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Full-Text Articles in Physical Sciences and Mathematics
Fate Of Stable Isotope Label During Predation Of 15N-Tagged Wild-Type Escherichia Coli By Protozoa, Ashley M. Barton
Fate Of Stable Isotope Label During Predation Of 15N-Tagged Wild-Type Escherichia Coli By Protozoa, Ashley M. Barton
University of Kentucky Master's Theses
Currently, bacterial movement in karst aquifers is not well understood. Use of stable isotopes to label non-pathogenic Escherichia coli as a particulate groundwater tracer in karst systems has been examined in previous studies. Loss of the stable isotope signal is anticipated in traces greater than 500 m in length. Potential loss of 15N due to predation by protozoa was examined. Filter-sterilized water from Royal Spring in Georgetown, Kentucky, was inoculated with a mixture of either Tetrahymena pyriformis or Colpoda steinii and 15N-enriched E. coli and stored in the dark at 14°C. Samples were analyzed for their nitrogen isotope …
Latest Quaternary Paleoclimate Reconstruction Utilizing Stable Isotopic And Trace Element Proxies In A Stalagmite From Culverson Creek Cave, West Virginia, Ashley Nicole Gilbert
Latest Quaternary Paleoclimate Reconstruction Utilizing Stable Isotopic And Trace Element Proxies In A Stalagmite From Culverson Creek Cave, West Virginia, Ashley Nicole Gilbert
University of Kentucky Master's Theses
A reconstruction of regional climate variability in southern West Virginia that spans the last glacial/interglacial transition is presented. Paleoclimate interpretations obtained from the 50-cm long stalagmite provide key insights regarding the timing, magnitude, and forcing mechanisms responsible for past climate variability. Stable isotopic (δ18O and δ13C) and trace element (Ba, Sr, Mg) signatures from samples contiguously milled along the growth-axis of a 230Th-dated stalagmite which grew between approximately 20 and 5 thousand years before present (kyr BP) provide critical constraints for above-cave mean annual temperature, seasonality of moisture mean annual precipitation, and potential vegetation shifts. …