The Seasonality of Oxygen and Hydrogen Isotopes of Rain, Stream and Groundwater in Fredericksburg, VA
Date of Award
Bachelor of Science
Earth and Environmental Sciences
Department Chair or Program Director
Major or Concentration
Stable isotopes of oxygen and hydrogen, δ18O and δD, are tracers of climatic changes within the hydrologic cycle, and thus are a potential link in the relationship between climate-influenced changes to the hydrologic cycle and modern and paleoenvironments. Studies have shown that the isotopic content of surface water and groundwater parallel meteoric water (e.g. Dutton et al., 2005), a relationship expected to be reflected in marine paleoclimate archives, such as those from the Chesapeake Bay, which are sensitive to freshwater input from rivers (e.g. LeGrande and Schmidt, 2009). In this study, we establish a baseline of isotopic composition of precipitation, stream, and groundwater in Fredericksburg, Virginia, to study the seasonality of δ18O and δD within the water. We have found precipitation in winter months to be more depleted in heavy isotopes than in warmer months, indicating the influence of temperature on isotopic abundance. Periods of high rainfall frequency result in greater variability of the δ18O and δD of stream water; however, periods of prolonged dryness resulted in deviations of this trend due to high rates of evaporation and the inflow groundwater into the stream. This work will provide the foundation of using δ18O and δD of meteoric water to study changing precipitation patterns as climate changes in the local Fredericksburg, VA region, as well as understanding the controls of the δ18O and δD of surface water for more robust interpretations from proxy records in regional paleoclimate studies.
Elliott, Kathleen C.; Grothe, Pamela R.; and Konecky, Bronwen, "The Seasonality of Oxygen and Hydrogen Isotopes of Rain, Stream and Groundwater in Fredericksburg, VA" (2019). Student Research Submissions. 273.