Marine geochemistry : ocean circulation, carbon cycle and climate change / Matthieu Roy-Barman and Catherine Jeandel.

Format:

Book

Author/Creator:

Roy-Barman, Matthieu, author.

Jeandel, Catherine, author.

Language:

English

Subjects (All):

Chemical oceanography.

Marine sediments.

Geochemistry.

Biogeochemistry.

Physical Description:

xxiii, 398 pages : illustrations (some color) ; 25 cm

Edition:

First edition.

Place of Publication:

Oxford : Oxford University Press, 2016.

Summary:

Marine geochemistry uses chemical elements and their isotopes to study how the ocean works in terms of ocean circulation, chemical composition, biological activity and atmospheric CO

Contents:

1 A Few Bases of Descriptive and Physical Oceanography 1

1.1 The Size of the Ocean 1

1.2 Salinity, Temperature and Density: The Basic Parameters of the Oceanographer 2

1.2.1 Salinity 3

1.2.2 Temperature 4

1.2.3 Density 5

1.3 Vertical Structure of the Ocean 6

1.4 The Main Water Masses 9

1.5 Ocean Currents 13

1.5.1 Surface Circulation 13

1.5.2 The Physical Principles 15

1.5.3 The Wind-Driven Ocean Circulation 18

1.5.4 Ekman Pumping 21

1.5.5 Coastal Up welling 25

1.5.6 Geostrophic Currents 26

1.6 Large-Scale Circulation 31

1.6.1 Vorticity 31

1.6.2 Sverdrup Balance 33

1.6.3 The Intensification of the Western Boundary Currents 37

1.6.4 Eddies and Recirculation 38

1.6.5 The Thermocline Ventilation 38

1.6.6 The Equatorial Circulation 40

1.6.7 The Deep Circulation 41

Appendix 1 The Atmospheric Forcing 43

Problems 44

2 Seawater Is More than Salted Water 49

2.1 Why Is Seawater Salty? 50

2.1.1 The Chemical Composition of Salt 50

2.1.2 Residence Time 51

2.1.3 Rivers and Estuaries 51

2.1.4 The Atmosphere 52

2.1.5 Volcanic and Hydrothermal Processes 52

2.1.6 The Removal of Chemical Elements 53

2.2 Concept of Conservative and Non-Conservative Tracers 54

2.3 The Nutrient Cycle and the Role of Biological Activity 55

2.3.1 Nutrient Profiles in Seawater 55

2.3.2 The Life Cycles in the Ocean 55

2.3.3 Influence of Deep Circulation on the Nutrient Distribution 60

2.4 Gases in Seawater 62

2.4.1 Definition of Apparent Oxygen Utilization 65

2.5 Relationships between the Different Tracers 65

2.5.1 Extracting the Conservative Fraction of a Tracer 65

2.5.2 Construction of Conservative Tracers 66

2.5.3 Horizontal and Vertical Changes of Tracers 68

2.6 Carbon Chemistry 70

2.6.1 The Carbonate System 70

2.6.2 Calcium Carbonate 73

2.6.3 Organic Carbon 74

2.7 The Redox Conditions in the Ocean 75

2.8 Behavior of Trace Metals 78

2.8.1 The Different Types of Profiles 78

2.8.2 Oxidation and Reduction of Manganese 79

2.8.3 Complexation of Iron 81

2.9 Many Open Questions 83

Appendix 1 83

Problems 87

3 Stable Isotopes 91

3.1 What Is an Isotope? 91

3.2 Notations 93

3.3 The Different Types of Fractionations: The Oxygen Example 95

3.3.1 Kinetic Fractionations 95

3.3.2 Thermodynamic Fractionations 95

3.3.3 Seaside Analogy 97

3.3.4 The "Biological" Fractionations 97

3.3.5 Mass-Dependent and Mass-Independent Fractionations 97

3.3.6 Clumped Isotopes 98

3.4 Oxygen Isotope Fractionation 100

3.4.1 The Fractionations in the Water Cycle 100

3.4.2 Isotope Exchange between Water and Solid 103

3.5 Hydrogen Isotope Fractionation 103

3.6 Carbon Isotope Fractionation 103

3.6.1 Fractionations in the Carbonate System 104

3.6.2 Biological Fractionations 106

3.6.3 The δ¹³C-PO³⁻₄ Relationship in Seawater 107

3.7 Nitrogen Isotope Fractionation 108

3.8 Sulfur Isotope Fractionation 110

3.9 Boron Isotope Fractionation 111

3.10 Silicon Isotope Fractionation 112

3.11 Iron Isotope Fractionation 112

3.12 Mixing of Isotopic Tracers 115

3.12.1 Conservative Mixing 116

3.12.2 Non-Conservative Mixing 119

3.13 Evolution of the Isotopic Signature during a Reaction 120

3.13.1 Example: Nitrate Assimilation by Phytoplankton 121

Appendix 1 Evolution of Isotopic Signatures during Fractionation Processes 122

Problems 125

4 Radioactive and Radiogenic Isotopes 129

4.1 Radioactivity 129

4.2 The Radioactive Decay Law and its Applications 130

4.2.1 The Radioactive Decay Law 130

4.2.2 Disintegration without Simultaneous Production 131

4.2.3 Disintegration with Simultaneous Production 133

4.2.4 Definition of the Activity 134

4.3 The Long-Lived Radioactive Decay Systems 136

4.3.1 Strontium 137

4.3.2 Neodymium 139

4.3.3 Lead 141

4.3.4 Helium 142

4.4 The Uranium and Thorium Decay Chains 143

4.5 Cosmogenic Isotopes 147

4.5.1 The ¹⁴C Isotope 147

4.5.2 The ¹⁰Be Isotope 150

4.6 Artificial Isotopes 151

Appendix 1 155

Integration of the Radioactivity Equation for a Closed System without Production Term 155

