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Examining submarine ground-water discharge into simpson bay, alaska with electrical resistivity and radon

Abstract:

Estimates of submarine ground-water discharge (SGD) have remained one of the most elusive components of a coastal water and constituent budget. Nonetheless, environmental impacts of SGD are often widespread, and have been tied to coastal eutrophication, algal blooms, and near-shore bacterial transport. New geochemical and geophysical techniques have recently been developed to better quantify rates and scales of SGD. Simpson Bay, in eastern Prince William Sound, Alaska, was chosen as a SGD endmember field site where hydrogeologic conditions should maximize coastal ground-water discharge. In Simpson Bay, the tidal range is large ( & gt; 5 m), there is significant recharge (annual precipitation can exceed 400 cm), and the ubiquitous glacially-derived coastal sediment can contain hydrologically transmissive units. The natural geochemical tracer 222Rn was used to quantify total (saline + fresh water component) SGD at one site within the bay, while simultaneous, multi-electrode, land-based resistivity surveys were used to examine the dynamics of the fresh water /salt water interface and SGD mixing scales and patterns.