与林业管理公司合作，确保能够使用私人拥有的泥炭地进行研究。将针对当地社区和缅因州开发描述本项目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智力优点和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

The Role of the Critical Zone Structure on the Hydrology and Pool Patterning of Boreal Peatlands

关键带结构对北方泥炭地水文和水池格局的作用

• 发表时间: 2021-10
• 期刊: FastTIMES
• 作者: Comas, X;Slater, L.;Reeve, A.
• 通讯作者: Reeve, A.