University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School January 2013 Direct and Indirect Effects of Agrochemicals on Bacterial Pathogens and Fecal Indicator Bacteria Zachery Staley University of South Florida, [email protected] Follow this and additional works at: http://scholarcommons.usf.edu/etd Part of the Microbiology Commons Scholar Commons Citation Staley, Zachery, "Direct and Indirect Effects of Agrochemicals on Bacterial Pathogens and Fecal Indicator Bacteria" (2013). Graduate Theses and Dissertations. http://scholarcommons.usf.edu/etd/4584 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Direct and Indirect Effects of Agrochemicals on Bacterial Pathogens and Fecal Indicator Bacteria by Zachery R. Staley A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Integrative Biology College of Arts and Sciences University of South Florida Co-Major Professor: Valerie J. Harwood, Ph. D. Co-Major Professor: Jason R. Rohr, Ph. D. Kathleen M. Scott, Ph.D. John T. Lisle, Ph. D. Date of Approval: March 26, 2013 Keywords: Water Quality, Protozoa, Pesticides, Sediment, Viruses Copyright © 2013, Zachery R. Staley DEDICATION I would like to dedicate this dissertation to my parents, Ruth Lawrence and Floyd Staley. Without your love and support this would not have been possible. Additionally, I would like to dedicate this work to my friends, Ryan Sherman, Jake Sears, Jonathan Jeerapaet, Alex Brewer, Cory Larkin, Kyle Spidel, Jeremiah Callahan, and Emily Grennor. You all have been like family to me and I would have never gotten this far without you in my life. This dedication is a small token of how much I value all of you and appreciate the significant contributions you have made and continue to make to my life. ACKNOWLEDGMENTS I would like to express my sincere thanks to Dr. Valerie J. Harwood and Dr. Jason R. Rohr, my mentors and advisors, for all the guidance, advice and direction they have given me over the years. I would also like to thank my committee members, Dr. Kathleen M. Scott and Dr. John T. Lisle for their time and suggestions throughout the course of my graduate studies. Further, I would like to acknowledge Dr. James T. Riordan for accepting to serve as the chair person for my dissertation defense. Special thanks are also due to the former and current members of the Harwood lab (Miriam Brownell, Asja Korajkic, Brian Badgley, Shannon McQuaig, Chris Staley, Katrina Gordon, Bina Nayak, Stephaney Leskinen, Dawn Hunter, Eva Chase, Pauline Wanjugi, and Suzanne Young) for their friendship and support. I would also like to thank my undergrads (Kennon Hydock, Melissa Tamayo, Diana Contreras, Laura Duran, Hannah Wapshott, and especially Jacob Senkbeil) for their contribution to and help on my research. Lastly, I must thank the cat, Ms. Persephone “Lumpy” Farris, for providing relief and distraction as needed. TABLE OF CONTENTS LIST OF TABLES ............................................................................................................. iv LIST OF FIGURES .............................................................................................................v ABSTRACT ................................................................................................................... vii CHAPTER ONE: EFFECTS OF AGROCHEMICALS ON MICROORGANISMS .........1 Introduction ..............................................................................................................1 Direct and Indirect Effects .......................................................................................5 Agrochemical Effects...............................................................................................6 Insecticides ...................................................................................................7 Herbicides ..................................................................................................13 Fungicides ..................................................................................................18 Ecological Relevance and Areas for Further Research ..........................................21 References ..............................................................................................................23 CHAPTER TWO: THE EFFECT OF AGROCHEMICALS ON INDICATOR DENSITIES IN OUTDOOR MESOCOSMS ............................................................35 Summary ................................................................................................................35 Introduction ............................................................................................................36 Results ....................................................................................................................38 Discussion ..............................................................................................................41 Experimental Procedures .......................................................................................45 Experimental Design ..................................................................................45 Bacterial Inoculation ..................................................................................47 Sample Collection and Filtration ...............................................................48 Statistical Analyses ....................................................................................49 Acknowledgments..................................................................................................51 References ..............................................................................................................51 CHAPTER THREE: A TEST OF DIRECT AND INDIRECT EFFECTS OF AGROCHEMICALS ON THE SURVIVAL OF FECAL INDICATOR BACTERIA ................................................................................................................61 Summary ................................................................................................................61 Introduction ............................................................................................................62 Experiment Design.................................................................................................66 Direct Effects Experiment..........................................................................66 Indirect Effect Experiment .........................................................................69 Sample Collection and Filtration ...............................................................70 i E. coli Genetic Typing ...............................................................................71 Statistical Analysis .....................................................................................73 Direct Effect Experiment ...........................................................................73 Treatment Effects on FIB Abundance ...........................................73 Treatment Effects on FIB Composition .........................................74 Relationship Between FIB Composition in the Sediment and Water Column .....................................................................................74 Indirect Effect Experiment .........................................................................75 Results ....................................................................................................................75 Direct Effects of Agrochemicals (Dark Conditions) .................................75 Indirect Effects of Agrochemicals (Light Conditions) ..............................77 Discussion ..............................................................................................................79 Acknowledgments..................................................................................................84 References ..............................................................................................................84 CHAPTER FOUR: LACK OF DIRECT EFFECTS OF AGROCHEMICALS ON ZOONOTIC PATHOGENS AND FECAL INDIATOR BACTERIA .....................96 Abstract ..................................................................................................................96 Introduction ............................................................................................................96 Experimental Design ..............................................................................................98 Microcosm Establishment ..........................................................................98 Bacterial Enumeration .............................................................................100 Growth Curves .........................................................................................100 Statistical Analysis ...................................................................................101 Results ..................................................................................................................102 Discussion ............................................................................................................103 Acknowledgments................................................................................................104 References ............................................................................................................104