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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？

基本信息

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

项目摘要

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，是包括加拿大、斯堪的纳维亚北部和俄罗斯在内的高纬度地区的主要地貌。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，支持着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大约33%的总碳。泥炭地将其中的一些碳以甲烷的形式释放到大气中，甲烷是一种强有力的温室气体。虽然泥炭地的生态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流模式还没有完全了解。在美国缅因州，大约10,000年前，随着冰盖和冰川在上一个冰河时代末期的消退，泥炭地开始形成。它们形成于凹陷中，通常从湖泊开始，在冰川雕刻的地形中，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向大气中释放甲烷气体方面发挥关键作用。该项目将使用地下地球物理传感方法对这一隐藏的冰川后景观进行成像，以了解它如何调节泥炭地的地下水流动以及甲烷排放的地点/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一隐藏景观调控的证据。除了促进对北部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理解外，该项目还将为社会带来独特的有益因素。该项目的目标是评估深层临界区如何在区域范围内调节泥炭地地貌的水碳耦合过程。该项目的目标是评估深层临界区如何调节泥炭地地貌的水-碳耦合过程。将对10个泥炭地的地下水流动和运移进行地球物理成像、水文观测和计算模拟，以探索三种假说(此处略有)：[1]埋藏在许多缅因州泥炭地之下的不明身份的ESCER(冰川衍生的砂砾)脊；[2]这些(或类似)可渗透沉积通过水力将泥炭地的孔隙水与地下地下含水层连接起来；[3]这种水力连接导致以埋藏的可渗透矿藏为中心的甲烷释放热点。探地雷达和频域电磁学将被用来照亮这些泥炭地下面的地质框架，并定位埋藏的埃斯克矿藏。取心和渗透率测试将约束在[1]用连接到数据记录仪的压力传感器记录的水力压头上校准的流动和输送模型，以及[2]在水样中测量的比电导。将使用低维护方法(气体捕集器、湿度探头阵列)在预测的甲烷热点估计沸腾通量。来自城市地区的未被充分代表的少数民族学生将从事野外研究体验，重点放在数据获取的各个方面。与一家林业管理公司的合作确保了进入私人拥有的泥炭地进行研究的机会。将针对当地社区和缅因州编制描述本项目调查的泥炭地过程的宣传手册。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。