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UC San Diego UC San Diego Electronic Theses and Dissertations Title Effects of food web interactions and climate on the partial pressure of carbon dioxide in San Diego reservoirs / Permalink https://escholarship.org/uc/item/31k0s9nx Author Adamczyk, Emily Mei-Ying Publication Date 2014 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA, SAN DIEGO Effects of food web interactions and climate on the partial pressure of carbon dioxide in San Diego reservoirs A Thesis submitted in partial satisfaction of the requirements for the degree Master of Science in Biology by Emily Mei-Ying Adamczyk Committee in charge: Professor Jonathan B. Shurin, Chair Professor Elsa E. Cleland Professor Michael R. Landry 2014 Copyright Emily Mei-Ying Adamczyk, 2014 All rights reserved. The Thesis of Emily Mei-Ying Adamczyk is approved and it is acceptable in quality for publication on microfilm and electronically: Chair University of California, San Diego 2014 iii DEDICATION I would like to dedicate this thesis to my aunt, Christine Lwe, who has proven time after time that cherishing every moment in life and keeping one’s spirits high are the best ways to be happy. Her strength and positive outlook encouraged me to keep pushing forward even when I just wanted to drop it all; she has showed me that it is possible to remain hopeful even in one’s weakest moments. For that, I am forever grateful. I miss her immensely and hope that she is enjoying her journey throughout the Pacific Ocean and the waters of worlds beyond. iv TABLE OF CONTENTS Signature Page…………………………………………………………………… iii Dedication……………………………………………………………………...... iv Table of Contents………………………………………………………………... v List of Abbreviations…………………………………………………………….. vi List of Symbols………………………………………………………………….. vii List of Figures…………………………………………………………………… viii List of Tables…………………………………………………………………….. x Acknowledgements……………………………………………………………… xi Abstract of the Thesis…………………………………………………………… xii Introduction……………………………………………………………………… 1 Methods and Materials…………………………………………………………... 6 Results……………………………………………………………………………. 13 Discussion………………………………………………………………………... 17 Figures………………………………………………………………………….... 23 Tables…………………………………………………………………………….. 36 Appendix……………………………………………………………………….... 37 References…....…………………………………………………………………... 38 v LIST OF ABBREVIATIONS chl-a …………………………………………………...……...chlorophyll-a (μg L-1) DAPI …………………………………………………4',6-diamidino-2-phenylindole DI ……………………………………………………………………….deionized DO ……………………………………..……………….dissolved oxygen (mg L-1) DOC ………………………………………..….dissolved organic carbon (mg C L-1) GHG ………………………………………………………………….greenhouse gas PBS ………………………………………………………phosphate buffered saline POC ………………………………..………...particulate organic carbon (mg C L-1) POM ………………………………………………………particulate organic matter PON ……………………………..………….particulate organic nitrogen (mg N L-1) ppt ………………………………………………………………parts per thousand psi …………………………………………………………pounds per square inch TA ……………………………………………………….…..total alkalinity (ppm) TN ………………………………………….……………total nitrogen (mg N L-1) TP ……………………………………………..…….total phosphorous (mg P L-1) vi LIST OF SYMBOLS C …………………………………………………………………………….carbon ⁰C ..………………………………………………………………degrees centigrade CH4 ..…………………………………………………………………………methane cm ………………………………………………………………………...centimeter CO2 ……………………………………………………………………carbon dioxide Hg …………………………………………………………………………..mercury km …………………………………………………………………………kilometer L ……………………………………………………………………………….liter m ..……………………………………………………………………………meter mg …………………………………………………………………………milligram mL ………………………………………………………………………….milliliter mm ………………………………………………………………………...millimeter μ ……………………………………………………………………………..micro N …………………………………………………………………………..nitrogen P ……………………………………………………………………….phosphorus p …………………………………………………………………………...p-value pCO2 ………………………………………………..partial pressure of carbon dioxide S …………………………………………………………………………...siemens 푋̅ ……………………………………………………………………………...mean vii LIST OF FIGURES Figure 1. Sources of San Diego County’s water supply……………………… 23 Figure 2. Twenty-four major reservoirs in San Diego County……………...... 24 Figure 3. Partial pressure of carbon dioxide (pCO2) in ppm for 50 sampling 25 weeks…………………………………………………………………………….. Figure 4. Significant drivers of pCO2 across all reservoirs…………………… 26 Figure 5. Phytoplankton biomass for each reservoir as measured by 27 chlorophyll-a (μg L-1) for 50 sampling weeks…………………………………... Figure 6. Total nitrogen (TN) concentrations (mg N L-1) for each reservoir for 27 50 sampling weeks………………………………………………………………. Figure 7. Total phosphorus (TP) concentrations (mg P L-1) for each reservoir 28 for 50 sampling weeks…………………………………………………………... Figure 8. pH for each reservoir for 50 sampling weeks………………………. 