Collaborative Research: A Multiple Tracer Approach to Evaluate Groundwater Discharge into River Dominated Coastal Waters

在这个项目中，东卡罗莱纳大学、杜兰大学和迈阿密大学的研究人员将尝试一种综合的方法来定量估计地下水排放和相关的溶解成分到大陆架沃茨。 最近的一些研究表明，地下水向沿海地区的迁移可能是许多海洋近岸沃茨的地球化学、营养和碳收支的一个重要过程。该项目将解决的方式，我们可以评估地下水和地表水之间的相互作用的一个主要的河流为主的边缘，密西西比河三角洲。研究小组将开发和应用一种新的多重示踪剂的方法，涉及使用222 Rn/226 Ra，4 He/3 He/氚，和短寿命的镭同位素作为地下水流动的天然示踪剂，以检查邻近密西西比河的边缘。在整个项目期间，将从路易斯安那州海岸附近的陆基地下水威尔斯井、通过卡斯滕岩心采集的深层孔隙水以及从密西西比河下游和邻近大陆架采集的地表沃茨中采集水样。为了评估地下水输入和地表水示踪剂库存之间的联系，我们团队将构建这些天然示踪剂的所有可能输入和输出的平衡。这项基于实地的研究将用于开发和约束研究区域的数值水文模型。模型结果将与从地球化学模型中获得的地下水流量估计值进行比较。

ABSTRACTOCE-0220215 / OCE-0221161 / OCE-0217164In this project researchers at East Carolina University, Tulane University, and the University of Miami will attempt to a comprehensive approach to allow a quantitative estimate of groundwater discharge and associated dissolved constituents to continental shelf waters. A number of recent studies have shown that he transport of groundwater into coastal zones may be a significant process in the geochemical, nutrient, and carbon budgets of many marine nearshore waters. This project will address the manner in which we may evaluate interactions between groundwater and surface water a major river-dominated margin, the Mississippi River delta.The research team will develop and apply a novel multiple-tracer approach involving the use of 222Rn/ 226Ra, 4He/3He/tritium, and short-lived radium isotopes as natural tracers of groundwater flow to examine the margin adjacent to the Mississippi River. Water samples will be collected from land-based groundwater wells near the Louisiana coast, deep porewaters via Kasten core, and surface waters from the lower Mississippi and adjacent continental shelf throughout the project. To evaluate the connection between groundwater inputs and surface water tracer inventories, we team will construct a balance of all possible inputs and outputs of these natural tracers.. This field-based research will be used to develop and constrain a numerical hydrologic model for the study area. Model results will be compared to estimates of groundwater flow obtained from geochemical modeling.