Life in the Open Ocean

Joseph J. Torres is Emeritus Professor of Marine Science, College of Marine Science, University of South Florida, St Petersburg, FL, USA. He is an internationally-renowned marine biologist with research interests in the physiological ecology of the deep- and open-oceanic realms. Thomas G. Bailey is retired director of NOAA’s Caribbean Marine Research Center following a long career in deep-ocean science at the Harbor Branch Oceanographic Institution as head of the Department of Zooplankton Ecology. He is a highly respected in-situ marine scientist known for innovative techniques in capturing and experimenting with delicate sea creatures at great depth.

Preface xviii

Acknowledgments xx

1 Physics and the Physical Environment 1

The Vastness of the Open Ocean 2

The Properties of Water 2

Density 4

Viscosity 5

Reynolds Number 6

Drag 7

Temperature 8

The Oceans and Ocean Basins 9

Ocean Circulation 10

Surface Currents: Ocean Gyres and Geostrophic Flow 10

Ocean Gyres and Geostrophic Flow 15

Upwelling 16

Deep-Ocean Circulation 16

Water Masses 18

Oxygen 24

Pressure 24

Sound 26

Light 29

Absorption and Scattering 31

Traditional Depth Zones in the Ocean 33

Concluding Thoughts 34

References 35

2 Physiological Accommodation to Environmental Challenges 36

Temperature 37

Terms 38

Temperature Effects on Survival: The Tolerance Polygon 39

Temperature Effects on Rate Processes – The Q10 Approximation 41

Patterns of Thermal Acclimation 43

Climatic Adaptation in Ectotherms 44

Temperature Compensation via Changes in Enzyme Concentration: The Quantitative Strategy for Short-term Change 47

Compensation via Changes in Enzyme Quality – Isozymes, Allozymes, and Temperature Adaptation 47

