Ecophysiological Studies of Three Ulva Species That Are Used As Both Biofilters and Feed on South African Abalone Farms
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The copyright of this thesis vests in the author. No quotation from it or information derived from it is to be published without full acknowledgementTown of the source. The thesis is to be used for private study or non- commercial research purposes only. Cape Published by the University ofof Cape Town (UCT) in terms of the non-exclusive license granted to UCT by the author. University ECOPHYSIOLOGICAL STUDIES OF THREE SOUTH AFRICAN ULVA SPECIES FROM INTEGRATED SEAWEED/ABALONE AQUACULTURE AND NATURAL POPULATIONS By Diina Shuuluka Submitted in fulfilment of the requirements for the Doctor of Philosophy in the Faculty of Science at the University of Cape Town February 2011 Supervisor: Prof. John J. Bolton, University of Cape Town Co-Supervisor: Associate Prof. Robert J. Anderson, University of Cape Town and UniversityDepartment of Agriculture, of FisheriesCape and TownForestry, South Africa DECLARATION I declare that this thesis is my own, unaided work except for amino acid analysis that was carried out by the University of Cape Town, Cell and Molecular Department, Carbon and Nitrogen analysis that was carried out by the University of Cape Town, Chemistry Department and elemental and heavy metals that was carried out by the commercial feed laboratory (BEMLAB, analysis laboratory, Stellenbosch). This thesis has not been submitted in this or any form to another university. Where use has been made of the research of others, it has been duly acknowledged in the text. Experimental work discussed in this thesis was carried out under the supervision of Prof. J. J. Bolton of the Department of Botany, University of Cape Town and Assoc. Prof R. J. Anderson of UCT/Department of Agriculture, Fishereies and Foresty. Signature removed ____________________ Diina Shuuluka Department of Botany, University of Cape Town February 2011 University of Cape Town II DEDICATION This thesis is dedicated to my parents and grandmother For their love and support University of Cape Town III TABLE OF CONTENTS TITLE PAGE ..........................................................................................................................I DECLARATION ………………………………………………………………....................II DEDICATION ………………………………………………………………......................III TABLE OF CONTENTS......................................................................................................IV LIST OF FIGURES …………………………………………………….………….............IX LIST OF TABLES ………………………………………………………………...............XV PREFACE …………………………………………………………….............................XVII ACKNOWLEDGEMENTS............................................................................................XVIII ABSTRACT .........................................................................................................................XX Chapter 1 ........................................................................................................................... 1 General Introduction ........................................................................................................... 1 1.1 The genus Ulva .......................................................................................................... 1 1.2. The biogeographical distribution of Ulva ................................................................ 3 1.3 Life history of Ulva ................................................................................................. 5 1.4 Ulva mariculture in South Africa ............................................................................ 8 1.5 Ulva as feed for aquatic animals ................................................................................. 10 1.6 Factors affecting Ulva growth ............................................................................... 11 1.6.1 Salinity ............................................................................................................... 12 1.6.2 Light ................................................................................................................... 13 1.6.3 Light quality ....................................................................................................... 14 1.6.4 Temperature ....................................................................................................... 15 1.6.5 Nitrogen ............................................................................................................. 18 1.6.6 Phosphorus ......................................................................................................... 20 1.7 Pigments ................................................................................................................ 20 1.8 PhotosynthesisUniversity ................................ of................................ Cape Town....................................... 22 1.10 Accumulation of metals ......................................................................................... 25 1.11 Amino acid composition ........................................................................................ 27 1.12 Protein content in Ulva and nitrogen to protein conversion factor ........................ 28 1.13 Effect of epiphytes and diseases on Ulva cultivation ............................................ 30 1.14 Background of the study ........................................................................................ 31 1.15 Collection sites and Ulva species used in the research project .............................. 35 1.16 Aims of this study .................................................................................................. 37 Chapter 2 ............................................................................................................................. 41 Effects of irradiance, light quality, temperature, salinity and nutrients on the growth rate of U. rigida, U. capensis and U. lactuca in culture .................................................................. 41 IV 2.1 Introduction ........................................................................................................... 41 2.2 Materials and Methods .......................................................................................... 48 2.2.1 Plant collection ...................................................................................................... 48 2.2.2 Culture methods ................................................................................................. 49 2.2.2.1 Irradiance, salinity, temperature and light quality experiments ......................... 49 2.2.2.2 Nitrogen and phosphate experiments ................................................................. 50 2.2.2.3 Growth measurements ...................................................................................... 50 2.2.3 Statistical analysis .............................................................................................. 51 2.3 Results ................................................................................................................... 51 2.3.1 Effect of salinity on growth ............................................................................... 51 2.3.2 Effect of irradiance on growth ........................................................................... 53 2.3.3 Effect of light quality on growth ........................................................................ 54 2.3.4 Effect of temperature on growth ........................................................................ 55 2.3.5 Effect of nutrient enrichment on growth ............................................................ 56 2.3.6 Optimum growth parameters ............................................................................. 59 2.4 Discussion .............................................................................................................. 60 Chapter 3 ............................................................................................................................. 71 Seasonal variation in photosynthetic production in intertidal Ulva capensis and Ulva rigida from the west coast of South Africa ..................................................................................... 71 3.1 Introduction ........................................................................................................... 71 3.2 Materials and Methods .......................................................................................... 73 3.2.1 Collecting site .................................................................................................... 73 3.2.2 Tissue preparation and photosynthesis measurements ...................................... 74 3.2.3 StatisticalUniversity analysis.............................................................................................. of Cape Town 76 3.3 Results ................................................................................................................... 77 3.4 Discussion .............................................................................................................. 80 Chapter 4 ............................................................................................................................. 83 Productivity and species dominance of Ulva in outdoor culture raceways at Irvin & Johnson abalone farm ........................................................................................................... 83 4.1 Introduction ..........................................................................................................