Hydrological Control of Particle Entrainment and Nitrogen Cycling in Beach Aquifer Mixing and Reaction Zones

海滩含水层混合和反应区颗粒夹带和氮循环的水文控制

• 批准号: 1246554
• 负责人: Holly Michael
• 金额: $ 51.05万
• 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: 2013
• 资助国家: 美国
• 起止时间: 2013-02-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1246554&HistoricalAwards=false
• 关键词: Hydrological; Control; Particle; Entrainment; Nitrogen

Sandy beaches are valuable recreational and economic resources in coastal regions, and also provide important but often underappreciated biogeochemical and ecological services. Beach aquifers are important hydrological interfaces between land and sea through which terrestrial contaminants dissolved in groundwater pass prior to reaching the ocean. Within these aquifers are reactive zones that can moderate chemical fluxes; understanding of the processes that control such reactivity is essential for predicting the conditions that promote biogeochemical and ecological benefits. The objectives of this work are to gain new understanding of the role that physical processes of fluid flow and organic particle transport have in maintaining the reactivity of beach aquifers and to assess the potential impact of anthropogenic and natural changes on contaminant loads to the ocean. This field, laboratory, and modeling study will (1) assess the driving mechanisms, patterns, and rates of fluid flow and associated organic particle incorporation into sandy beaches as a result of tide and wave action, (2) characterize the amount, nature, and reactivity of organic matter in beach sediments and porewater, and (3) determine spatial and temporal variations in the concentrations and fluxes of nutrients to and through the beach resulting from flow, mixing, and respiration of particulate and dissolved organic substrates. The proposed work will fill a gap in knowledge that will allow inference of potential reactivity from the physical characteristics of beach aquifer systems. The predictive capacity developed from the scientific results can be transferred to other systems and processes (such as oil spill remediation) and will enable prediction of potential effects of human influences and longer-term changes in sea level and climate on the ecological services of beach aquifer reactors. The research will aid beach managers in assessing the ecological value of sandy beaches and the need for management activities to maintain ecosystem services. The work may also help managers concerned with coastal eutrophication make more accurate estimates of the nutrient loads to estuarine and coastal waters based on easily assessed physical characteristics of shorelines. The research will have educational impacts, providing interdisciplinary training for graduate and undergraduate students interested in increasingly inter- and multi-disciplinary environmental issues. The field sites will be developed into hands-on training sites for hydrogeology courses at the University of Delaware (UD) and for the UD TIDE Camp for high school students.

沙滩是沿海地区宝贵的娱乐和经济资源，也提供重要但往往不被重视的生物地球化学和生态服务。海滩含水层是陆地和海洋之间重要的水文界面，溶解在地下水中的陆地污染物在到达海洋之前通过这里。在这些含水层中存在可以调节化学通量的反应带；了解控制这种反应性的过程对于预测促进生物地球化学和生态效益的条件至关重要。这项工作的目标是对流体流动和有机颗粒输送的物理过程在维持海滩含水层反应性方面的作用有新的认识，并评估人为和自然变化对海洋污染物负荷的潜在影响。这一实地、实验室和模型研究将(1)评估潮汐和波浪作用导致的流体流动和相关有机颗粒进入沙滩的驱动机制、模式和速率，(2)表征海滩沉积物和孔隙水中有机物的数量、性质和反应性，以及(3)确定由于流动、混合、微粒和溶解的有机基质的呼吸作用。拟议的工作将填补知识上的空白，这将允许从海滩含水层系统的物理特征推断潜在的反应性。从科学成果中发展出来的预测能力可以转移到其他系统和过程中（例如漏油补救），并将能够预测人类影响和海平面和气候的较长期变化对海滩含水层反应堆的生态服务的潜在影响。这项研究将协助海滩管理人员评估沙滩的生态价值，以及为维持生态系统服务而进行管理活动的必要性。这项工作还可以帮助有关沿海富营养化的管理人员根据容易评估的海岸线物理特征，对河口和沿海水域的营养负荷作出更准确的估计。这项研究将对教育产生影响，为研究生和本科生提供跨学科的培训，这些学生对越来越多的跨学科和多学科的环境问题感兴趣。这些实地地点将被开发成特拉华大学水文地质学课程的实践训练地点，以及特拉华大学面向高中生的潮汐夏令营。