CAREER: Quantitative Education and Analysis toward Integrating Scales of Water Exchange between Land and Sea

职业生涯：陆地和海洋之间水交换综合尺度的定量教育和分析。含水层和海洋之间的水和化学通量对海岸的生物，地质和地球化学过程至关重要。流入海洋的地下水可造成藻类大量繁殖，改变海洋化学性质，海水渗入陆地可造成含水层盐碱化，改变地下水的溶质和矿物组成。在量化含水层-海洋通量方面的一个独特挑战是，驱动交换的机制在空间和时间尺度上的范围很广。强迫发生在波浪、季节和冰川周期的时间尺度上，相应的空间尺度从涟漪到大陆架。整合交换的尺度对于理解和预测这些通量在地质历史和未来海平面变化中的影响至关重要。这项工作的长期愿景是通过将地球科学和数学联系起来的研究和教育，增进对连接含水层和海洋的物理过程的了解。该研究项目将探讨地质异质性（水文地质特性的空间变化）对大陆架尺度的海洋-含水层水交换过程的影响。地质统计学建模和变密度地下水流和溶质运移模拟将用于了解非均匀性几何形状对以下方面的影响：（1）海底水交换的空间模式，（2）密度驱动的地下盐水循环，以及（3）海水侵入含水层，这些过程对水资源、沿海生态系统和海洋化学非常重要。两个系统，显示非常不同的几何形状和地质特征的连接将被建模：孟加拉三角洲和夏威夷群岛。这项研究将与一项旨在将数学纳入地球科学课程的教育计划相联系。将通过与特拉华州自然协会和Kamehmeha学校合作，为特拉华州和夏威夷的高中生制定和实施地下水-地表水交流活动，并将在特拉华州大学开设新的和修改后的本科生和研究生课程，纳入研究的各个方面。该项目将创造关于含水层与海洋之间产生水交换的物理过程及其产生的水和化学通量的新知识。这项工作将填补一个空白，即了解含水层的地质结构在将这些物理过程转化为大陆架范围内地下水盐碱化（从海洋流向陆地）和地下水流向海洋（从陆地流向海洋）方面的作用。这项工作将对教育、水资源管理和生态保护产生影响。科学成果将为水资源管理人员提供改进管理模式和风险评估的基础。所获得的见解将改进未来实地研究的设计，加强保护脆弱的沿海生态系统的努力，并可能对海上钻井活动和风电场选址产生影响。改进对陆地-海洋通量的预测也将使我们能够更好地预测和适应气候变化对沿海水资源和生态系统的潜在影响。

CAREER: Quantitative Education and Analysis toward Integrating Scales of Water Exchange between Land and SeaHolly A. MichaelUniversity of DelawareWater and chemical fluxes between aquifers and the ocean are critically important to biological, geological, and geochemical processes at the coast. Groundwater inputs to the sea can cause algal blooms and modify ocean chemistry, and seawater infiltration to land causes aquifer salinization and alters solute and mineral composition of the subsurface. A unique challenge in quantifying aquifer-ocean fluxes is the wide range of spatial and temporal scales over which the mechanisms that drive exchange operate. Forcing occurs on timescales of waves, seasons, and glacial cycles, with corresponding spatial scales from ripples to continental shelves. Integrating the scales of exchange is essential for understanding and predicting the impacts of these fluxes through geologic history and as sea level changes in the future. The long-term vision of this work is to improve understanding of physical processes that connect aquifers and the sea through research and education that link geosciences and mathematics. The research project will explore the influence of geologic heterogeneity (spatial variations in hydrogeologic properties) on continental shelf-scale ocean-aquifer water exchange processes. Geostatistical modeling and variable-density groundwater flow and solute transport simulation will be used to understand the influence of the geometry of heterogeneity on (1) spatial patterns of seafloor water exchange, (2) density-driven saltwater circulation in the subsurface, and (3) seawater intrusion into aquifers, processes important for water resources, coastal ecosystems, and ocean chemistry. Two systems that display very different geometry and connectivity of geologic features will be modeled: the Bengal Delta and the Hawaiian Islands. This research will be linked to an educational program designed to integrate mathematics into geoscience curricula. A groundwater-surface water exchange activity for high school students in Delaware and Hawaii will be developed and implemented through cooperation with the Delaware Nature Society and Kamehmeha Schools, and new and modified undergraduate and graduate courses that incorporate aspects of the research will be offered at the University of Delaware. This project will create new knowledge of the physical processes that generate water exchange between aquifers and the ocean and the water and chemical fluxes that they produce. The work will fill a gap in understanding of the role of the geologic structure of an aquifer in translating these physical processes into groundwater salinization (flux from sea to land) and groundwater flow to the ocean (flux from land to sea) on the scale of the continental shelf. The work will have impacts on education, water resource management, and ecological preservation. Scientific results will provide water resources managers with a basis for improving management models and risk assessments. Insights gained will improve design of future field studies, enhance efforts to protect fragile coastal ecosystems, and may have implications for offshore drilling activities and siting of wind farms. Improved prediction of land-sea fluxes will also allow us to better anticipate and adapt to potential effects of climate change on coastal water resources and ecosystems.