We investigated the role submarine groundwater discharge (SGD) plays in the delivery of nutrients and copper to the Elizabeth River (Virginia) estuary, a major subestuary of lower Chesapeake Bay. Using an approach based on radium isotopes, we concluded that two distinct sources of groundwater were equally impacting the estuary: a surface (marsh) aquifer and deep aquifer source each with a unique Ra-228/Ra-226 activity ratio. Considering each of these sources, we calculated an SGD flux of 1 x 10(6) m(3) d(-1) (+/-10%), which represented similar to6% of the SGD flux for the entire Chesapeake Bay and similar to5% of the James River, a major source of freshwater to lower Chesapeake Bay. SGD-derived dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) fluxes averaged 4.5 (+/-4.6) and 0.16 (+/-0.17) mmol m(-2) d(-1), respectively, and compared well with area-normalized fluxes to Chesapeake Bay. In contrast, SGD-derived Cu input of 730 (+/-390) kg yr(-1) was a relatively small source of Cu (similar to3%) to the Elizabeth estuary given that surface water inputs, such as antifouling paints associated with naval operations, are a major component of the Cu budget for this system. These findings were in general agreement with prior studies of SGD for this region.
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