Ray, RaghabMiyajima, ToshihiroWatanabe, AtsushiYoshikai, MasayaFerrera, Charissa M.Orizar, IrisNakamura, TakashiSan Diego‐McGlone, Maria LourdesHerrera, Eugene C.Nadaoka, Kazuo2025-06-152021-09-24Ray, R., Miyajima, T., Watanabe, A., Yoshikai, M., Ferrera, C. M., Orizar, I., Nakamura, T., Diego‐McGlone, M. L. S., Herrera, E. C., & Nadaoka, K. (2021). Dissolved and particulate carbon export from a tropical mangrove‐dominated riverine system. <i>Limnology and Oceanography</i>, <i>66</i>(11), 3944–3962.0024-35901939-559010.1002/lno.11934https://hdl.handle.net/20.500.14697/569We are grateful to the Japan International Cooperation Agency (JICA) and Japan Science and Technology Agency (JST) through the Science and Technology Research Partnership for Sustainable Development Program (SATREPS) for financially supporting the Project “Comprehensive Assessment and Conservation of Blue Carbon Ecosystems and their Services in the Coral Triangle (BlueCARES).” We are indebted to Dr Gerd Gleixner and Steffen Ruehlow (MPI-Jena, Germany) for providing support in δ¹³DOC analyses, and Dr Naoko Morimoto for POM analyses. We sincerely thank Dr Kenji Ono for sharing fine root production data. We are thankful to Dr Ariel Blanco (Department of Geodetic Engineering, UP Diliman) for providing delineation of mangrove area and Dr. Enrico C. Paringit, program leader of Phil-LiDAR 1, for providing the LiDAR products for map preparation. We thank Jeffrey Munar, Jesus Abad, John Michael Aguilar, Dominic Bautista, Bryan C. Hernandez and Mr Tsuyoshi Kanda for their assistance during field surveys. We are grateful for the overall support given by the University of the Philippines, Diliman and Aklan State University to the project. Finally, we thank the Journal Editor, Associate Editor, and three reviewers for their valuable comments and corrections on the manuscript.Despite being a major component in the mangrove carbon (blue carbon) budget, “outwelling” flux (or export to the sea) has gained little attention relative to other biogeochemical fluxes and reservoir carbon stock estimations. This study aims to estimate lateral exchange fluxes of dissolved and particulate organic carbon (DOC, POC) and dissolved inorganic carbon (DIC) from the watershed through a microtidal mangrove-dominated estuary to the coastal sea in Panay Island, Philippines. Along the estuarine transect, consistent addition of DOC, DIC, and POC at higher salinities were attributed to mangrove organic matter input. Upstream groundwater input (carbonate weathering) and downstream mangrove organic matter decomposition (possibly sulfate reduction) were the main controls on DIC. DOC corresponded to relatively pure mangrove sources in creek water, while POC was a mixture of detrital and algal organic matter. The mangrove system acted as net exporter of carbon to the sea in both dry and wet seasons. From short-term observations, outwelling fluxes of mangrove-derived DOC, DIC, and POC contributed 27–53%, 8–31%, and 42%, respectively, to their estuarine outflow. Unlike other studies, such low percentage for DIC might result from other external nonmangrove input (e.g., watershed carbonate weathering). Overall estuarine carbon flux was dominated by DIC (90–95%) with only minor contribution from DOC. The approach utilized in this study to estimate lateral carbon flux specific to a small mangrove setting can be useful in delineating blue carbon budgets that avoid geographical and methodological biases.enMangrove areasMangrove forestsSeawater--Organic compound contentHydrodynamicsArticleSDG 13 - Climate actionSDG 14 - Life below waterSDG 15 - Life on landmangrovesblue carbondissolved organic carbonparticulate organic carbondissolved inorganic carbonhydrodynamicsChallenge 2: Protect and restore ecosystems and biodiversityChallenge 5: Unlock ocean-based solutions to climate change