The Marine Microbial Food Web: Competition and Defence as Shaping Forces from Ecosystem to Genes

by Tron Frede Thingstad

Overview

An authoritative and up-to-date exploration of how the competition-defence trade-off has shaped the marine microbial food web

In The Marine Microbial Food Web: Competition and Defence as Shaping Forces from Ecosystem to Genes, distinguished researcher Tron Frede Thingstad delivers an insightful and practical discussion of the microbial portion of the ocean’s food web. The author describes how specific factors, including evolution, biodiversity, organism life strategies, genome organization, biogeochemistry, food web structure, and population dynamics, can be understood as the consequences of the balance between competition and defence.

Using modular idealized mathematical models developed from classical Lotka-Volterra formulations, the book describes models that explain the balance between production and consumption of organic material in the photic zone and the potential for export to the ocean’s interior. It also explains how the models are relevant to contemporary climate change and a variety of other modern applications.

Readers will also find:

• A thorough explanation of why the pathogenicity of many “L-strategists” probably originated as coincidental evolution from originally evolved mechanisms for predator defence
• Comprehensive explorations of the role of the marine microbial food web in ocean biogeochemistry and production
• Practical discussions of simple mathematical models of competition, defence, trade-off, and fitness
• Fulsome treatments of a wide range of organization levels, including individual cells and larger communities of organisms

Perfect for researchers, students, and instructors of marine ecology, marine microbiology, and microbial oceanography, The Marine Microbial Food Web will also prove invaluable to limnologists, oceanographers, and students with an interest in applied mathematics.

Product Details

ISBN-13:	9781394251629
Publisher:	Wiley
Publication date:	07/21/2025
Pages:	240
Product dimensions:	7.20(w) x 10.10(h) x 0.70(d)

About the Author

Tron Frede Thingstad works in the Department of Biological Sciences at the University of Bergen in Norway. He is a renowned scientist in the field of marine microbial ecology and is the co-author of the award-winning Microbial Loop paper published in 1983. His work focuses on combining the flagellate, diatom, and microbial food chains into the microbial food web.

Table of Contents

About the Author ix

Preface xi

About the Companion Website xiii

1 Setting the Scene 1

1.1 The Physical and Chemical Environment of the MMFW 2

1.2 Competitive and Defensive Characteristics of Biological Actors in the MMFW 9

1.2.1 Prokaryotes 11

1.2.2 Protists 12

1.2.2.1 Flagellates 13

1.2.2.2 Diatoms 16

1.2.2.3 Ciliates 18

1.2.3 Metazoan Top Predators on the MMFW 19

1.2.3.1 Copepods 19

1.2.3.2 Euphausiids (Krill) 20

1.2.3.3 Appendicularians 21

1.2.3.4 Rotifers 21

1.2.4 Viruses 21

1.3 New Methods and New Concepts: Paradigm Shifts in Our Understanding of the Mmfw 23

References 28

2 Control Mechanism in Food Chains and Food Webs 37

2.1 Top-Down and Bottom-Up Control in Food Chain 37

2.2 Biomass Versus Growth Rate Limitation 38

2.3 New, Regenerated, and Export Production. What Determines N T—40

2.4 Using an Idealized Mathematical Model to Illustrate the Effects of Food Chain Closure, Stability, Recycling, Defence, Fitness, and Trade-Off 42