Integration of the Radioactivity Equation for a Closed System with Production Term 156

Calculation of the Mean Lifetime of an Isotope 158

Problems 159

5 Box Models 162

5.1 One-Box Model 162

5.1.1 The Conservation Equation 162

5.1.2 Case of Enzyme Kinetics 164

5.1.3 Steady State 165

5.1.4 Residence Time 165

5.2 Dynamic Behavior of a Reservoir 166

5.2.1 Constant Forcing 166

5.2.2 Temporal Evolution of the Forcings 168

5.3 Box Models and Isotopic Tracers 170

5.3.1 Use of U and Th Decay Chains 170

5.3.2 Using the Isotopic Composition of a Tracer 171

5.3.3 Application Exercise: Ventilation of the Deep Waters in the Red Sea 172

5.4 Dynamics of Coupled Boxes 175

5.5 Mean Age, Residence Time and Reservoir Age of a Tracer 177

Problems 179

6 Advection-Diffusion Models 183

6.1 An Infinitesimal Box 183

6.2 Advection 184

6.3 Molecular Diffusion 186

6.3.1 Random Walk 186

6.3.2 The Fick Law 187

6.3.3 Gas Diffusion at the Air-Sea Interface 189

6.4 Eddy Diffusion 191

6.5 The Full Conservation Equation 193

6.5.1 Example 1: Radium Transport in Coastal Waters 195

6.5.2 Example 2: Dispersion of SF<sub>6M/sub> in the Thermocline 199

6.6 The Case of Sediment Transport 201

Problems 203

7 Development and Limitations of Biological Activity in Surface Waters 206

7.1 Life Cycle in the Ocean 206

7.2 Development of the Biological Production in Surface Waters 213

7.3 Estimating the Primary Production 217

7.4 Global Distribution of Photosynthesis and Ocean Color 221

7.5 Iron Limitation 223

7.6 Silica Limitation 225

7.7 A CO₂ Limitation? 227

7.8 The Long-Term Limitation of the Production 228

7.9 Anthropogenic Impacts 229

Problems 231

8 CO₂ Exchanges between the Ocean and the Atmosphere 235

8.1 The Global Carbon Cycle 235

8.2 The Partial Pressure of CO₂ in Seawater 235

8.2.1 Temperature Effect 236

8.2.2 Carbonate System Effect 236

8.2.3 Photosynthesis 239

8.2.4 Remineralization 239

8.2.5 The Formation of Calcium Carbonate (CaCO₃) 239

8.2.6 CaC03 Dissolution 240

8.2.7 Overall Effect on the Pumping of CO₂ 241

8.3 The Carbon Storage Capacity of the Ocean 243

8.4 Rate of CO₂ Transfer at the Air-Sea Interface 245

8.5 Gas Equilibration Time between the Mixed Layer and the Atmosphere 248

8.5.1 Perturbation of Oxygen 248

8.5.2 Perturbation of the Carbonate System 248

8.5.3 Perturbation of the Isotopic Composition 249

8.6 Observation of the Anthropogenic Perturbation at the Ocean Surface 251

8.7 Global Estimate of the Ocean-Atmosphere Exchanges 251

8.8 Spread of the Anthropogenic Perturbation in the Deep Ocean 253

Problems 260

9 The Little World of Marine Particles 265

9.1 Origin and Nature of Marine Particles 265

9.2 Marine Particle Sampling 269

9.3 The Distribution of Particles 272

9.4 Particle Sinking 274

9.5 Changes of the Particle Flux with Depth 278

9.5.1 The Organic Matter Flux 278

9.5.2 The Mineral Phases 280

9.6 Estimation of the Particle Flux 280

9.6.1 234Th and Irreversible "Scavenging" Models 281

9.6.2 Relations between Small and Large Particles 284

9.6.3 230Th and Reversible Models 285

9.7 The Role of Margins 287

9.7.1 Boundary Scavenging 287

9.7.2 Boundary Exchange 289

9.8 The Distribution of Sediments on the Seafioor 291

9.9 The Diagenesis 292

9.10 Timescales and Sediment Fluxes 296

Problems 299

10 Thermohaline Circulation 302

10.1 The Long Path of Deep Waters 302

10.2 The Rapid Progression of Transient Tracers 308

10.2.1 Deep Current Dynamics 309

10.2.2 Intensity of the Recirculation 313

10.3 14C-Transient

Tracer Comparison 314

10.4 The Contribution of 231Pa-230Th 317

10.5 The Origin of the AABW 320

10.6 Closure of the Meridional Overturning Circulation 323

Problems 325

11 Ocean History and Climate Evolution 331

11.1 The Origin of the Ocean 331

11.2 The First Traces of Life 333

11.3 The Rise of Oxygen 333

11.4 Geological Sequestration of CO₂ 336

11.5 The Closure of the Panama Isthmus 339

11.6 The Last Glaciation 340

11.7 El Nino Exacerbated by Human Activity? 348

11.8 The Climate of the Future and the Ocean 350

11.9 The Expected Consequences 352.

Notes:

Includes bibliographical references and index.

ISBN:

9780198787495

0198787499

9780198787501

0198787502

OCLC:

946159805

Publisher Number:

99969467924