What Properties of Enzymes Can Be Changed? 51

Lipids and Temperature 53

A Membrane Primer 54

Pressure 59

Early Work 60

Later Work 61

Whole Animal Work 63

Molecular Mechanisms of Adaptation to Pressure 64

Pressure and Membranes 68

Oxygen 69

Severity of Oxygen Minima, “Dead Zones,” and the Intertidal 71

Adaptations to Oxygen Minima 71

The Aerobic Strategy 71

Salinity 75

Depth 77

Concluding Thoughts 83

References 84

3 The Cnidaria 89

Introduction 89

Classification 89

History 89

Classification Schemes 90

Phylum Cnidaria 91

Subphylum Medusozoa 91

Subphylum Anthozoa 91

Subphylum Myxozoa 91

The Hydromedusae 92

Morphology Basics 92

Morphological Detail and Life Histories 95

The Scyphomedusae 99

Basic Characteristics 99

Morphological Detail and Life Histories 101

General 101

Coronatae 101

Semaeostomae 102

Rhizostomae 104

The Cubomedusae 105

Foraging Strategies 105

General Considerations 106

The Cnidae 107

Venoms 108

Interaction with Prey 109

Direct Interception 110

Encounter Zone 110

The Model 114

Swimming and Hunting Behavior 115

Water Flow and Swimming 115

Attraction Between Predator and Prey 116

Diets, Feeding Rates, and Impacts on Prey Populations 117

Rogue Hydroids: Predatory Polyps in the Midwater 119

Feeding in the Cubomedusae 120

Locomotion 121

The Mesoglea 123

Nerve Nets and Nervous Control of Swimming 124

Senses and Sensory Mechanisms 125

The Siphonophores 127

Terminology and Affinities of Siphonophore “Persons” 128

Whole Animal Organization 134

Life Histories 137

The Siphonophore Conundrum 137

Feeding 138

Fishing Behavior 138

Digestion 139

Diets and Selectivity 139

Ecological Importance 141

Locomotion 141

Buoyancy 143

Vertical Distribution 144

Diurnal Vertical Migration 146

Geographical Distribution 147

Organization and Sensory Mechanisms 147

Epithelial Conduction vs. Neural Conduction 148

The Cnidaria Formerly Known as Chondrophora 150

Classification 150

Characteristics of the Chondrophoran Medusa 151

Evolution Within the Chondrophora 151

Feeding in the Chondrophora 151

Locomotion 151

References 153

4 The Ctenophora 159

Introduction 159

Classification 159

History 159

Classification Schemes 160

Ctenophore Basics 161

Morphology 162

Cydippida 162

Lobata 165

Cestida 168

Beroida 168

Platyctenida 168

Ganeshida 171

Thalassocalycida 173

Foraging Strategies 173

General Considerations 173

Interaction with Prey 173

The Cydippids 173

The Lobates 174

The Cestids 175

The Beroids 175

The Platyctenids 178

The Ganeshids 178

The Thalassocalycids 178

Specialists 178

Diet, Feeding Rates, and Impacts on Prey Populations 178

Ctenophores as Invasive Species 179

Digestion 181

Nerves and Sense Organs: Coordination and Conduction 181

Locomotion 182

Distribution 185

Ctenophores and Evolution 186

References 189

5 The Nemertea 192

Introduction 192

Classification 193

History 193

Of Germ Layers and Body Cavities 194

Hydrostatic Skeletons 197

Classification 200

Morphology 200

Proboscis Apparatus 202

The Pelagic Body Form and Locomotion 204

Color 205

Nervous System 205

Sense Organs 207

Circulatory System 207

Excretory System 209

Digestive System 211

Reproduction 213

Development 215

Foraging Strategies 215

Vertical and Geographic Distributions 215

References 217

6 The Annelida 219

Introduction 219

History 221

Classification 222

Phylum Annelida 224

Class Polychaeta 224

Subclass Echiura 225

Subclass Errantia 226

Class Clitellata 226

Subclass Oligochaeta 227

Subclass Hirudinea 228

The Pelagic Polychaetes 228

Polychaete Subclass Errantia 229

Order Phyllodocida 229

Polychaete Subclass Sedentaria 229

Order Terebellida 231

Morphology 231

General 231

External Anatomy 233

The Head Region 234

The Trunk or Metastomial Region 236

Internal Anatomy 239

Excretory System 241

Pelagic Species 243

The Nervous System 244

Sense Organs 244

Circulatory System 246

Pelagic Species 249

Gas Exchange 249

Pelagic Species 249

Digestive System 250

Reproduction 251

Epitoky 252

Synchronicity 252

The Pelagic Species 254

Tomopteris 254

Alciopini and Lopadorrynchidae 254

Development 255

Locomotion 255

Foraging Strategies 256

The Hunters 256

Diets 258

The Suspension Feeders 258

Poeobiidae, Chaetopteridae 259

Distributions 259

Geographical 259

Vertical 267

Bioluminescence 267

References 268

7 The Crustacea 273

Introduction 273

Arthropod Classification 273

History 273

Subphylum Crustacea 276

Subphylum Hexapoda 277

Subphylum Myriapoda 277

Subphylum Chelicerata 277

Panarthropoda Phyla 277

Phylum Onychophora 277

Phylum Tardigrada 277

Synopsis of Universal Arthropod Characteristics 278

The Crustacea 280

Characteristics 281

Classification 281

Subphylum Crustacea 283

Class Remipedia 283

Class Cephalocarida 283

Class Branchiopoda 283

Class Copepoda 283

Class Thecostraca 283

Class Tantulocarida 283

Class Mystacocarida 283

Class Branchiura 283

Class Pentastomida 284

Class Ostracoda 284

Class Malacostraca 284

Subclass Phyllocarida 284

Subclass Hoplocarida 284

Subclass Eumalacostraca 284

Crustacean Systems 292

Integument and Molting 292

Integument 292

Molting 293

Joints and Appendages 296

Joints 296

Appendages 297

Excretory System 297

Extra-renal Mechanisms 301

How the System Works 303

Nitrogen Excretion 303

The Nervous System and Sensory Mechanisms 303

The Central Nervous System 303

Sensory Modalities 305

Photoreception 305

Mechanoreception 308

Chemoreception 310

Circulatory and Respiratory Systems 311

Circulation and Oxygen Transport in the Blood: Hemocyanin 317

Digestive System 318

Basic Development 319

The Micronektonic Crustacea 319

The Pelagic Eucarida 321

Order Euphausiacea 321

Ecological Factors 339

Order Decapoda 346

Infraorder Anomura; Superfamily Galatheoidea; Family Munididae; Genera Pleuroncodes, Munida, and Cervimunida 378

