posted on 2015-10-20, 00:00authored byNatasha T. Dimova, Adina Paytan, John D. Kessler, Katy J. Sparrow, Fenix Garcia-Tigreros Kodovska, Alanna L. Lecher, Joseph Murray, Slawomir M. Tulaczyk
To better understand groundwater–surface
water dynamics
in high latitude areas, we conducted a field study at three sites
in Alaska with varying permafrost coverage. The natural groundwater
tracer (222Rn, radon) was used to evaluate groundwater
discharge, and electrical resistivity tomography (ERT) was used to
examine subsurface mixing dynamics. Different controls govern groundwater
discharge at these sites. In areas with sporadic permafrost (Kasitsna
Bay), the major driver of submarine groundwater discharge is tidal
pumping, due to the large tidal oscillations, whereas at Point Barrow,
a site with continuous permafrost and small tidal amplitudes, fluxes
are mostly affected by seasonal permafrost thawing. Extended areas
of low resistivity in the subsurface alongshore combined with high
radon in surface water suggests that groundwater–surface water
interactions might enhance heat transport into deeper permafrost layers
promoting permafrost thawing, thereby enhancing groundwater discharge.