Degree Granting Department
Peter J. Harries, Ph.D.
Jonathan G. Wynn, Ph.D.
Bogdan P. Onac, Ph.D.
Diana E. Northup, Ph.D.
Henry L. Vacher, Ph.D.
karst, dissolution, limestone, microbes, geochemistry
Microbes are prevalent in geologic settings and a growing body of research
suggests the roles they play in geologic processes may be more important than
previously thought, and therefore underestimated. This dissertation addresses the
influence of microbes on the dissolution of limestone in karst settings by analyzing the
stable carbon isotopes and geochemistry of air and waters from three unique cave and
karst settings: West-Central Florida, the Everglades (southern Florida) and The
Bahamas. In Florida, these parameters as well as air/water temperature, rainfall, and
water-level fluctuations were monitored for 22 and 10 months. In the Bahamas,
geochemical data were collected from at varying time-intervals from a variety of cave
and surface water bodies. Results showed that microbial respiration in these
environments is an important source of carbon dioxide, which contributes to the
formation of carbonic acid, which appears to be the major dissolving agent at each of
these sites. At the same time, microbially-mediated oxidation of both organic matter and
minerals exerts a secondary dissolution control by providing additional acid and
inorganic ions that dissolve rock and/or inhibit limestone precipitation.
This dissertation also includes a chapter discussing the role of the USF
Department Geology in the evolution of assessment for
Spreadsheets Across the
(SSAC) project, which promotes quantitative literacy (QL) by teaching math
in the context of other disciplines. Assessment occurred primarily in the Computational
Geology course from 2005 to 2008 and showed that this teaching strategy fostered
gains in math knowledge and positive math association. Simultaneously, instructors
learned that pre-planning and adaptability was central to developing a successful
assessment strategy, which, when combined with the heterogeneity of subjects each
year, presents challenges in the yearly comparison of results. These conditions are
common in educational settings, illustrating the impracticality of standardized
assessment instruments and practices, and the importance of the extensive preparation
required in identifying assessment goals and the best strategies for achieving them in a
Scholar Commons Citation
McGee, Dorien Kymberly, "Microbial Influences on Karst Dissolution: The Geochemical Perspective, with a Chapter on Assessment of the Spreadsheets Across the Curriculum Project" (2010). Graduate Theses and Dissertations.