Tomohiro Kuwae · Masakazu Hori Editors Blue Carbon in Shallow Coastal Ecosystems Carbon Dynamics, Policy, and Implementation Blue Carbon in Shallow Coastal Ecosystems Tomohiro Kuwae • Masakazu Hori Editors Blue Carbon in Shallow Coastal Ecosystems Carbon Dynamics, Policy, and Implementation Editors Tomohiro Kuwae Masakazu Hori Coastal and Estuarine Environment National Research Institute of Fisheries Research Group and Environment of Inland Sea Port and Airport Research Institute Japan Fisheries Research and Education Yokosuka, Japan Agency Hatsukaichi, Hiroshima, Japan ISBN 978-981-13-1294-6 ISBN 978-981-13-1295-3 (eBook) https://doi.org/10.1007/978-981-13-1295-3 Library of Congress Control Number: 2018953287 © Springer Nature Singapore Pte Ltd. 2019 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore Foreword Tomohiro Kuwae and Masakazu Hori’s Blue Carbon in Shallow Coastal Ecosystems: Carbon Dynamics, Policy, and Implementation is a major contribution to blue car- bon science, providing a solid reference source to those starting to consider this important aspect of environmental sciences. Most importantly, this book provides a unique effort to broaden the scope of blue carbon by also addressing nonconven- tional blue carbon ecosystems, such as macroalgal stands and corals, with a rich suite of examples from a range of coastal ecosystems in Japan. As a unique contri- bution, the contributing authors integrate the fluxes of CO that these coastal habi- 2 tats support at the global scale for the first time, a prerequisite to evaluate the efficiency of various policy actions to strengthen the role of blue carbon ecosystems in climate change mitigation. I strongly recommend this book to students and schol- ars interested in climate change and the role that conservation and restoration of coastal ecosystems may play in mitigating climate change. Professor of Marine Science, Red Sea Research Center Carlos M. Duarte King Abdullah University of Science and Technology, Thuwal, Saudi Arabia v Preface The term “blue carbon” was coined by the United Nations Environment Programme in 2009 and is still rather new. However, this concept and the role of blue carbon stored in shallow coastal ecosystems (SCEs) as a climate mitigation measure have attracted the interest of many people worldwide. Some such typical ecosystems (e.g., mangroves, tidal marshes, and seagrass meadows) are now being called “blue carbon ecosystems.” The number of publications dealing with blue carbon has been increasing exponentially since the genesis of the term, and the science of blue car- bon and its role within the context of the mitigation of global warming seem to be rapidly maturing. However, there are very few comprehensive books about blue carbon and the role of carbon storage and CO uptake in SCEs. 2 The suppression of CO emissions to the atmosphere by blue carbon storage is a 2 process that reduces atmospheric CO concentrations and mitigates climate change 2 indirectly. The net uptake of atmospheric CO through the exchange of CO at the 2 2 air–ecosystem interface accomplishes the same goal directly. The role of both blue carbon storage and CO gas uptake should therefore be considered when SCEs are 2 targeted for climate change mitigation. However, we feel that there is a disciplinary division between these two blue carbon-related sciences: ecologists seem to focus on biological processes, biogeochemists consider carbon cycling, and meteorolo- gists study greenhouse gas fluxes and physicochemical processes. In addition to the classical blue carbon SCEs, other SCEs, including macroalgal beds, tidal flats, coral reefs, and embayments, are drawing attention as sites that could potentially contribute to climate change mitigation. However, there is very little published scientific information on these new potential climate change mitiga- tion areas. From the standpoint of policy and implementation, about 20% of the countries that approved the Paris Agreement have pledged in their Nationally Determined Contributions (NDCs) to use SCEs as a climate change mitigation