Trophic transfer of metals and OCP’s in organisms from a warm temperate and a subtropical intertidal rocky shore CJ Greyling orcid.org/0000-0001-8505-8583 Dissertation submitted in fulfilment of the requirements for the degree Master of Science in Environmental Sciences at the North-West University Supervisor: Prof V Wepener Co-supervisor: Prof Y Ikenaka Graduation May 2018 23599235 Acknowledgements Writing a dissertation takes determination and patience and most of all support. This research would not have been completed without the contributions and assistance of many. I want to extend my greatest appreciation to the following people and institutions: To my supervisor, thank you for providing me with the opportunity to do research in a field that I love. Thank you for your support during fieldtrips and in the laboratory, for all the knowledge and encouragement to finish this project and all the long hours of reviewing. The NWU Water Research Group for funding of the project and every opportunity to further my knowledge and passion in this field. Prof. Mayumi Ishizuka, Prof. Yoshinori Ikenaka, Dr. Shouta Nakayama, Dr. Yared Beyene, Ichise-san, Ishii-san, Aksorn-san, Mizukawa-san, Lesa and everyone from the Toxicology Laboratory at the Graduate School of Veterinary Medicine Hokkaido University, for their hospitality, assistance, the opportunities and organization to analyse samples for stable isotope analysis. Prof. van Vuren for advice and the organization of my travels to Japan. Claire Volschenk (neé Edwards) for her assistance, advice and early mornings in Japan. Prof. Rialet Pieters, Tash Vogt, Suranie Horn and Nico Wolmarans for their assistance during the organic extractions. Thank you for taking the time to guide me on the right track and opening your laboratory for my analysis. Dr. Wynand Malherbe for his unconditional unofficial supervision. Thank you for always being willing to help. I would also like to extend my appreciation to colleagues and friends Dr. Kerry Hadfield Malherbe, Dr. Ruan Gerber, Elané, Anrich, Uané, Lizaan, Marelize and everyone at the NWU Water Research Group for their support and advice during the course of my project. Also, great thanks to my family for their endless support and the opportunity to finish this research with a smile on my face. To Hannes Erasmus, thanks for your constant love and support, advice and guidance during the past few years. You inspire me in everything you do. Thank you God for the opportunity and willpower to complete this project. pg. i Table of Contents Acknowledgements _____________________________________________________________ i Table of Contents _____________________________________________________________ ii Summary ____________________________________________________________________ v List of Figures ________________________________________________________________ viii List of Tables _________________________________________________________________ x 1. CHAPTER 1: GENERAL INTRODUCTION _________________________________________ 1 1.1. Introduction ____________________________________________________________ 1 1.1.1. South African coastal diversity __________________________________________ 1 1.1.2. Study rational _______________________________________________________ 3 1.2. Hypotheses, aims & objectives _____________________________________________ 4 1.2.1. Hypotheses _________________________________________________________ 4 1.2.2. Aims _______________________________________________________________ 4 1.2.3. Objectives __________________________________________________________ 5 2. CHAPTER 2: STUDY AREA AND SPECIES DESCRIPTION _____________________________ 6 2.1. Tsitsikamma National Park, Marine Protected Area ____________________________ 6 2.1.1. Background _________________________________________________________ 6 2.1.2. Climate and oceanography _____________________________________________ 7 2.1.3. Significance of the study area ___________________________________________ 8 2.1.4. Map and site characteristics ____________________________________________ 9 2.1.5. Tsitsikamma species classification ______________________________________ 11 2.2. Sheffield Beach ________________________________________________________ 18 2.2.1. Background ________________________________________________________ 18 2.2.2. Climate and oceanography ____________________________________________ 19 2.2.3. Significance of the study area __________________________________________ 20 2.2.4. Map and site characteristics ___________________________________________ 21 2.2.5. Sheffield Beach species classification ____________________________________ 23 3. CHAPTER 3: A COMPARISON OF FOOD WEB STRUCTURES OF THE INTERTIDAL ROCKY SHORE USING STABLE ISOTOPES ________________________________________________ 29 3.1. Introduction ___________________________________________________________ 29 3.2. Materials & Methods ___________________________________________________ 31 3.2.1. Field survey and sample collection ______________________________________ 31 3.2.2. Laboratory preparation _______________________________________________ 32 3.2.3. Stable isotope analysis _______________________________________________ 32 3.2.4. Statistical analysis ___________________________________________________ 33 3.2.4.1. Stable isotope signatures__________________________________________ 33 pg. ii 3.2.4.2. Trophic level and food chains ______________________________________ 34 3.2.4.3. Group assessments according to functional trophic groups _______________ 34 3.3. Results _______________________________________________________________ 35 3.3.1. Stable isotope signatures _____________________________________________ 35 3.3.2. Trophic level and food chains __________________________________________ 39 3.3.3. Group assessments according to functional trophic groups __________________ 43 3.4. Discussion ____________________________________________________________ 45 3.4.1. Stable isotope signatures _____________________________________________ 45 3.4.2. Trophic level and food chains __________________________________________ 46 3.4.3. Group assessments according to functional trophic groups __________________ 49 3.5. Conclusions ___________________________________________________________ 55 4. CHAPTER 4: TROPHIC MAGNIFICATION OF METALS AND ORGANOCHLORINE PESTICIDES IN INTERTIDAL ORGANISMS FROM TWO ROCKY SHORES ALONG THE SOUTH AFRICAN COASTLINE _________________________________________________________________ 56 4.1. Introduction ___________________________________________________________ 56 4.1.1. Metals ____________________________________________________________ 57 4.1.2. Organochlorine pesticides ____________________________________________ 57 4.1.3. Trophic magnification factors __________________________________________ 58 4.2. Materials & Methods ___________________________________________________ 59 4.2.1. Field survey and sample collection ______________________________________ 59 4.2.2. Laboratory analysis __________________________________________________ 59 4.2.2.1. Metals ________________________________________________________ 60 4.2.2.2. Organochlorine pesticides _________________________________________ 62 4.2.2.3. Trophic magnification factors ______________________________________ 64 4.2.3. Statistical analysis ___________________________________________________ 64 4.3. Results _______________________________________________________________ 65 4.3.1. Metals ____________________________________________________________ 65 4.3.2. Organochlorine pesticides ____________________________________________ 69 4.3.3. Trophic magnification factors __________________________________________ 72 4.3.3.1. Metals ________________________________________________________ 72 4.3.3.2. Organochlorine pesticides _________________________________________ 74 4.4. Discussion ____________________________________________________________ 75 4.4.1. Metals ____________________________________________________________ 75 4.4.2. Organochlorine pesticides ____________________________________________ 77 4.4.3. Trophic magnification factors __________________________________________ 79 4.5. Conclusions ___________________________________________________________ 80 5. CHAPTER 5: CONCLUSIONS & RECOMMENDATIONS _____________________________ 82 pg. iii 5.1. General conclusions _____________________________________________________ 82 5.2. Recommendations ______________________________________________________ 84 References __________________________________________________________________ 85 Appendix A ________________________________________________________________ 102 Appendix B ________________________________________________________________ 104 pg. iv Summary Globally, of all the services and functions that ecological systems provide to human welfare, ± 63 % comes from the marine domain. Pollution of the ocean by means of metals and organochlorine pesticides pose a great threat to the biodiversity of intertidal rocky shores, especially sedentary filter-feeders since they are well known to accumulate a wide range of metals in their soft tissues, as well as to consumers of these species. Past research focused on the use of bio-indicator species to determine concentrations of compounds found within the environment. This hinders the comparison of uptake and transfer between species and results in a knowledge gap in terms of most intertidal rocky shore food webs and species. By examining sites that are as near as possible to a natural