SARAH DAILY PUGH

Research Interests: A Comparison of Riparian Plant Rhizosphere Bacteria in Semi-arid and Mesic Habitats

Entry into IGERT Program: Fall 2002
Graduation Date:  December 2007 (Ph.D.)
Professional Address:
   Biology Instructor, Shelton State Community College
   9500 Old Greensboro Road
   Tuscaloosa, AL 35405

 

Education:

B.S. Zoology, 2001
The Ohio State University

Graduate Committee:

Dr. Amy Ward (UA), Co-Major Advisor
Dr. Julie Olson (UA), Co-Major Advisor
Dr. Perry Churchill (UA)
Dr. Eric Roden (Univ. Wisconsin, Madison)
Dr. Christina Takacs Vesbach (UNM)

Externship:

I am serving as an adjunct faculty member at Samford University, Birmingham, Alabama, where I teach an interdisciplinary Scientific Methods course as well as a Human Biology course. This externship has provided me with the opportunity to explore and familiarize myself with teaching at a small, private institution.





 

 

RESEARCH PROJECT

    The plant rhizosphere contains microbial populations that are nearly 100 times higher than populations found in adjacent root free soil. It is recognized that the microbial diversity found within the rhizosphere is dependent upon physiological processes of different species and environmental factors which may include light intensity and soil conditions such as moisture, temperature, and pH. Because the rhizosphere contains such high microbial diversity, it is important to consider the various factors affecting these communities and their implications on the ecosystem's structure and function.

    Riparian habitats associated with the Rio Grande (New Mexico) and Mobile River (Alabama) systems offer opportunities to compare and contrast plants of similar function in semi-arid versus humid, wet regions of the U.S. This project compares and contrasts environmental and physiological characteristics of riparian plants in these two settings. Elaeagnus angustifolia (Russian olive) and Alnus serrulata (Hazel alder) are both actinorhizal, riparian plants that have the potential to make significant contributions of nitrogen to riverine ecosystems via nitrogen fixation associated with Frankia root nodules. However, Russian olive is highly drought tolerant, intolerant of anoxic conditions, and an invasive species that is threatening native cottonwood plants. Hazel alder is native to the U.S., not drought resistant, but highly tolerant of anaerobic soil conditions.

    Our primary working hypothesis is that the rhizosphere bacterial community, including nitrogen fixing components, is important to overall success of each plant, but rhizosphere bacterial composition differs between plant species in significant ways because of differences in relative environmental tolerances of each plant.