My research falls into three major categories listed below. Although these topics appear to be unrelated, they are all linked in their focus on fluxes of water across interfaces, or more simply stated, surface water and ground water (broadly defined) interactions. These interactions include quantity of water exchanged across the sediment-water interface, chemical influence of this exchange on both surface water and groundwater quality, diagenetic alteration of aquifer rocks and sediments, and alteration of sediments through which water flows.
Physical and chemical hydrogeology of carbonate aquifers
Most of my research on karst aquifers has been on the Floridan aquifer, but I have also been working extensively in the Bahamas and lately in the Yucatan. My research focuses on how water flowing through conduits exchanges with water of the high-porosity matrix rocks. I have also been active in developing tools to measure and predict fluxes of nutrients through carbonate karst watersheds. I am currently working on a project to study the effects on metal diagenesis and organic carbon remineralization as high organic carbon content water reverses into springs during flooding.
Sea level change and impact to coastal aquifers
I am interested in quantifying flux of water from coastal aquifers and its significance to water quality in estuarine and coastal surface water. This work has focused mostly on Indian River Lagoon on the east coast of peninsular Florida, but other areas include Tampa Bay, Bahamas, Barbados, Brazil and the Yucatan. One particular focus of this work is the redox chemistry (particularly of metals) of the pore water of the lagoon sediment and the relationships between reminerallization of organic carbon, discharge from the aquifers, and metal chemistry. I recently have started a project that will study the effects of sea level rise on these estuarine processes. See this link for more information.
Weathering of Greenland and marine records of glacial retreat
Collapse of continental ice sheets are recorded in the variation of radiogenic isotope signatures (Sr, Nd, and Pb) of deep sea cores. The changes in the isotope ratios result from variations in weathering of continental material, and the age of that material, as glaciers retreat and exposing fresh material to weathering. I am currently working on the west coast of Greenland to assess the fluxes of radiogenic isotopes from different watersheds including rivers discharging from sub-glacial and pro-glacial areas to compare with rivers discharging from de-glaciated watersheds.