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

在这个项目中，东卡罗来纳大学、杜兰大学和迈阿密大学的研究人员将尝试一种全面的方法，以实现对大陆架水域地下水排放和相关溶解成分的定量估计。最近的一些研究表明，地下水向海岸带的输送可能是许多海洋近岸水域的地球化学、营养和碳收支中的一个重要过程。这个项目将解决我们可以评估地下水和地表水之间相互作用的方式，一个主要的河流控制的边缘，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方法，涉及使用222Rn/226Ra，4He/3He/氚，和短寿命的镭同位素作为地下水流动的天然示踪剂，以检查密西西比河邻近的边缘。整个项目将从路易斯安那州海岸附近的陆上地下水井、通过卡斯滕核的深层孔隙水以及密西西比州下游和邻近大陆架的地表水中采集水样。为了评估地下水输入和地表水示踪剂库存之间的联系，我们团队将建立这些天然示踪剂所有可能的输入和输出的平衡。这项实地研究将用于开发和约束研究区的数值水文模型。模型结果将与通过地化模拟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.