University of Ghana http://ugspace.ug.edu.gh UNIVERSITY OF GHANA ECO-FUNCTIONAL BENTHIC BIODIVERSITY ASSEMBLAGE PATTERNS IN THE GUINEA CURRENT LARGE MARINE ECOSYSTEM A THESIS SUBMITTED TO THE DEPARTMENT OF MARINE & FISHERIES SCIENCES FOR THE DEGREE OF DOCTOR OF PHILOSOPHY BY EMMANUEL LAMPTEY (10074462) IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF A PhD. OCEANOGRAPHY DECEMBER, 2015 University of Ghana http://ugspace.ug.edu.gh i DECLARATION This PhD thesis is original and independent research work conducted under supervision of Dr. George Wiafe, Prof. Elvis Nyarko and Mr. A.K. Armah of the Department of Marine and Fisheries Sciences. This research has not been included in any thesis or dissertation submitted to other institution for a degree, or any other qualifications. Authors whose works were used have been duly referenced/recognised. ………………………… Emmanuel Lamptey (PhD Student) ……………………..…… Dr. G. Wiafe (Principal Supervisor) .....……………………… ………………………… Prof. Elvis Nyarko Mr. A.K. Armah (Supervisor) (Supervisor) University of Ghana http://ugspace.ug.edu.gh ii DEDICATION I dedicate this piece of work to God Almighty and my family. University of Ghana http://ugspace.ug.edu.gh iii ACKNOWLEDGMENT I greatly would like to acknowledge my supervisors, Dr. George Wiafe, Prof. Elvis Nyarko and Mr. A.K. Armah for their immense contribution and support towards the thesis final milestone. I would like to acknowledge the support from my host institution, University of Ghana for some financial support; the Department of Marine & Fisheries Sciences, University of Ghana, for providing me with office and laboratory space. My profound gratitude goes to the Guinea Current Large Marine Ecosystem Programme for the opportunity to be onboard the RV Dr. Fritdjorf Nansen to collect samples; and also to ESL consulting for the opportunity offered me to on board the RV GeoExplorer to collect the epibenthic fauna samples during the West Africa Gas Pipeline Project. I owe a great deal of gratitude to my family for all manner of immeasurable support. Further, to my friends, colleagues, former students, staff and students of Department of Marine and Fisheries Sciences, I would like to express my heartfelt appreciation for the diverse support and encouragements. University of Ghana http://ugspace.ug.edu.gh iv TABLE OF CONTENTS Page ABSTRACT…………………………………………………………………………1 CHAPTER ONE 1.0 GENERAL INTRODUCTION ........................................................................ 4 1.1 Study Objectives and Hypothesis ................................................................... 12 1.2 Study Justification .......................................................................................... 13 1.3 Datasets for the Thesis ................................................................................... 15 1.4 Organization of Thesis ................................................................................... 15 CHAPTER TWO 2.0 LITERATURE REVIEW ............................................................................... 17 2.1 Marine Benthic Biodiversity ......................................................................... 17 2.2 Functional Role of Benthic Communities ...................................................... 20 2.3 Biodiversity Indices and Measurements ........................................................ 23 2.3.1 Diversity Indices ................................................................................ 26 2.3.2 Functional Diversity ........................................................................... 28 2.3.3 Functional Diversity Indices .............................................................. 32 2.3.4 Functional Trait Analysis ................................................................... 37 2.4 Disturbance of Marine Biodiversity ............................................................... 40 2.5 Environmental Drivers of Marine Benthic Diversity ..................................... 46 2.5.1 Spatial and Temporal Patterns of Environmental Drivers ................. 50 2.5.2 Water Depth ....................................................................................... 53 2.5.3 Substrate Types .................................................................................. 54 University of Ghana http://ugspace.ug.edu.gh v 2.5.4 Primary Productivity .......................................................................... 57 2.5.5 Organic Carbon .................................................................................. 58 2.5.6 General Oceanography ....................................................................... 63 2.5.7 The Guinea Current Ecosystem ......................................................... 64 CHAPTER THREE 3.0 MACROBENTHIC FUNCTIONAL TRAIT DIVERSITY AND COMMUNITY STRUCTURE ALONG ENVIRONMENTAL GRADIENT .......... 70 3.1 Introduction ................................................................................................... 70 3.2 Materials and Methods .................................................................................. 76 3.2.1 Study Area ...................................................................................................... 76 3.2.2 Field Sampling ................................................................................... 76 3.2.3 Field Quality Control ......................................................................... 78 3.2.4 Laboratory Processing of Samples ..................................................... 79 3.2.4.1 Taxonomic Identification ........................................... 80 3.2.4.2 Laboratory Analysis of Abiotic Data ......................... 81 3.2.4.3 Analysis of Physical Parameters ................................ 81 3.2.4.4 Chemical Analysis ..................................................... 82 3.2.5 Functional Trait Analysis ................................................................... 84 3.2.5.1 Ecological and Biological Traits ................................ 87 3.2.5.2 Functional Trait Classification and Categorization .... 87 3.3 Statistical Analysis ........................................................................................ 89 3.4 Results ............................................................................................................ 94 3.4.1 Macrobenthic Fauna Community Structure ....................................... 94 3.4.2 Macrobenthic Faunistic Density ........................................................ 98 University of Ghana http://ugspace.ug.edu.gh vi 3.4.3 Dominant Macrobenthic Taxa .......................................................... 100 3.4.4 Spatial Pattern of Sediment Abiotic Variables ................................. 103 3.4.5 Community Structural Analysis ....................................................... 107 3.4.5.1 Community Structure- Environmental Relation ...... 110 3.4.5.2 Functional Trait Richness and Distribution ............. 115 3.4.5.3 Distribution of Most Dominant Functional Traits ... 120 3.4.5.4 Multivariate Structural Analysis of Functional Trai 121 3.4.6 Functional Trait-Environment Interactions ...................................... 123 3.4.6.1 Functional Trait-Environment Model ...................... 126 3.6 Discussion .................................................................................................... 129 3.6.1 Species Composition and Abundance .............................................. 129 3.6.2 Functional Structure and Assemblage Patterns ................................ 131 3.6.3 Functional Trait-Environment Relationship .................................... 134 CHAPTER FOUR 4.0 ...... IMPACT OF DEMERSAL FISH TRAWLING ON THE STRUCTURE AND FUNCTIONAL ASSEMBLAGES OF EPIBENTHIC FAUNA ALONG BATHYMETRIC GRADIENT IN THE GUINEA CURRENT ............................. 140 4.1 Introduction .................................................................................................. 140 4.2 Study Objectives .......................................................................................... 144 4.3 Materials and Methods ................................................................................. 145 4.3.1 Study Area ........................................................................................ 145 4.3.2 Field Sampling ................................................................................. 145 4.3.3 Laboratory Processing of Samples ................................................... 147 4.3.4 Statistical Analysis ........................................................................... 151 University of Ghana http://ugspace.ug.edu.gh vii 4.4 Results .......................................................................................................... 153 4.4.1 Epifauna Composition ...................................................................... 153 4.4.1.1 Comparison of Bathymetric Distribution of Epifauna and Fish Assemblage Structure ...................................................... 156 4.4.2 Pattern of Major Epifaunal Taxa ...................................................... 159 4.4.3 Species Dominance and Pollution Status ......................................... 166 4.4.4 Epifauna Functional Composition .................................................... 177 4.4.4.1 Functional Group Diversity ...................................... 177 4.5 Discussion .................................................................................................... 181 4.5.1 Functional Group Classification .....................................................