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Full-Text Articles in Physical Sciences and Mathematics

Mobility Of Escherichia Coli Within Karst Terrains, Kentucky, Usa, Ashley M. Bandy Jan 2016

Mobility Of Escherichia Coli Within Karst Terrains, Kentucky, Usa, Ashley M. Bandy

Theses and Dissertations--Earth and Environmental Sciences

Bacterial contamination of karst aquifers is a concern as water quality across the globe deteriorates in the face of decreasing water security. This study examined the transport and attenuation of two non-virulent isolates of Escherichia coli in relation to traditional groundwater tracers such as rhodamine WT dye and latex microspheres in two karst regions in Kentucky. Differential movement between the four tracers was observed in both epikarst and karst aquifer traces, with differences in behavior dependent on flow conditions. Attenuation was greater for the bacterial isolate containing the iha gene, compared to the isolate containing the kps gene. Microspheres of …


Deuterium And Oxygen-18 Diffusion In A Confined Aquifer: A Numerical Model Of Stable Isotope Diffusion Across Aquitard-Aquifer Boundaries, Benjamin J. Currens Jan 2016

Deuterium And Oxygen-18 Diffusion In A Confined Aquifer: A Numerical Model Of Stable Isotope Diffusion Across Aquitard-Aquifer Boundaries, Benjamin J. Currens

Theses and Dissertations--Earth and Environmental Sciences

The stable isotopes 2H and 18O, combined with noble gases and radioisotopes (e.g., 3H, 14C, 36Cl), are used to infer groundwater age and climate during recharge. Flow regimes within low-velocity flowpaths and long residence times could allow an aquitard-aquifer diffusive flux to alter isotope abundance. Consequently, the diffusion of isotopes (e.g., 14C, 2H and 18O) between aquifers and confining layers needs to be considered in such conditions. In this study, COMSOL Multiphysics was used to determine if diffusion of 18O (and 2H by proxy) from a bounding aquitard could explain …


Spring Responses To Storms And Seasonal Variations In Recharge In The Middle Atlas Region Of Morocco, Brett Andrew Howell Jan 2016

Spring Responses To Storms And Seasonal Variations In Recharge In The Middle Atlas Region Of Morocco, Brett Andrew Howell

Theses and Dissertations--Earth and Environmental Sciences

Springs in the Middle Atlas Mountains of Morocco are significant sources for public water supply. From March 2014 to May 2015, water temperatures were measured hourly at three springs (Ribaa, Sidi Rached, and Zerouka); water levels were measured hourly at Sidi Rached and Zerouka; and daily turbidity data were obtained from Ribaa. From March 2014 to March 2015, daily water samples were taken at Zerouka for analyses of the stable isotopes deuterium and oxygen-18. Hourly weather data (precipitation and air temperature) were available from March 2014 to May 2015 from Ifrane, near Zerouka. Temperature responses varied between the springs, showing …