Ocean Biogeochemistry

Oceans account for 50% of the anthropogenic CO 2 released into the atmosphere. During the past 15 years an international programme, the Joint Global Ocean Flux Study (JGOFS), has been studying the ocean carbon cycle to quantify and model the biological and physical processes whereby CO 2 is pumped from the ocean's surface to the depths of the ocean, where it can remain for hundreds of years. This project is one of the largest multi-disciplinary studies of the oceans ever carried out and this book synthesises the results. It covers all aspects of the topic ranging from air-sea exchange with CO 2 , the role of physical mixing, the uptake of CO 2 by marine algae, the fluxes of carbon and nitrogen through the marine food chain to the subsequent export of carbon to the depths of the ocean. Special emphasis is laid on predicting future climatic change.

Overall representation of the role of the ocean in the global carbon cycle Includes supplementary material: sn.pub/extras

Texte du rabat

Oceans account for 50% of the anthropogenic CO2 released into the atmosphere. During the past 15 years an international programme, the Joint Global Ocean Flux Study (JGOFS), has been studying the ocean carbon cycle to quantify and model the biological and physical processes whereby CO2 is pumped from the ocean's surface to the depths of the ocean, where it can remain for hundreds of years. This project is one of the largest multi-disciplinary studies of the oceans ever carried out and this book synthesises the results. It covers all aspects of the topic ranging from air-sea exchange with CO2, the role of physical mixing, the uptake of CO2 by marine algae, the fluxes of carbon and nitrogen through the marine food chain to the subsequent export of carbon to the depths of the ocean. Special emphasis is laid on predicting future climatic change.

Contenu
Acknowledgements.- References.- 1 Biogeochemical Provinces: Towards a JGOFS Synthesis.- 1.1 Plankton Community Structure and Distribution.- 1.2 Partitioning the Oceans.- 1.3 Primary Production in Ocean Domains and Provinces.- 1.4 Bacterial Production and DOC Flux.- 1.5 A Provincial Outlook.- Acknowledgements.- References.- 2 Physical Transport of Nutrients and the Maintenance of Biological Production.- 2.1 Introduction.- 2.2 Global Overturning Circulation and Nutrient Transport.- 2.3 Convection.- 2.4 Wind-Driven Circulations: Gyres and Boundary Currents.- 2.5 Smaller-Scale Circulations: Mesoscale Eddies, Waves and Sub-Mesoscale Fronts.- 2.6 Interannual and Long-Term Variability.- 2.7 Conclusions.- Acknowledgements.- Notes.- References.- 3 Continental Margin Exchanges.- 3.1 Introduction.- 3.2 Recycling Systems.- 3.3 Export Systems.- 3.4 Coastal Upwelling Systems.- 3.5 California Current System.- 3.6 Humboldt Current System.- 3.7 Benguela Current System.- 3.8 Monsoonal Upwelling Systems.- 3.9 Biogeochemical Budgeting.- 3.10 The Arctic Shelves.- 3.11 Marginal Seas.- Acknowledgments.- References.- Apendix 3.1 Continental Margins: Site Descriptions.- 4 Phytoplankton and Their Role in Primary, New, and Export Production.- 4.1 Introduction.- 4.2 Synthesis.- References.- 5 Carbon Dioxide Fluxes in the Global Ocean.- 5.1 Introduction.- 5.2 The Oceans' Influence on Atmospheric CO2.- 5.3 How Big is the Global Ocean Sink?.- 5.4 What Processes Control Air-Sea CO2 Flux?.- 5.5 Variability in the CO2 Signal.- 5.6 The Gas Transfer Velocity.- 5.7 Conclusion: the Next Ten Years.- Acknowledgements.- References.- 6 Water Column Biogeochemistry below the Euphotic Zone.- 6.1 Introduction.- 6.2 The Twilight Zone: Biology, Biogeochemical Processes and Fluxes.- 6.3 The Fluxes of BiogenicMatter versus Depth.- 6.4 The Variable Composition of the World Ocean Waters along the Conveyor Belt.- 6.5 Conclusions and Perspectives.- References.- 7 The Impact of Climate Change and Feedback Processes on the Ocean Carbon Cycle.- 7.1 Introduction.- 7.2 Feedbacks.- 7.3 What do Current Models Predict?.- 7.4 Status of Our Understanding of Feedbacks.- 7.5 Nutrient Dynamics.- 7.6 Phytoplankton and Carbon Limitation.- 7.7 The Calcifiers.- 7.8 Iron Supply to the Oceans.- 7.9 Dimethyl Sulphide and the Biota.- 7.10 UV-B and Ozone Depletion.- 7.11 Summary of Biotic Feedbacks.- 7.12 Climate Variability versus Change.- 7.13 Modeling Future Goals.- 7.14 The Future.- 7.15 Summary.- Acknowledgements.- References.- 8 Benthic Processes and the Burial of Carbon.- 8.1 Introduction.- 8.2 Processes of Transport and Turnover of Material in the Deep Ocean.- 8.3 Quantitative Estimates of Carbon Deposition and Carbon Turnover.- 8.4 Proxy Indicators of Paleoproductivity.- 8.5 Conclusions.- References.- 9 Global Ocean Carbon Cycle Modeling.- 9.1 Introduction.- 9.2 Anthropogenic Carbon Uptake, Transient Tracers, and Physics.- 9.3 Global Biogeochemical Cycles.- 9.4 Ecosystem Dynamics.- 9.5 Other Topics.- 9.6 Summary.- Acknowledgements.- References.- 10 Temporal Studies of Biogeochemical Processes Determined from Ocean Time-Series Observations During the JGOFS Era.- 10.1 Introduction.- 10.2 The Oceanic Carbon Cycle and the Biological Carbon Pump.- 10.3 Global Inventory of JGOFS Time-Series Programs.- 10.4 Some Practical Lessons Learned from the JGOFS Time-Series Programs.- 10.5 Cross Ecosystem Habitat Comparisons: Nutrient, Chlorophyll and Production-Export Relationships.- 10.6 Beyond JGOFS: a Prospectus.- Acknowledgements.- References.- 11 JGOFS: a Retrospective View.- 11.1 The JGOFSScience Plan.- 11.2 The Process Studies.- 11.3 Iron Fertilisation Experiments.- 11.4 The Time Series Stations.- 11.5 The Global Survey.- 11.6 Remote Sensing.- 11.7 Benthic Studies.- 11.8 Continental Margins.- 11.9 Data Archiving.- 11.10 Models and Synthesis.- 11.11 Overall Conclusions.- References.