Collaborative Research: Experimental Investigation of Morphodynamic Coupling between River Deltas and Marshes

河流三角洲和沼泽河三角洲之间地貌动力学耦合的实验研究作为数亿人的人口中心和基础设施枢纽，对社会具有重要意义。大多数河流三角洲拥有广阔的沼泽，这些沼泽是生物多样性的热点、生产性渔业、有效的风暴防护，以及捕获和储存大量碳。作为海平面上升和沉积物输入的函数，河流三角洲和沼泽的生长和崩溃过程是孤立的，这是众所周知的。然而，对于沼泽和三角洲是如何相互作用的，人们基本上缺乏了解。沼泽和三角洲动力之间的反馈是否从根本上影响了两者的行为？研究人员将根据受控的环境条件建立实验室规模的三角洲，该三角洲将与新开发的沼泽代理相互作用，该代理以较小的规模模拟关键的沼泽属性。这些实验将有助于揭示河流三角洲和沼泽在简单条件下如何在一百到一千年的时间尺度上相互作用，并提供对目前正在影响密西西比河和其他全球河流三角洲的土地流失和沉降问题的洞察。该项目将在路易斯安那州的K-12教室播放实验，培训阿肯色大学和杜兰大学的不同研究人员，并将结果转化为通过社交媒体平台设计的文章供公众消费。研究人员将使用物理实验室实验来研究河流三角洲和沼泽是如何相互作用的，其中将结合一种新型的沼泽代理。这一沼泽替代物将被添加到三角洲实验中，遵循基于规则的沉积模型，该模型基于不断演变的沉积物的局部高程。这将第一次让他们记录三角洲的内部动力是如何被覆盖了许多三角洲平原的大片沼泽所增强的。通过与以前在没有沼泽的情况下演化的实验进行比较，它们将分离出地表动力学、压实沉降模式和沼泽-三角洲耦合的地层产物。这项研究中发展的定量理论将有助于预测沼泽和三角洲在未来几十年的可持续性，并提高解释其地层以记录古环境的能力。研究将由一个不同的团队进行(在性别、种族和职业阶段)，包括本科生和研究生，并扩展到K-12学生。该项目由地貌学和土地利用动态计划和既定的激励竞争研究计划(EPSCoR)共同资助。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。

Experimental Investigation of Morphodynamic Coupling between River Deltas and MarshesRiver deltas are important to society as population centers and infrastructure hubs for hundreds of millions of people. Most river deltas host vast marshes that are biodiversity hotspots, productive fisheries, effective storm protection, and that capture and store significant amounts of carbon. The processes by which river deltas and marshes grow and collapse as a function of rising sea level and sediment input are well known in isolation. However, there is a fundamental lack of understanding of how marshes and deltas interact. Do feedbacks between marsh and delta dynamics fundamentally influence the behavior of both? The researchers will build laboratory scale deltas subject to controlled environmental conditions that will interact with a newly developed marsh proxy that mimics key marsh properties at a reduced scale. These experiments will help reveal how river deltas and marshes interact over hundred to thousand year timescales under simple conditions, and provide insight into the land loss and subsidence problems that are currently affecting the Mississippi and other global river deltas. The project will broadcast experiments into K-12 classrooms in Louisiana, train a diverse group of researchers at University of Arkansas and Tulane University, and translate results into articles designed for public consumption through social media platforms.The researchers will study how river deltas and marshes interact using physical laboratory experiments that will incorporate a novel marsh proxy. This marsh proxy will be added to deltaic experiments following a rule-based model of sedimentation based on the local elevation of the evolving deposit. For the first time, this will allow them to document how the internal dynamics of deltas are augmented by marshes that cover vast swaths of many delta plains. Through comparison to prior experiments that evolved in the absence of marshes, they will isolate surface dynamics, compactional subsidence patterns, and stratigraphic products of marsh-delta coupling. Quantitative theory developed in this study will aid prediction of marsh and deltas sustainability in the coming decades and enhance ability to interpret their strata for paleo-environmental records. Research will be conducted by a diverse team (in gender, ethnicity, and career stage) including undergraduate and graduate students, and outreach to K-12 students. This project is jointly funded by the Geomorphology and Land-Use Dynamics Program 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.