THE IMPACT OF SPRING REVERSALS ON CARBONATE MINERAL DISSOLUTION AND TRACE METAL MOBILITY IN PHREATIC CAVE SYSTEMS

摘要

Surface water and groundwater exchange is extensive in karst aquifers and thus can affect the redox state of karst waters. Flooding causes rivers to flow into spring vents that normally discharge from the Floridan aquifer system, thereby introducing oxygen and dissolved organic carbon (DOC) into the typically suboxic environment. DOC drives biogeochemical reactions that result in increased carbonate mineral dissolution and the reductive dissolution of Fe and Mn oxides and associated trace metals. The control these reactions have on ground water chemistry depends on the flood water chemistry, as well as the hydraulic conditions that determine the duration that river water remains in the groundwater system.