Ray, RaghabSuwa, RempeiMiyajima, ToshihiroMunar, JeffreyYoshikai, MasayaSan Diego-McGlone, Maria LourdesNadaoka, Kazuo2025-03-232023-03-03Ray, R., Suwa, R., Miyajima, T., Munar, J., Yoshikai, M., San Diego-McGlone, M. L., & Nadaoka, K. (2023). Sedimentary blue carbon dynamics based on chrono-sequential observation in a tropical restored mangrove forest. <i>Biogeosciences Discussions</i>, <i>20</i>(4), 911–928.1726-418910.5194/bg-20-911-2023https://repository.unesco.gov.ph/handle/123456789/183We are grateful to the Japan International Cooperation Agency (JICA) and the Japan Science and Technology Agency (JST) through the Science and Technology Research Partnership for Sustainable Development (SATREPS) program for financially supporting the project Comprehensive Assessment and Conservation of Blue Carbon Ecosystems and their Services in the Coral Triangle (Blue CARES). We thank Jesus Abad, John Michael Aguilar, Dominic Bautista, Bryan C. Hernandez, and Tsuyoshi Kanda for their assistance during field surveys. We are grateful for the overall support given to the project by the University of the Philippines, Diliman, and Aklan State University. We are thankful to our Blue CARES colleague Charissa Ferrera for the support in language edits. Finally, authors sincerely thank AE (Jack Middelburg) and the reviewers for their constructive comments that have greatly improved the revised version of the manuscript.Among the many ecosystem services provided by mangroves, the sequestration of large amounts of organic carbon (OC) in marine ecosystems (also known as “blue carbon”) has given these unique ecological environments enormous global attention. While there are many studies on the blue carbon potential of intact mangroves (i.e., naturally growing), there have been very few studies on restored mangroves (i.e., planted). This study aims to address this knowledge gap by examining the sediment development process during the early colonization (rehabilitation) of mangroves in an OC-poor estuary in Panay Island, Philippines. Based on source apportionment of multiple end-members in the sedimentary organic matter, the contribution of mangrove plant material was higher at the older sites compared to the younger sites or bare sediments where there is a higher contribution of riverine input. A clear increasing gradient according to mangrove development was observed for bulk OC (0.06–3.4 µ mol g⁻¹, porewater OC (292–2150 µmol L⁻¹, sedimentary OC stocks (3.13–77.4 Mg C ha⁻¹), and OC loading per surface area (7–223 µmol m⁻²). The estimated carbon accumulation rates (6–33 mol m⁻² yr⁻¹) based on chronosequence are within the global ranges and show an increasing pattern with the age of mangroves. Hence, the sediments of relatively young mangrove forests appear to be a significant potential C sink, and short-term chronosequence-based observations can efficiently define the importance of mangrove restoration programs as a potential carbon sequestration pathway.enAttribution 4.0 Internationalhttps://creativecommons.org/licenses/by/4.0/Ecosystem servicesMangrove forestsMangrove ecologyCarbon sequestrationEcosystem servicesRestoration ecologyEstuarine ecologyClimate change mitigationSoils--Carbon contentArticleSDG 14 - Life below waterSDG 13 - Climate actionmangrovesmangrove restorationmangrove conservationcarbon sequestrationblue carbonsoil organic carbonenvironmental restorationecosystem servicesChallenge 5: Unlock ocean-based solutions to climate changeChallenge 2: Protect and restore ecosystems and biodiversity