Ocean Biogeochemical Dynamics

Jorge L. Sarmiento is Professor of Geosciences at Princeton University. Nicolas Gruber is Associate Professor of Geophysics at the University of California, Los Angeles.

• Preface xi Chapter 1: Introduction 1 1.1 Chemical Composition of the Ocean 1 1.2 Distribution of Chemicals in the Ocean 7 1.3 Chapter Conclusion and Outline of Book 15 Problems 16 Chapter 2: Tracer Conservation and Ocean Transport 19 2.1 Tracer Conservation Equation 19 Advection and Diffusion Components 19 Application to Box Models 22 2.2 Wind-Driven Circulation 23 Equations of Motion 27 Ekman Transport 28 Gyre Circulation 30 2.3 Wind-Driven Circulation in the Stratified Ocean 33 Basic Concepts 34 Ocean Stratification 34 Geostrophic Equations 37 Gyre Circulation with Stratification 37 Insights from the Potential Vorticity Distribution 38 Insights from Tracers 39 Insights from the Thermal Wind Relationship 42 2.4 Deep Ocean Circulation 46 Observations 46 Models 52 Summary of Deep Ocean Circulation 57 2.5 Time-Varying Flows 59 Mesoscale Variability 60 Interannual to Decadal Variability 61 Tropical Variability 61 Extratropical Variability 66 Problems 69 Chapter 3: Air-Sea Interface 73 3.1 Introduction 73 3.2 Gas Solubilities 75 3.3 Gas Exchange 80 Stagnant Film Model 81 Laboratory Studies 83 Field Studies 86 Gas Transfer Velocity Models 89 3.4 Applications 95 Problems 100 Chapter 4: Organic Matter Production 102 4.1 Introduction 102 Nutrient Supply 105 Light 111 Efficiency of the Biological Pump 111 Outline 114 4.2 Ecosystem Processes 115 Nutrients 115 Composition of Organic Matter 115 Limiting Nutrient 117 Paradigm of Surface Ocean Nitrogen Cycling 117 Phytoplankton 123 Classification of Organisms 123 Phytoplankton Distribution and Productivity 128 Modeling Photosynthesis 131 Zooplankton 135 Bacteria 137 4.3 Analysis of Ecosystem Behavior 138 Role of Light Supply 139 Classical Ecosystem Models 142 N-P Model--Bottom-up Limitation 142 N-P-Z Model--Top-Down Limitation 144 Adding the Microbial Loop 146 Multiple Size Class Ecosystem Models 147 The Model 147 Influence of Micronutrients 149 Applications 150 North Pacific versus North Atlantic 152 Oligotrophic Region 155 4.4 A Synthesis 157 The Regeneration Loop 158 The Export Pathway 158 The Role of Iron 160 Conclusions 162 Problems 168 Chapter 5: Organic Matter Export and Remineralization 173 5.1 Introduction 173 Nutrient and Oxygen Distributions 173 Remineralizaton Reactions 178 Preformed and Remineralized Components 179 Dissolved and Particulate Organic Matter 180 Outline 181 5.2 Oxygen 181 Separation of Preformed and Remineralized Components 181 Deep Ocean Oxygen Utilization Rates 182 Thermocline Oxygen Utilization Rates 183 5.3 Nitrogen and Phosphorus 186 Stoichiometric Ratios 186 Phosphate 188 The Nitrogen Cycle 189 N* as a Tracer of Denitrification 189 N* as a Tracer of N2 Fixation 195 The Oceanic Nitrogen Budget 196 Nitrous Oxide 197 5.4 Organic Matter Cycling 200 Particulate Organic Matter 200 Overview 200 Particle Flux 203 The Role of Ballast 206 Particle Remineralization 207 Models of Particle Interactions 209 Dissolved Organic Matter 211 5.5 Models 215 Model Development 215 Sensitivity Studies 217 Applications: Control of Oceanic Oxygen 221 Problems 222 Chapter 6: Remineralization and Burial in the Sediments 227 6.1 Introduction 227 Observations 227 Sediment Properties and Processes 229 Remineralization Reactions 233 6.2 Sediment Diagenesis Models 236 Pore Waters 237 Solids 241 6.3 Remineralization 245 Oxic Sediments 246 Anoxic Sediments 250 Dissolved Organic Carbon 253 6.4 Burial 255 The Substrate 255 The Oxidant 