option and are moving toward measuring blue carbon inventories. About 40% of those same coun- tries have pledged to use SCEs to adapt to climate change. Australia has begun including blue carbon as a national carbon offset scheme, and as discussed in this book, Yokohama City, Japan, has also started using SCEs for carbon credit trading. vii viii Preface Blue Carbon in Shallow Coastal Ecosystems: Carbon Dynamics, Policy, and Implementation Chapter 1. Introduction Carbon Stock and Flow at Ecosystem Scales Carbon Storage Gas Exchange Chapter 2. Background, Chapter 6. Background, Theory, Sediments Theory, Methods, Shallow Coastal Ecosystems Chapter 3. Mangroves Chapter 7. Mangroves Chapter 4. Seagrasses and Macroalgae Chapter 8. Tidal Flat and Marsh Ecosystems Chapter 5. Tidal Flat Ecosystems Carbon Stock and Flow at Estuarine and Coastal Scales Chapter 9. Seagrass Carbon Transport Chapter 10. Carbon Dynamics in Coral Reefs Chapter 11. Carbon Dynamics in Human-dominated Waters Policy and Implementation Chapter 12. Carbon Offset Project Utilizing Coastal Waters Chapter 13. Future of Blue Carbon Fig. 1 Overview of this book An overview and the highlights of this book are shown in Fig. 1 and Table 1, respectively. In consideration of the background described above, we chose the sub- ject, purpose, and features of this book as follows: 1. Compilation of very recent studies and quantitative assessment of relevant pro- cesses and mechanism to demonstrate how much SCEs can take up CO and 2 store carbon and how they can contribute to climate change mitigation Preface ix Table 1 Chapter highlights Chapter 1 Introduction of blue carbon and carbon cycling (carbon storage and CO gas flux) 2 in shallow coastal ecosystems Chapter 2 Distribution pattern and chemical and genetic characteristics of sedimentary organic carbon on a timescale of several thousand years and factors controlling rates of burial in marine and seagrass sediments Chapter 3 Global distribution of mangrove biomass, carbon stocks, and carbon burial rates in mangroves Chapter 4 Japan nationwide estimate of carbon sequestration potential (annual plant tissue production) in seagrass and macroalgal beds Chapter 5 Carbon stocks and flows in tidal flat ecosystems, especially for rates of microalgal production and bivalve-related organic and inorganic carbon, with special emphasis on Japanese sites Chapter 6 Theory, methods (bulk formula, chamber, eddy-covariance), and empirical studies of air-water CO fluxes in shallow coastal waters, which are sinks for atmospheric 2 CO. 2 Chapter 7 Three types of CO fluxes (atmosphere-ecosystem, air-soil, air-water) in 2 mangrove ecosystems, with special emphasis on the Sundarban, the world’s largest mangrove forest Chapter 8 Three types of CO fluxes (atmosphere-ecosystem, air-sediment, air-water) in 2 tidal flat and marsh ecosystems, with special emphasis on Japanese sites Chapter 9 Numerical model to estimate transport of the sequestered carbon from eelgrass beds through shallow coastal waters to the deep sea, and the process of carbon storage both within eelgrass beds and off sites Chapter 10 Carbon cycle (CO sink/source, carbon storage, and export) in coral reefs and 2 interrelationships between coral reefs and other ecosystems such as seagrass meadows and mangroves Chapter 11 Blue carbon ecosystems, estuaries, and embayments as sinks for atmospheric CO under some biogeochemical and socio-economic conditions, e.g., 2 appropriate management of wastewater treatment Chapter 12 A social experiment conducted by Yokohama City, Japan, that served to counter climate change and included a novel carbon offset campaign utilizing coastal waters Chapter 13 Summary of carbon flows and stocks in various shallow coastal ecosystems reported in previous chapters, current status of blue carbon discussions at the international level, and future needs for policy making and social implementation 2. Inclusion of not only classical blue carbon ecosystems (i.e., mangroves, seagrass meadows, and salt marshes) but also macroalgal beds, tidal flats, coral reefs, and shallow