Order Amphionidacea 379

Superorder Peracarida 380

Orders Lophogastrida and Mysida 380

Order Amphipoda 397

Cameo Players 420

References 424

8 The Mollusca 439

Introduction 439

Classification 440

History 440

The Pelagic Molluscs 441

Phylum Mollusca 442

Class Caudofoveata 442

Class Solenogastres 442

Class Monoplacophora 442

Class Polyplacophora 442

Class Scaphopoda 443

Class Bivalvia 444

Class Gastropoda 445

Class Cephalopoda 445

Body Organization 445

The Gastropoda 445

Classification 445

Class Gastropoda 449

Classification Below Subclass Given for Pelagic Species Only 449

Gastropod Systems and Structures 451

The Digestive Tract 451

Circulation 454

Respiration 457

Excretion 461

Shell Formation 464

The Nervous System 466

Sensory Mechanisms 469

The Pelagic Gastropods: Anatomy and Habits 475

The Janthinid Snails 475

The Heteropods 477

The Pteropods 491

Order Pteropoda 492

The Nudibranchs 516

The Cephalopoda 525

Classification 528

Basic Anatomy of the Major Cephalopod Groups 529

General 529

The Nautilida 529

The Sepiida and Spirulida 531

The Myopsida and Oegopsida 532

The Octopodiformes 536

Cephalopod Systems 540

Feeding and Digestion 540

Circulation 544

Gas Exchange 544

Excretion 549

Nervous System and Sensory Mechanisms 552

Locomotion and Buoyancy 569

Life Histories 575

Reproduction and Development 578

Vertical Distribution and Migration 582

Geographic Distribution 588

References 589

9 The Chordata 603

Introduction 603

Deuterostomes and the Phylogenetic Toolkit 604

Classification 607

Subphylum Tunicata 607

Class Ascidiacea (2935) 607

Class Appendicularia (68) 607

Class Thaliacea (78) 607

Basic Anatomy and Life History 609

The Ascidians 609

The Pyrosomes 610

The Salps 613

The Doliolids 618

The Appendicularia 625

The Appendicularian House 629

Tunicate Systems 634

Locomotion and Buoyancy 634

Pyrosomes 634

Salps 635

Doliolids 637

Appendicularia 638

Nervous Systems and Sensory Mechanisms 638

Pyrosomes 639

Doliolids 639

Salps 641

Appendicularia 643

Gas Exchange, Circulation, and Excretion 645

Trophic Role 647

Bioluminescence 653

Predators, Parasites and Other Interactions 654

Geographic and Vertical Distributions 656

References 660

10 The Fishes 669

Introduction 669

The Deep-Sea Groups 672

A Brief History of Fishes 674

The Jawless Fishes 674

The Jawed Fishes 676

Teleosts 676

Elasmobranchs 677

Holocephali 677

The Classes of Living Fishes 678

Class Myxini 678

Class Petromyzonti 679

Class Elasmobranchii 682

Class Holocephali 691

Class Coelacanthi 693

Class Dipneusti 695

Class Cladistii 695

Class Actinopterygii 695

Subclass Chondrostei 696

Subclass Holostei 696

Subclass Teleostei 696

Fish Systems 758

Basic Anatomy 758

External Features and Terms 758

Skull and Skeleton 758

Feeding and Digestion 760

Food Acquisition, the Three Dominant Modes: Ramming, Sucking, and Biting 760

Food Sorting: The “Pharyngeal Jaws” 764

Digestion: The Alimentary Canal 765

Circulation, Respiration, and Excretion 767

Circulation 767

Gas-Exchange in the Teleosts and Elasmobranchs 771

Unidirectional Flow and Countercurrent Exchange: Maximizing the Concentration Gradient 774

Blood and Oxygen at the Respiratory Surface 775

CO2 Transport–Far Different from O2 780

The Bohr and Haldane Effects 781

Secretion of Gases into the Swimbladder of Fishes 782

Nitrogen Excretion 785

Osmotic and Ionic Regulation 785

Introduction 785

Osmosis and Diffusion 787

The gills 790

Esophagus 791

Stomach 793

Intestine 793

Locomotion 793

Musculature 793

Red and White Muscle 795

Drag and Swimming Costs 796

Maximum Swim Speeds 797

Endothermy 799

Warm-Brained Billfishes 799

Swimming in Mesopelagic Fishes 801

Buoyancy 801

The Nervous System 804

Anatomy and Basics 804

The Brain 806

Cranial Nerves 807

Sensory Mechanisms 809

Sensory Modalities 809

Photoreception 811

Mechanoreception 815

The Inner Ear and Sound Reception 818

Electroreception 820

Chemoreception: Olfaction and Gustation 822

Camouflage, Bioluminescence, Photophores 824

Camouflage 824

Bioluminescence and Photophores 824

References 829

11 Communities 845

Introduction 845

The Gulf of Mexico 846

The Northern California Current 847

The Antarctic 852

System Comparisons 858

The Decapods and Mysids 876

The Euphausiids 881

The Myctophids 882

Non-myctophid Fishes 883

The Cephalopods 884

Gelatinous Zooplankton and Amphipods 885

Concluding Observations 887

Physical and Biological Factors that Change 887

Mean Annual Temperature 887

Seasonal Cycling 887

Annual Production 887

Current Patterns 887

References 888

12 Energetics 893

Introduction 893

A Model Energy Budget 894

Digestibility of Biomolecules 896

Energy Value of Biomolecules 897

Measuring Metabolic Rate 898

Oxygen Consumption Rate-Modifying Factors 898

Activity 899

Experimental Protocol 900

Routine Metabolic Rate 900

Animal Size as a Modifier of Metabolism 901

Life History Strategies 902

Metabolism and Composition of Pelagic Species 914

Metabolism of Euphausiids, Decapods, Mysids, and Amphipods 929

Proximate Composition of Pelagic Decapods, Mysids, and Euphausiids 930

Terminology 931

Trends with Depth of Occurrence 931

Seasonal Changes 932

Trends Across Systems 932

Metabolism of Mesopelagic Fishes 933

Proximate Composition of Pelagic Fishes 934

Trends with Depth of Occurrence 934

Trends Across Systems 934

Energy and Life History in the Midwater Fauna 935

Midwater Fishes 936

The Cephalopods 938

Pteropods, Nemerteans, Annelids, Salps, and Pyrosomes 938

The Cnidaria and Ctenophora 939

Conclusions 939

References 940

Appendix A Classification of the Chordata 945

Glossary 959

Index 963