256 Protection by Mineral Adsorption 257 Synthesis 258 6.5 Organic Matter Budget 260 Problems 267 Chapter 7: Silicate Cycle 270 7.1 Introduction 270 Water Column Observations 271 Sediment Observations 271 Outline 278 7.2 Euphotic Zone 278 Diatoms 278 Opal Production and Export 280 7.3 Water Column 285 Opal 286 Silicic Acid 288 7.4 Sediments 295 Opal Dissolution and Burial 295 Opal Chemistry 299 7.5 Conclusion 308 Overview 308 Marine Si Budget 309 Long-Term Homeostasis 311 Problems 313 Chapter 8: Carbon Cycle 318 8.1 Introduction 319 8.2 Inorganic Carbon Chemistry 322 8.3 The Surface Ocean 327 Annual Mean Distribution 327 Physical Processes 328 Biological Processes 331 Vector Diagrams 334 Seasonal Variability 335 Subtropical Gyres 337 North Atlantic 340 North Pacific 341 8.4 Water Column 342 Outline 342 Pump Components 342 The Biological Pumps 345 The Gas Exchange Pump 347 Global Mean 347 Atlantic versus Pacific 349 8.5 Carbon Pumps and Surface Fluxes 352 Problems 355 Chapter 9: Calcium Carbonate Cycle 359 9.1 Introduction 359 9.2 Production 362 Organisms 362 Export Estimates 363 Inorganic-to-Organic Carbon Export Ratio 363 9.3 Water Column Processes 365 CaCO3 Solubility 365 Variations in Saturation State 368 Carbonate Ion Distribution 368 Water Column Dissolution 371 9.4 Diagenesis 374 CaCO3 Dissolution in Sediments 374 Modeling CaCO3 Diagenesis 379 Model Applications 379 Concluding Remarks 384 9.5 Calcium Carbonate Compensation 384 CaCO3 Homeostat 384 CaCO3 Compensation 386 Problems 389 Chapter 10: Carbon Cycle, CO2, and Climate 392 10.1 Introduction 392 Greenhouse Effect 394 Global Warming 396 Outline 398 10.2 The Anthropogenic Perturbation 399 Capacity Constraints 400 Buffering by Dissolved Carbonate 400 Buffering by Sediment CaCO3 401 Buffering by Weathering 402 Kinetic Constraints 402 Atmospheric Pulse Response 402 Ocean Uptake and Buffering with Dissolved Carbonate 403 Buffering by Sediment CaCO3 405 Anthropogenic CO2 Uptake 405 Direct Estimation 406 Reconstruction of Anthropogenic CO2 Inventory 408 The Atmospheric Oxygen Method 413 The Role of Biology 414 Future CO2 Uptake 415 10.3 Interannual to Decadal Timescale Variability 417 Tropical Variability 419 Extratropical Variability 423 10.4 Glacial-Interglacial Atmospheric CO2 Changes 429 Setting the Scene 431 Terrestrial Biosphere Carbon Loss 431 Salinity Changes 432 Temperature Changes 434 Fundamental Mechanisms 435 Southern Ocean Dominance 435 Equilibration of Low-Latitude Changes 436 Closing the Southern Ocean Window 440 Physical Mechanisms 442 Biological Mechanisms 443 Observational Constraints 444 A Role for the Regions outside the Southern Ocean? 446 Circulation Scenarios 447 Soft-Tissue Pump Scenarios 447 Alkalinity and Carbonate Pump Scenarios 449 A Synthesis Scenario 452 Problems 454 Appendix 459 References 461 Index 495

"This textbook is a monumental and masterful achievement, and the authors should be congratulated both for taking on this important task and for the end result... Every serious student and post-doc in this discipline, and all senior practitioners, should purchase or borrow a copy of this book and read it from cover to cover."--David M. Karl, Bulletin of the American Society for Limnology and Oceanography "Readers of Environmental Conservation with an interest in marine biogeochemistry and earth system science are encouraged to purchase or borrow this book. It is a comprehensive text on a complex and timely topic, and is one that will enlighten students and professionals alike. The authors are to be congratulated on their tour-de-force."--Peter Burkill, Environmental Conservation