A Thesis entitled Diel Vertical Distribution of Microcystis and Associated Environmental Factors in the Western Basin of Lake Erie by Eva L. Kramer Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Biology ___________________________________________ Dr. Thomas Bridgeman, Committee Chair ___________________________________________ Dr. Timothy Davis, Committee Member ___________________________________________ Dr. Daryl Moorhead, Committee Member ___________________________________________ Dr. Cyndee Gruden, Dean College of Graduate Studies The University of Toledo December 2018 Copyright 2018, Eva Lauren Kramer This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of Diel Vertical Distribution of Microcystis and Associated Environmental Factors in the Western Basin of Lake Erie by Eva L. Kramer Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Biology The University of Toledo December 2018 Harmful algal blooms comprised of the cyanobacteria Microcystis have recently caused multiple “do not drink” advisories in Ohio communities that draw their drinking water from Lake Erie, including the city of Toledo. Microcystis colonies are able to regulate their buoyancy and have a tendency to aggregate in thick scums at the water’s surface on a diel cycle under certain conditions. The city of Toledo’s drinking water intake draws water from near the bottom of the water column, thus a concentration of the bloom near the surface would present an opportunity to minimize Microcystis biomass and microcystin toxin entering the drinking water system. To better understand the vertical distribution of Microcystis over diel cycles, five temporally intensive sampling events were conducted from 2016-2017 under calm weather conditions near the drinking water intake in the western basin of Lake Erie. In-situ vertical profiles of algal concentrations and environmental parameters were recorded, and water samples were collected from discrete depths for algal identification and laboratory analysis of chlorophyll a, phycocyanin, microcystin, and nutrient concentrations. A scum was observed on only one of the five sampling events; unexpectedly, Microcystis decreased near the surface in the middle of the day during three of the five events. Total water iii column Microcystis decreased throughout each sampling event, possibly due to settling. Toxin distributions did not reflect cyanobacterial distributions. Therefore, real-time monitoring of cyanobacteria and toxin remain important tools for the management of Toledo’s drinking water. iv This thesis is dedicated to those who have made it possible through their constant support and love: my husband, Greg Lytmer; my parents, David and Peggy Kramer; and my Forest Family, you know who you are. v Acknowledgements I would like to thank my advisor, Dr. Thomas Bridgeman, for all of his help and guidance with this research. I would also like to thank my committee, Dr. Timothy Davis for his help and expertise in algal ecology, and Dr. Daryl Moorhead for his guidance on data analysis. This work would not have been possible without the additional lab and field support of my colleagues at the Lake Erie Center: Brenda Snyder, Zach Swan, Alex Lytten, Ken Gibbons, Joe Turner, Lucas Arend, Jenna Houdashelt, Rachel Lohner, and Pam Struffolino. Special thanks to Christian Moldaenke of bbe Moldaenke for field and instrumentation support and Dr. Douglas Kane for field assistance. Further assistance was provided by the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory; I would like to thank Dr. Mark Rowe for guidance on data analysis and David Fanslow for providing FlowCam data. I would also like to thank Dr. Dragan Isailovic and Dilrukshika Palagama for providing liquid chromatography-mass spectrometry data. Finally, I would like to thank the Lake Erie Center for use of their boat and laboratory space, and the Ohio Department of Higher Education for funding this study. vi Table of Contents Abstract .............................................................................................................................. iii Acknowledgements ............................................................................................................ vi Table of Contents .............................................................................................................. vii List of Tables ..................................................................................................................... ix List of Figures ......................................................................................................................x List of Abbreviations ....................................................................................................... xiii 1 Diel Vertical Distribution of Microcystis in the Western Basin of Lake Erie .........1 1.1 Introduction ........................................................................................................1 1.2 Methods..............................................................................................................6 1.2.1 Field Sampling ....................................................................................6 1.2.2 Vertical Profiles ..................................................................................7 1.2.3 Full Sample Collection .......................................................................8 1.2.4 Laboratory Analysis ............................................................................9 1.3 Results ..............................................................................................................13 1.3.1 Overview of Study Results ...............................................................13 1.3.2 Sampling Events ...............................................................................16 1.3.2.1 August 3-4, 2016 ................................................................16 1.3.2.2 August 18, 2016 .................................................................23 1.3.2.3 August 9-10, 2017 ..............................................................28 vii 1.3.2.4 August 15, 2017 .................................................................33 1.3.2.5 September 25, 2017 ...........................................................38 1.3.3 Depth-Integrated Microcystis Biomass Estimates ............................43 1.3.4 Analytical Methods Comparisons .....................................................45 1.4 Discussion ........................................................................................................51 1.4.1 Vertical Distributions of Microcystis ................................................51 1.4.2 Capturing the Full Water Column.....................................................52 1.4.3 Implications for Drinking Water Management .................................54 1.4.4 Recommendations for Future Studies ...............................................55 References ..........................................................................................................................57 A Supplementary Figures ..........................................................................................62 viii List of Tables 1.1. Sampling event dates and time ranges .................................................................... 7 1.2. Summary of all measured parameters and sources of final data ........................... 12 ix List of Figures 1-1. Location of Toledo drinking water intake and sampling site ...................................... 6 1-2. MODIS satellite imagery of WBLE bloom conditions on sampling dates ............... 13 1-3. Comparison of total microcystin concentrations across all sampling events. ........... 16 1-4. Chlorophyll a concentrations measured using the YSI. August 3-4, 2016 ............... 17 1-5. Chlorophyll a concentrations measured using the FP. August 3-4, 2016.................. 18 1-6. Temperature profiles measured using the YSI. August 3-4, 2016 ............................ 19 1-7. ODO concentrations measured using the YSI. August 3-4, 2016 ............................. 20 1-8. pH measured using the YSI. August 3-4, 2016 ......................................................... 20 1-9. Vertical profiles of algal concentrations measured with the FP on August 3, 2016. 21 1-10. Cyanobacteria and microcystin concentrations at discrete depths. August 3-4, 2016 ............................................................................................................................... 22 1-11. Chlorophyll a concentrations measured using the YSI. August 18, 2016 ............... 23 1-12. Chlorophyll a concentrations measured using the FP. August 18, 2016 ................. 24 1-13. Temperature profiles measured using the YSI. August 18, 2016 ............................ 24 1-14. ODO concentrations measured using the YSI. August 18, 2016 ............................ 25 1-15. pH measured using the YSI. August 18, 2016 ........................................................ 25 1-16. Vertical profiles of algal concentrations measured with the FP on August 18, 2016 ............................................................................................................................... 26 x 1-17. Cyanobacteria and microcystin concentrations