Tracing Submarine Groundwater Discharge into the Ocean

追踪海底地下水排放到海洋中

• 批准号: 9101797
• 负责人: William Burnett
• 金额: $ 36.17万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-10-15 至 1995-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9101797&HistoricalAwards=false
• 关键词: Tracing; Submarine; Groundwater; Discharge; into

Submarine springs and seeps discharge a substantial but not precisely defined quantity of water into the ocean. Recent estimates suggest that the magnitude of this discharge, driven by gravitational and convective forces, may be globally significant. Discharged fluids may consist of fresh water, connate waters, brines derived from evaporite deposits, or recirculated seawater. Because the composition of submarine hydrologic discharge may be markedly different than seawater, this process is capable of contributing significantly to the marine geochemical cycling of many elements. The proposed research will determine the potential of using water column standing crops of the tracers 222Rn, 226Ra and CH4, constituents greatly enriched in groundwater relative to seawater, for the purpose of locating and assessing submarine groundwater discharge to the ocean. A detailed geochemical mass balance will be constructed for the single best tracer, 222Rn, within a relatively small area on the continental shelf of northwest Florida, an area where we expect to find appreciable submarine discharge. Groundwater tracer concentrations and fluxes will be measured, both in the form of discrete springs and as disseminated seeps. Benthic fluxes and other processes, such as advection and air-sea exchange, which contribute to changes in the water column standing crop will be evaluated. These measurements will be modeled to evaluate the prospects of developing a simple tracer-based technique for determining the magnitude of groundwater discharge to the ocean applicable to other areas.

海底弹簧和渗入将大量但未确切定义的水排放到海洋中。 最近的估计表明，由重力和对流力驱动的该排放量可能具有全球意义。 排放的液体可能包括淡水，饲养水，源自蒸发矿床的盐水或循环海水。 由于海底水文排放的组成可能与海水明显不同，因此该过程能够显着促进许多元素的海洋地球化学循环。 拟议的研究将确定使用示踪剂2222222226RA和CH4的水柱驻地作物的潜力，该组成部分相对于海水大大富集了地下水，目的是将海底地下水排放到海洋中。 将在佛罗里达州西北部大陆架的相对较小的区域内为单一最佳示踪剂（222RN）建造详细的地球化学质量平衡，我们希望在该区域找到可观的海底排放。 地下水示踪剂的浓度和通量都将以离散弹簧的形式和分布的渗透来测量。 将评估底栖通量和其他过程，例如对流和空气交换，这些过程将有助于水柱常规作物的变化。 这些测量结果将进行建模，以评估开发基于简单的示踪技术的前景，以确定适用于其他地区的海洋的地下水排放的大小。