28 Figure 9. Significant drivers of pH across all reservoirs……………………… 29 Figure 10. Zooplankton community biomass (mg L-1) for all reservoirs for 49 30 sampling weeks………………………………………………………………….. Figure 11. Zooplankton community average length (mm) for all reservoirs over 30 50 sampling weeks………………………………………………………………. Figure 12. Bacteria abundance (# L-1) for all reservoirs for 50 sampling 31 weeks….................................................................................................................. Figure 13. Chytrid abundance (# L-1) for all reservoirs for 50 sampling 31 weeks……………………………………………………………………………. viii Figure 14. Dissolved organic carbon (DOC) concentrations (mg C L-1) for all 32 reservoirs for 50 sampling weeks………………………………………………... Figure 15. Particulate organic carbon (POC) concentrations (mg C L-1) for each 32 reservoir for 50 sampling weeks………………………………………………… Figure 16. Particulate organic nitrogen (PON) concentrations (mg N L-1) for 33 each reservoir for 50 sampling weeks…………………………………………… Figure 17. Carbon/nitrogen (C/N) molar ratios for all reservoirs over 50 33 sampling weeks………………………………………………………………….. Figure 18. Minimum and maximum water temperatures (⁰C) for each reservoir 34 over 37-38 sampling weeks from Sept 2013-June2014…………………………. Figure 19. Surface and bottom dissolved oxygen (DO) concentrations (mg L-1) 35 for all reservoirs over 28-30 sampling weeks…………………………………… ix LIST OF TABLES Table 1. Multiple regression model for partial pressure of carbon dioxide 36 (pCO2) as a function of variables sampled………………………………………. Table 2. Multiple regression model for pH as a function of variables sampled... 36 x ACKNOWLEDGEMENTS First and foremost, I would like to thank my advisor, Professor Jonathan Shurin, for whom I am tremendously grateful for providing me the opportunity to conduct research in his lab for my master’s thesis. His enthusiastic encouragement and unwavering guidance throughout both my field work, statistical analysis, and writing have played a crucial role in the accomplishment of this thesis and working with him has proved to be one of the most rewarding experiences of my academic career thus far. I would also like to acknowledge the rest of my committee, Professor Elsa Cleland and Professor Michael Landry, for their advice and support in both field methods and writing. Additionally, I would like to acknowledge Celia Symons for her expertise in field work and inspiring me to pursue research in freshwater ecology. I would like to thank Steven and Cindy Villareal for their hard work in running the Shurin lab smoothly and analyzing my nutrient samples; Jake Keeney for his tenacity in counting bacteria and fungi; Lihini Aluwihare and Magali Porrachia for their help analyzing DOC; Bruce Deck for running all my POM samples; Joris Beld for generously supervising my FAME analyses; Brian Hong and Akana Noto for their friendship, encouragement, and assistance with R; Shovon Mandal for his instruction in determining microbial biomass; Matthew Young for his diligent help in the field; Patrick Keith, Alexis Davis, Matthew Tan, and Eric Barber for their help in the arduous tasks of counting and photographing zooplankton; Steven Rick for assisting with field pictures and his endless support; and my parents, John and Margaret Adamczyk, for always encouraging me to pursue my dreams and goals no matter how challenging the road to success may be. xi ABSTRACT OF THE THESIS Effects of food web interactions and climate on the partial pressure of carbon dioxide in San Diego reservoirs by Emily Mei-Ying Adamczyk Master of Science in Biology University of California, San Diego, 2014 Professor Jonathan B. Shurin, Chair Man-made reservoirs around the world contribute to cycling of carbon dioxide (CO2) with the atmosphere, but there is little information on how ecosystem processes determine the absorption or emission of CO2. It is essential to determine if reservoirs sequester or release CO2 to understand how water impoundments impact global carbon cycling. We sampled three reservoirs throughout San Diego, California, all of which receive most of their water from Northern California and the Colorado River, weekly for one year. We measured seasonal variation in the abundances of bacteria, pelagic fungi, xii phytoplankton, and zooplankton, as well as abiotic factors such as water chemistry (pH, nutrients, conductivity, ions, dissolved organic carbon [DOC], and partial pressure of CO2 [pCO2]). We found that San Diego reservoirs are most often undersaturated with CO2 with respect to the atmosphere and vary seasonally in both different trophic level abundances and pCO2. pCO2 was highest in the winter and lower in the summer, indicating seasonal shifts in the magnitudes of photosynthesis