2.4.1 Properties of the Steady State 43

2.4.2 Food Web Closure 44

2.4.3 Biomasses and Mass Transfer Rates Scale Differently with Nutrient Content N T 45

2.4.4 Transients and Stability 45

2.5 Fitness and Trade-Off 47

2.6 Monod and Droop Models for Microbial Growth 48

2.7 Competition and Coexistence 50

2.7.1 Bottom-Up-Driven Coexistence 50

2.7.2 Top-Down-Driven Coexistence 50

2.7.3 Pentagon Structures 54

2.8 KtW as a Factor in the Evolution of Present-Day MMFW 55

References 57

3 The Microscale: Microbial Movement and Encounters 59

3.1 α-Parameters and Encounter Kernels 60

3.1.1 What Is the Secret Behind the Diatom Success? 65

3.1.2 Predator and Prey Interactions 66

3.2 Temperature Sensitivity of the MMFW 67

References 68

4 MinMod, a Minimum Model for the MMFW 71

4.1 Model Structure and Philosophy 72

4.2 Model Behaviour 73

4.2.1 Food Web Closure, Characteristic Time Scales and the Difference Between Drivers and Variables 73

4.2.2 The Cascading Effect from Copepods 74

4.2.3 Bacteria–Diatom Balance and Competition for Mineral Nutrients 75

4.3 The Mathematical Formulation 77

4.3.1 The Steady States 81

4.3.1.1 Different States According to Diatom Status 81

4.3.1.2 Steady States with C-Limited Bacteria 83

4.3.2 The Transients 84

4.4 The Importance of Model ‘Transparency’ 85

References 86

5 Prokaryote Diversity and Flux Partitioning 87

5.1 On Fitness, Species Dominance and Evolutionary Stable Communities 90

5.2 The Structuring Effect of Prokaryote Predator Defence 92

5.3 The Structuring Effect of Defence Against Viruses 94

5.3.1 Virus Abundance and Flux Partitioning 95

5.3.2 Viruses, Diversity and Flux Partitioning 103

5.3.3 Host-Virus Arms Races and Experimental Evolution 107

5.4 Species and Strain Diversity, and Flux Partitioning in a One-Species Host-Virus-Predator System 111

5.4.1 Diversity, and Flux Partitioning in a Mixed Prokaryote Community 116

5.5 A Summarizing Hypothesis for How Trade-offs Determines Prokaryote Diversity 125

References 126

6 The Role of Competition and Defence Microbial Genome Organization 131

6.1 Prokaryote Species in Natural Habitats Are not Clonal 131

6.2 An Enigmatic Outlier? The Huge Genome of Dinoflagellates 133

References 134

7 Element Cycles and Ecological Stoichiometry of the MMFW 137

7.1 Ocean Nutrient Content and N : P Ratio 138

7.2 The Si-Cycle 139

7.3 The C-Cycle 140

7.4 Genetic Consequences of Nutrient Limitation 143

References 144

8 Basin Scale Drivers of the MMFW 147

8.1 The Arctic 148

8.1.1 Physical Conditions 148

8.1.2 The Arctic Microbial Food Web 149

8.2 The Mediterranean Sea 152

8.2.1 Circulation and Oligotrophication 152

8.2.2 Why Is the Mediterranean P-Limited? 153

8.2.3 Using the Oligotrophication Gradient to Explore the Pelagic Carbon Cycle 154

8.3 Iron Limitation and HNLC Regions 158

References 160

9 MMFW in the Ocean’s Interior 165

9.1 Missing Energy Source or Technical Measurement Problems? 166

9.2 Protistan Predators in the Ocean’s Interior 169

9.3 Prokaryote Diversity and Viruses in the Aphotic Ocean 170

9.4 Connections to the Upper Part of the Pelagic Food Web 171

References 173

10 Power Laws and Fractal Properties 175

10.1 Equal Mass in Each Decadal Size Class in the Food Chain? 176

10.2 Size and Metabolic Rates 177

References 179

11 Applied Aspects 181

11.1 Marine Pathogens, A Product of Coincidental Evolution? 181

11.2 Bioremediation 183

11.3 Eutrophication 185

11.3.1 Food Web Effects: The Example of Shallow Lake Restoration 185

11.3.2 Coastal Eutrophication. The Interplay Between Land Use, Runoff and Hydrography 186

11.3.3 Climate Change 189

References 193

12 Some Aspects of MMFW That Are Not Included in MinMod 199

12.1 Complications in the Left Pentagon 199

12.1.1 Mixotroph Protists 199

12.1.2 Picoautotrophs 200

12.1.3 Coccolithophores 201

12.2 Complications in the Right Pentagon 201

12.2.1 Dinoflagellates 201

12.3 Alternative Pathways? Bypass and Tunnelling 202

References 202

13 Other Perspectives 205

13.1 Similarities and Differences in Terrestrial Systems 205

13.2 A Final Comment: Competition and Defence from an Anthropocentric Perspective 207

References 208

Appendix 211

Index 213