waters near urban areas to show the potential of these ecosystems to serve as new carbon sinks 3. A thorough review of the literature, including many Japanese case studies, on blue carbon studies of not only topics that are currently research foci (i.e., sedi- mentary carbon stocks and accumulation rates [indirect processes for reducing atmospheric CO]) but also exchanges of CO gas between the atmosphere and 2 2 SCEs (direct processes for reducing atmospheric CO), carbon storage in the 2 water column as refractory organic carbon, and off-site carbon storage (e.g., the deep sea) x Preface 4. Compilation of international policies and frameworks related to blue carbon and a case study of the application and implementation thereof (carbon offset credit) in Japan We hope that this book will provide readers with a comprehensive and up-to-date understanding of the state-of-the-art science, technology, and policies related to blue carbon. We believe that publication of this book is timely because the Paris Agreement calls for initiation of climate change measures in 2020 and many coun- tries have pledged in their NDCs to utilize SCEs as described above. We anticipate that the audience of this book will be broad and will include pro- fessionals (e.g., managers and policymakers in local and national governments, con- servationists, engineers involved with dredging companies, costal environmental consultancies, NPOs, and NGOs), academics (coastal ecologists, biogeochemists, fisheries scientists, civil engineers, and climate scientists), and all levels of students and educators from undergraduates to university faculty. Acknowledgments We thank Drs. Miyajima and Tokoro for their help in reviewing several chapters. We also thank the editors of Springer Nature (Ms. Mei Hann Lee and Ms. Sivachandran Ravanan) for their help and encouragement and ELSS, Inc., for English language editing. This book was supported in part by the Environment Research and Technology Development Fund (Strategic R&D Area Project [S-14 and S-15] and 2-1712) of the Ministry of the Environment, Japan; Canon Foundation grant; Grants-in-Aid (KAKENHI, nos. 24656316, 26630251, 15K18145, 24760430, 15K18146, 18H04156) from the Japan Society for the Promotion of Science; JST- JICA SATREPS project BlueCARES; National Remote Sensing Centre (NRSC), Department of Space, India; grant for the Survey and Facilities of Ports from the Ministry of Land, Infrastructure, Transport and Tourism, Japan; and a Grant-in-Aid for the Promotion of Global Warming Countermeasures from the Fisheries Agency of the Ministry of Agriculture, Forestry and Fisheries, Japan. Yokosuka, Japan Tomohiro Kuwae Hiroshima, Japan Masakazu Hori Contents 1 Blue Carbon: Characteristics of the Ocean’s Sequestration and Storage Ability of Carbon Dioxide . . . . . . . . . . . . . . . . . . . . . . . . . 1 Masakazu Hori, Christopher J. Bayne, and Tomohiro Kuwae 2 Carbon Sequestration in Sediment as an Ecosystem Function of Seagrass Meadows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Toshihiro Miyajima and Masami Hamaguchi 3 Carbon Sequestration in Mangroves . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Tomomi Inoue 4 Carbon Sequestration by Seagrass and Macroalgae in Japan: Estimates and Future Needs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Goro Yoshida, Masakazu Hori, Hiromori Shimabukuro, Hideki Hamaoka, Toshihiro Onitsuka, Natsuki Hasegawa, Daisuke Muraoka, Kousuke Yatsuya, Kentaro Watanabe, and Masahiro Nakaoka 5 Carbon Storage in Tidal Flats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Toru Endo and Sosuke Otani 6 Air–Water CO Flux in Shallow Coastal Waters: Theory, 2 Methods, and Empirical Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Tatsuki Tokoro, Kenta Watanabe, Kazufumi Tada, and Tomohiro Kuwae 7 CO Fluxes in Mangrove Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . 185 2 Anirban Akhand, Abhra Chanda, Sourav Das, Sugata Hazra, and Tomohiro Kuwae 8 CO Flux in Tidal Flats and Salt Marshes . . . . . . . . . . . . . . . . . . . . . . 223 2 Sosuke Otani and Toru Endo xi