This book presents a systemic view of the diversity of pressures and impacts produced by climate change and human actions. Erosion of biodiversity by changing ocean chemistry, the intensification of global change raises the problem of the adaptation of living resources.

Land uses induce ecological imbalances leading to asphyxiation true coastal ecosystems. More than a billion tons of solid waste must be assimilated by the marine environment and food webs. Radioactive discharges emitted into the atmosphere or into the aquatic environment, raise the question of their future.

Sea and Ocean series offers a transversal approach of the ocean system that leads to governance, sustainable resource management and adaptation of societies.

André Monaco is Emeritus Director of Research for the French national research center (CNRS). His research interests concern marine sedimentology and geochemistry. He was responsible for part of the organizing committee for several French and European programs and has been guest editor for four special issues in international journals.

Patrick Prouzet is Director of Research focusing on the ecosystemic approach at Ifremer in France. He specializes in the biology and dynamics of anadromous fish such as Atlantic salmon and eels. He is the author or co-author of several works on these species or on estuary fishing.

FOREWORD ix

CHAPTER 1. CONTINENTSEA INTERFACE: A HYDROGEOLOGICAL CONTINUUM 1Nathalie DÖRFLIGER, Bertrand AUNAY and Perrine FLEURY

1.1. Introduction 2

1.2. Landsea interface: from geology to the hydrogeological continuum 3

1.2.1. The continentocean continuum 4

1.2.2. The landsea continuum: islands 16

1.3. Problems with the management of water resources of coastal aquifers 18

1.3.1. Coastal aquifers of sedimentary basins 22

1.3.2. Karstic coastal aquifers 26

1.3.3. Coastal insular volcanic aquifers 30

1.4. Conclusion and perspectives 30

1.5. Bibliography 31

CHAPTER 2. CHEMICAL ELEMENTS AND ISOTOPES, TRACERS OF LANDSEA EXCHANGES 39Catherine JEANDEL, Pieter VAN BEEK and François LACAN

2.1. Introduction 39

2.1.1. Marine geochemistry and the concept of a tracer 40

2.2. Groundwater discharge into the sea and estimate of the age of coastal waters: Ra isotopes 42

2.2.1. Ra isotopes, how do they work? 42

2.2.2. Submarine groundwater discharge 44

2.2.3. Age of water bodies and horizontal transport 47

2.3. Boundary exchange: what do isotopes of neodymium and thorium bring? 48

2.3.1. Isotopes of neodymium, how does this work? 48

2.3.2. Input of Nd isotopes 50

2.3.3. Isotopes of Th: how does this work? 56

2.3.4. Thorium: indicator for wide coastal exchanges, e.g. the Mediterranean 57

2.3.5. Contribution of experimental methods: initial particle/ dissolute reaction kinetics 58

2.4. Which processes release Fe from ocean margins: the Fe isotope approach? 59

2.4.1. Besides being a tracer, what is the role of iron in the ocean? 59

2.4.2. Isotopes of iron 60

2.4.3. Clues about the processes that release iron 63

2.5. Conclusion 65

2.6. Bibliography 66

CHAPTER 3. EUTROPHICATION OF THE MARINE ENVIRONMENT 71Alain MÉNESGUEN

3.1. Manifestations of marine eutrophication 71

3.1.1. Macroalgal proliferations and anoxic malaigue 72

3.1.2. Phytoplanktonic proliferations and hypoxia 86

3.1.3. Toxic phytoplanktonic proliferations 94

3.1.4. Definition of marine eutrophication 109

3.2. Mechanisms of marine eutrophication 113

3.2.1. Hydrodynamic confinement 113

3.2.2. Nutrient enrichment 118

3.3. Regulatory monitoring of marine eutrophication and restoration efforts in eutrophicated zones 133

3.3.1. International assessment charts 133

3.3.2. Eutrophication indicators and their threshold values 142

3.3.3. Modeling: a tool for the understanding and remediation of eutrophication 150

3.4. Bibliography 163

CHAPTER 4. POLLUTION BY MARINE DEBRIS 193François GALGANI

4.1. Introduction 193

4.2. Cycle of ocean litter 195

4.2.1. Methods for evaluating debris at sea 195

4.2.2. Nature and quantity of debris flowing into the sea 198

4.2.3. Importance of plastic waste 200

4.2.4. Sources 202

4.2.5. Lifecycle and distribution 205

4.3. Degradation of litter at sea 210

4.4. Effects of marine litter on the environment 213

4.4.1. Ecological effects 213

4.5. Socioeconomic aspects 222

4.5.1. Legislative aspects (laws, conventions and directives) 222

4.5.2. Initiatives 226

4.5.3. Understanding and educating 230

4.6. Conclusion 232

4.7. Acknowledgments 234

4.8. Bibliography 234

4.8.1. Websites 236

CHAPTER 5. RADIOACTIVITY OF ANTHROPIC ORIGIN IN THE MARINE ENVIRONMENT 237Sabine CHARMASSON, Pascal BAILLY DU BOIS, Hervé THÉBAULT, Dominique BOUST and Bruno FIÉVET

5.1. Introduction 237

5.2. Sources of radionuclides in the marine environment 238

5.2.1. Atmospheric weapons testing 238

5.2.2. Major accidents 240

5.2.3. Liquid releases from nuclear facilities operating normally 243

5.2.4. Waste 244

5.3. Worldwide oceanic distribution 245

5.3.1. In surface waters 245

5.3.2. In the water column 247

5.4. Behavior and fate in ecosystems 249

5.4.1. Water compartment 251

5.4.2. Behavior of radionuclides related to sediments and material in suspension 258

5.4.3. Transfers of radionuclides to marine species 267

5.5. Vulnerability of coastal areas 274

5.5.1. Dispersal in the sea of contaminants hydrosedimentary modeling 275

5.5.2. Sensitivity of coastal areas 276

5.6. Conclusion 279

5.7. Bibliography 280

LIST OF AUTHORS 283

INDEX 285