Collaborative Research: Hydrogeophysical monitoring and modeling of heterogeneity in salinization processes across the marsh-upland transition

合作研究：沼泽-高地转变过程中盐化过程异质性的水文地球物理监测和建模

• 批准号: 2316493
• 负责人: Holly Michael
• 金额: $ 25.58万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2316493&HistoricalAwards=false
• 关键词: Collaborative; Research; Hydrogeophysical; monitoring; modeling

Rising sea levels driven by climate change threaten to transform coastal landscapes with profound, global economic implications. Within the coastal zone, increased flooding of soils with saline water disrupts the natural cycling of nutrients and carbon between soils, the atmosphere and the ocean. Coastal marshes are an important sink of terrestrial carbon, and carbon accumulation rates in coastal marshes exceed those of temperate forests. Whereas gradual sea-level rise results in slow, lateral inland movement of saline groundwater, storms and large tides cause rapid inundation of soils with saltwater, driving vertical transport of salt into soils. The ecological consequences of these processes are visible to the naked eye, particularly across the transition between coastal marshes and forested uplands, where increasing soil water salinity results in tree mortality and the formation of ‘ghost forests’. However, the patterns of salinity change beneath the subsurface in soils and groundwater are unclear, particularly as numerous positive and negative feedback mechanisms may exist. For example, the death of individual trees may locally enhance vertical transport of salt if dead roots and surrounding soil serve as preferential pathways for the transport of saline water. Variations in soil texture (e.g., grain size) across the marsh-upland transition may also result in variability in rates of salinization both during short-term storm events and in response to gradual sea-level rise.This project will apply electrical geophysical imaging technologies and hydrological models of saltwater transport to improve understanding of the role of subsurface heterogeneity (both geology and vegetation induced) in regulating gradual and rapid (storm surge) hydrological processes across multiple marsh-upland transition zones. Electrical geophysical imaging methods provide spatially continuous, non-invasive information of variations in salinity. In this project, these methods will be deployed to monitor the evolution of salinity changes in response to major storm events. The work will [1] produce data and simulations to improve conceptual models for salinization resulting from storm events by incorporating the role of subsurface heterogeneity; [2] develop strategies to improve the predictive capabilities of hydrological models of saltwater transport by incorporating spatially and temporally rich geophysical observations; [3] promote awareness of geophysical imaging technologies for investigating coastal landscapes within a broad community of interdisciplinary scientists; [4] engage a diverse body of students and early career scientists in workshops studying the marsh-upland transition. This project is jointly funded by Hydrologic Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).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.

气候变化导致的海平面上升可能会改变沿海景观，对全球经济产生深远影响。在沿海地区，含盐水的土壤泛滥加剧，破坏了土壤、大气和海洋之间营养物质和碳的自然循环。沿海沼泽是陆地碳的重要汇，其碳积累速率超过温带森林。海平面的逐渐上升导致含盐地下水缓慢的横向内陆运动，而风暴和大潮汐导致海水迅速淹没土壤，推动盐向土壤的垂直运输。这些过程的生态后果是肉眼可见的，特别是在沿海沼泽和森林高地之间的过渡地区，土壤水盐度的增加导致树木死亡和“幽灵森林”的形成。然而，地下土壤和地下水中盐度变化的模式尚不清楚，特别是因为可能存在许多正反馈和负反馈机制。例如，如果死根和周围土壤是盐水运输的优先通道，那么单株树木的死亡可能会局部增强盐的垂直运输。在沼泽-高地过渡期间，土壤质地（例如，颗粒大小）的变化也可能导致短期风暴事件期间和海平面逐渐上升时盐碱化率的变化。该项目将应用电地球物理成像技术和咸水运输的水文模型，以提高对地下异质性（地质和植被诱导）在调节多个沼泽-高地过渡带渐进和快速（风暴潮）水文过程中的作用的理解。电地球物理成像方法提供了空间连续的、非侵入性的盐度变化信息。在本项目中，这些方法将用于监测主要风暴事件下盐度变化的演变。这项工作将产生数据和模拟，通过纳入地下非均匀性的作用，改进风暴事件导致的盐渍化的概念模型；[2]制定战略，通过纳入空间和时间上丰富的地球物理观测，提高咸水输送水文模型的预测能力；[3]在广泛的跨学科科学家群体中促进对研究沿海景观的地球物理成像技术的认识；b[4]吸引了各种各样的学生和早期职业科学家参加研讨会，研究沼泽-高地过渡。该项目由水文科学和促进竞争研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，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。