The Ecology of Tropical Lakes and Rivers A. I. Payne Coventry {Lanchester) Polytechnic JOHN WILEY & SONS Chichester New York Toronto Brisbane Singapore
Contents 1 INTRODUCTION 1 2 THE RIVER ENVIRONMENT 4 2.1 Characteristics of the Water 4. 1 The Concentration of Surface Waters 4.2* The Measurement of Ionic Concentration.... 5.3 Bicarbonate and Carbonate 5.4 Concentration and Composition of Tropical and Temperate Waters 7.5 Sources of Major Chemical Components 7.6 Possible Role of Rain, Rocks, and Evaporation in Determining the Composition of Tropical River Water.... 9 2.2 Water and Land in a River Basin 11 2.2.1 Soil and Vegetation 11 2.2.2 Swamps, Floodplains, and Phytoplankton.... 13 2.2.3 The Influence of Animals 14 2.3 Suspended Materials......... 16 2.4 Variability of Tropical Rivers 17 2.4.1 Geographical 17 2.4.2 Seasonal 20 THE LAKE ENVIRONMENT 23 3.1 Characteristics of Lakes 23 3.1.1 Size and Formation 23 3.1.2 Water Loss and Gain 23 3.1.3 High-altitude Lakes 25 3.1.4 General Distribution 25 3.2 Hydrology and Water Budgets 25 3.2.1 Routes of Gain and Loss 25 3.2.2 Periodic Changes 27 3.2.3 Seasonal Changes 27 3.3 Chemical Environment......... 29 3.3.1 Ionic Concentration 29 3.3.2 Ionic Composition 31 3.4 Classification of Lakes 33 3.5 Stratification and its Effects 35 3.5.1 General Features 35 3.5.2 Effect on Physical and Chemical Factors 38 3.5.3 Multiple Thermoclines 43 3.5.4 Importance of Mixing 46 3.5.5 Shallow Lakes 47
VI 4 COMMUNITY STRUCTURE 50 4.1 Basic Organization 50 4.2 Types and Distribution of Organisms in Aquatic Communities. 52 4.3 Structure in Lakes and Rivers 57 4.4 Qualitative and Quantitative Considerations..... 57 4.5 The Phytoplankton 58 4.5.1 Algae Large and Small 58 4.5.2 Composition 58 (a) Bacillariophyta 58 (b) Chlorophyta 60 (c) Dinophyta 60 (d) Cyanobacteria (Cyanophyta) 60 (e) Others 61 4.5.3 Weight and Numbers 62 (a) Sampling 62 (b) How much Phytoplankton in tropical waters?... 64 4.5.4 Maintaining a Position 65 4.6 Zooplankton 68 4.b. 1 Composition and Characteristics...... 68 4.6.2 Feeding 70 4.6.3 Reproduction 71 4.6.4 Weight and Numbers 72 (a) Sampling 72 (b) Zooplankton biomass in the tropics 72 4.6.5 Vertical Distribution and Diurnal Migration.... 73 4.7 The Benthos 75 4.7.1 Composition 75 4.7.2 Feeding 79 4.7.3 Sampling 83 4.7.4 Biomass and Assemblages in Natural and Man-made Lakes. 84 4.7.5 Biomass and Assemblages in Flowing Waters.... 88 4.8 The Nekton 90 4.8.1 Composition 90 4.8.2 River Fishes 98 4.8.3 Fish in Lakes 105 4.9 Littoral and Surface Vegetation 108 4.9.1 Composition '.. 108 4.9.2 Littoral Vegetation '.. Ill 4.9.3 Plants of the Water Surface 114 4.9.4 Vegetation of Rivers 114 4.9.5 Biomass 118 4.10 Community Structure and the Distribution of Biomass... 120 General Reading 121 5 COMMUNITY DYNAMICS 123 5.1 The Basis of Production 123 5.2 Primary Production 125 5.2.1 Light 125 5.2.2 The Measurement of Primary Production.... 127 (a) Light and dark bottle oxygen method 127 (b) Light and dark 14 C method 129 (c) Oxygen flux in a whole water body 130 (d) The use of satellite photography 131
5.2.3 Patterns of Productivity 131 (a) Lakes 131 (b) Rivers 140 (c) Swamps and marginal vegetation 143 5.2.4 Nutrient Recycling 146 (a) Which nutrients limit photosynthesis?.... 146 (b) The distribution of nutrients 149 5.3 Microbial Activity and Decomposition 153 5.4 Secondary Production 156 5.4.1 Feeding Relationships 156 5.4.2 Some Effects of Grazing 158 5.4.3 Rates of Production 159 (a) Zooplankton......... 159 (b) Benthic animals 160 (c) Fish 162 5.5 Energy Flow Within the Ecosystem 164 General Reading. 168 Vll SEASONALITY 169 6.1 Are There Seasons in the Tropics?....... 169 6.2 The Phenology of Production 170 6.3 Seasonal Versus Daily Changes in Production.... 176 6.4 Animal Periodicity 178 6.4.1 Seasonal Factors in Flowing Waters..... 179 6.4.2 Feeding and Food Availability 180 6.4.3 Reproduction 182 (a) Rivers 182 (b) Lakes 186 7 DIVERSITY AND EVOLUTION 188 7.1 How Diverse are Communities in Tropical Fresh Waters?.. 188 7.1.1 General Considerations 188 7.1.2 The Producers 189 7.1.3 The Zooplankton 191 7.1.4 Benthic Organisms. 192 7.1.5 Some are Less Diverse Than Others 196 7.2 The Meaning of Diversity........ 197 7.3 The Relationship of Diversity to Production and Time... 201 7.4 Coexistence in a Crowded Environment 207 7.5 Sources of Diversity 219 7.6 Stability and Change 223 General Reading 231 THE USE AND CONTROL OF AQUATIC BIOLOGICAL RESOURCES 232 8.1 Man and Water 232 8.2 Fisheries 234 8.2.1 The Basis of Production and the Prediction of Yields.. 234 8.2.2 Fishery Management 238 8.2.3 The Introduction of Exotic Species 246 8.3 Aquaculture 248
Vlll 8.4 Pollution 8.5 Health 259 265 General Reading 270 BIBLIOGRAPHY 271 INDEX 290