Fate of stable isotope label during predation of 15N-tagged wild type Escherichia coli by protozoa
Document Type
Dissertation
Publication Title
MS Thesis, Department of Earth and Environmental Sciences, University of Kentucky
Abstract
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 composition (as δ15N values), and for population counts of bacteria and protozoa in a time course experiment, on days zero and seven after inoculation. Protozoan populations increased in the presence of E. coli, while bacterial populations decreased. δ15N values increased in T. pyriformis fed enriched E. coli but did not show values as high as the bacteria themselves, indicating that attenuation via predation may be a concern in future groundwater traces.
Publication Date
2011
Recommended Citation
Barton, Ashley M., "FATE OF STABLE ISOTOPE LABEL DURING PREDATION OF 15N-TAGGED WILD-TYPE ESCHERICHIA COLI BY PROTOZOA" (2011). University of Kentucky Master's Theses. 146. https://uknowledge.uky.edu/gradschool_theses/146