Author Identifier (ORCID)
Cristian Salinas’s ORCID record 
Madison Williams-Hoffman’s ORCID record
Abstract
Mangroves are widely recognized for their contribution to climate change mitigation. This study provides the first comprehensive assessment of top 1-m and 30-cm soil organic carbon (OC) stocks and accumulation rates across Western Australia’s mangroves, spanning multiple bioregions, geomorphological settings, and intertidal positions. The results revealed (mean ± SE) 236 ± 13 Mg and 83 ± 4 Mg OC ha−1 in top 1-m and 30-cm soils, respectively, accumulated at 443 ± 83 and 215 ± 22 kg OC ha−1 yr−1 over the past 100 and 500 years, respectively. Mangroves across Western Australia exhibited up to 3-fold differences in top 1-m stocks, with highest OC stocks in tropical settings (328 ± 54 Mg OC ha−1) and lowest in temperate mangroves (138 ± 15 Mg OC ha−1). At a landscape scale, mangroves within protected embayments and lower and mid intertidal positions held up to ∼1.5-fold higher OC stocks than those in estuarine settings and upper intertidal positions. Long-term accumulation rates varied up to 6-fold, with highest rates in semiarid bioregions and protected settings. Across 212,000 to 277,000 ha of mangrove extent in Western Australia, total stocks in 1-m soils were estimated at 71–86 Tg OC, accumulated at 94–123 Gg OC per annum. Western Australia’s ongoing mangrove losses have been estimated at 0.27% yr−1, which could result in 177–232 Gg CO2-eq yr−1 emissions. This study estimates the contribution of Western Australia’s mangroves to the global carbon cycle and provides the basis for improving current national carbon inventories and crediting frameworks.
Keywords
biogeochemistry, blue carbon, carbon crediting frameworks, carbon inventories, climate change, coastal vegetated ecosystems
Document Type
Journal Article
Date of Publication
9-1-2026
Article Number
118027
E-ISSN
18726259
ISSN
00167061
Volume
473
Publication Title
Geoderma
Publisher
Elsevier
School
Centre for Marine Ecosystems Research / School of Science
Funding Information
EG was supported by “Pla de Doctorats Industrials del Departament de Recerca i Universitats de la Generalitat de Catalunya”. MWH was supported by the Australian Radiation Protection and Nuclear Safety Agency and an Australian Government RTP stipend.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License
Recommended Citation
Gomis, E., Salinas, C., Williams-Hoffman, M., Said, N. E., Alarcón, M. S., Gorham, C., Werner, A., Lavery, P. S., Inostroza, K., Davies, T., Grierson, P. F., Hickey, S., Radford, B., Ballesteros, E., Kelleway, J. J., Masqué, P., Serrano, E., Macreadie, P. I., Lovelock, C. E., . . . Serrano, O. (2026). Soil organic carbon stocks and sequestration rates in Western Australia’s mangroves. Geoderma, 473, 118027. https://doi.org/10.1016/j.geoderma.2026.118027