Browsing by Subject "Ohio River Valley"

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    Carbon, Oxygen, and Nitrogen Isotopic Analysis of Mollusca: Unionidae of the Ohio River System during the Anthropocene
    (Office of the Vice Chancellor for Research, 2014-04-11) Conduitt, Chelsea L
    Isotopic compositions of Obovaria olivaria, Leptodea fragilis, and Quadrula quadrula of the Wabash River contain clues to the anthropogenic modifications they have undergone during the time of the shell formation. In this study we analyzed the isotopic composition of the carbon (δ13C), oxygen (δ18O), and nitrogen (δ15N) in the carbonate sampled from growth bands of the shells. These results are compared to published data, and with accurately documented historical river data to better understand the human impact on river systems in the Ohio River Valley in the last 250 years. Mollusks construct their shells using CO2 and nitrogen that is dissolved in the water. Since mollusks are sedentary animals, their isotopic signatures will reflect the chemistry of the water in which they grow. Comparing the locality in which the mollusks lived to the chemical changes recorded in their shells over time will provide temporal-spatial constraints on the natural variability of the river as well as the influence of anthropogenic inputs. Specifically, the δ13C and δ18O stored in the shells of the mollusks record changes in the environment such as air and river temperature, acidity of the river, changes in the river chemical composition, and may indicate a change in the source of the water. The isotopic analysis of δ15N recovered from the shell can help track changes in nutrient delivery during the time of shell formation. Through this geochemical study we hope to provide a much needed record of the timing and extent of human impact on river systems.
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    Rivers of the Anthropocene Phase 1: A Comparative Study of the Tyne and Ohio River Valleys
    (Office of the Vice Chancellor for Research, 2014-04-11) Stump, Aaron M.; Bird, Broxton W.; Wilson, Jeremy J.
    The Rivers of the Anthropocene project is an international effort. Our part is an attempt to determine flood frequency and land use by American Indian tribes of the Mississippian Culture along the Ohio River. Methodologically, we will measure the physical and geochemical properties of lacustrine sediments recovered from Hovey Lake, a flood plane lake located on the Ohio River in southwestern Indiana. Sediment cores taken from Hovey Lake are being measured for bulk density and loss-on-ignition tests to determine organic composition by weight. Magnetic susceptibility is also being measured to determine variations in the delivery of terrestrial material (e.g. from flooding/land erosion) to the lake. Land use will be evaluated by measuring variations in the elemental abundance and isotopic composition of nitrogen and organic carbon, which has been used in the past to identify prehistoric land use. Here we present the initial results of our ongoing work, including sedimentological and chronological data. Ultimately, these data will help bring together historical records, geochemical records, and other contributions from scientists around the world in our attempt to better understand mankind’s impact on our environment.