Ocean Biogeochemical Dynamics provides a broad theoretical framework upon which graduate students and upper-level undergraduates can formulate an understanding of the processes that control the mean concentration and distribution of biologically utilized elements and compounds in the ocean. Though it is written as a textbook, it will also be of interest to more advanced scientists as a wide-ranging synthesis of our present understanding of ocean biogeochemical processes.
The first two chapters of Ocean Biogeochemical Dynamics provide an introductory overview of biogeochemical and physical oceanography. The next four chapters concentrate on processes at the air-sea interface, the production of organic matter in the upper ocean, the remineralization of organic matter in the water column, and the processing of organic matter in the sediments. The focus of these chapters is on analyzing the cycles of organic carbon, oxygen, and nutrients.
The next three chapters round out the authors' coverage of ocean biogeochemical cycles with discussions of silica, dissolved inorganic carbon and alkalinity, and CaCO3. The final chapter discusses applications of ocean biogeochemistry to our understanding of the role of the ocean carbon cycle in interannual to decadal variability, paleoclimatology, and the anthropogenic carbon budget. The problem sets included at the end of each chapter encourage students to ask critical questions in this exciting new field. While much of the approach is mathematical, the math is at a level that should be accessible to students with a year or two of college level mathematics and/or physics.
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
Jorge L. Sarmiento is Professor of Geosciences at Princeton University. Nicolas Gruber is Associate Professor of Geophysics at the University of California, Los Angeles.
"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
"Ocean Biogeochemical Dynamics is an outstanding text for student and professional alike. The authors have developed an exceptionally lucid yet detailed discussion of the major biogeochemical cycles in the oceans, culminating in a quantitative examination of climate change and the contemporary carbon cycle. The book is a tour de force that should be incorporated into all marine chemistry and biogeochemistry courses."
– Paul Falkowski, Rutgers University
"Global ocean research projects during the past two decades have resulted in explosive growth in our knowledge of ocean biogeochemistry. Sarmiento and Gruber's book crystallizes this knowledge into a systematic quantitative treatise. For many years to come, this observation – and equation-filled volume will serve as a window into the literature on many subjects, a textbook for our classes, and a reference book on our desks. Studied carefully, it could teach chemical, biological, and physical oceanographers to speak a common language."
– Edward A. Boyle, Massachusetts Institute of Technology
"With this book, ocean biogeochemistry – the fascinating science behind the cycling of elements in the sea, and their transformation by biological, chemical, and physical properties – has finally found its theoretical underpinning. The two authors, both world experts, have succeeded in bringing together in a comprehensive and unified way the mass of information from the different scientific disciplines as well as the numerous observations obtained over the last few decades. This book will serve as the ultimate reference, both for students and the advanced research scientist, for many years to come."
– Martin Heimann, Max Planck Institute for Biogeochemistry
"The Sarmiento and Gruber text is a very impressive achievement, providing a readable yet advanced treatise on ocean biogeochemistry and providing the best available summary of the advances of the last few decades. The emphasis on dynamics is highly relevant for studies of global change, while the emphasis on problem solving has yielded an invaluable teaching reference."
– Ralph Keeling, Scripps Institution of Oceanography
"Sarmiento and Gruber have cleverly found the middle ground between the "educated layman" approach so often typified in "soft sciences" and the stultifying rigor that cloaks the conceptual simplicity underlying many of the foundations of the field. They don't shy away from mathematical explanations but rather use them to make their points succinctly, and to clarify what is often a confused muddle in more basic texts."
– W.J. Jenkins, Woods Hole Oceanographic Institution