Blue carbon stock heterogeneity in Brazilian mangrove forests: A systematic review

This is the first systematic review and meta-analysis of blue carbon stocks in Brazilian mangroves. We evaluated the effect of characteristics and site status (impacted versus non-impacted) on carbon stocks found in the various compartments or on total ecosystem carbon stock (TECS). TECS followed an inverse trend with the latitudinal position: the highest values were found on the North coast (mean 511 Mg C ha−1), followed by the Northeast and Southeast. A similar latitudinal trend was observed for sediment and above-ground biomass carbon stocks. Site status also significantly affected TECS and sediment carbon stocks. The heterogeneity observed in carbon stocks suggests that tidal regime, latitudinal position, climate, and site status jointly drive the processes related to sequestration and storage. Brazilian mangroves store ~0.44 PgC, representing 10–12 % of the world TECS. This highlights Brazilian mangroves as a global blue carbon hotspot, and as an efficient nature-based solution for carbon dioxide removal. •Carbon stocks for all Brazilian mangroves amount to ~ 0.44 PgC representing 10 - 12% of mangrove carbon stocks worldwide;•No estimates of carbon stocks were found in two Amazonian states (Amapa and Maranhao), that represent ~55% of Brazilian mangroves;•No estimates of carbon stocks were found for the South Brazilian states (Parana and Santa Catarina), that correspond to the southern limit of mangrove ecosystems distribution in the Americas;•Carbon stocks vary greatly across regions, calling for more research in non-investigated areas;•The site status of mangrove ecosystems strongly influences carbon stocks, calling for conservation and (re)-establishment actions to safeguard globally relevant blue carbon stocks.