Tracing Submarine Groundwater Discharge into the Ocean

海底泉水和渗漏排出大量的 精确定义的水量。 最近 估计表明，这种排放的规模， 在重力和对流的作用下， 显著 排出的流体可能包括淡水， 原生沃茨、蒸发岩沉积物产生的卤水，或 循环海水 因为潜艇的组成 水文排放可能明显不同于海水， 这一过程能够大大有助于 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~（222）Rn、~（226）Ra和 CH 4，在地下水中相对于 海水，用于定位和评估潜艇 地下水排入海洋。 详细的地球化学 将为单个最佳示踪剂构建质量平衡， 222 Rn，在大陆架上相对较小的区域内 位于佛罗里达西北部，我们希望在那里找到 明显的潜艇放电。 地下水示踪剂 浓度和通量将被测量，无论是在形式 分散的泉水和分散的渗漏。 底栖通量和 其他过程，如平流和海气交换， 有助于改变水柱现存作物将是 评估。 将对这些测量结果进行建模，以评估 开发一种简单的基于示踪剂的技术， 确定地下水排入海洋的数量 适用于其他领域。

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.