Mangrove soil and vegetation carbon stocks in northeastern Brazil

Abstract Coastal ecosystems, including mangroves, are known as carbon sinks due to their high storage capacity per square meter. Despite playing this vital role, there remains a need for more information on carbon studies in mangrove areas in Brazil. Given this scenario, the primary objective of this study was to quantify the soil and vegetation carbon stocks in mangrove areas of Pernambuco, NE Brazil. The study was conducted in the Ecological Preservation Zone (ZPEC) of the Suape Port Industrial Complex (SPIC). Plots (20 × 50 m) were established for field measurements of tree height, circumference at breast height, and necromass, as well as the collection of necromass and soil samples to a depth of 100 cm. Tree biomass and necromass were estimated using allometric equations. Carbon stocks in tree biomass and roots were calculated using conversion factors, whereas necromass carbon stocks were estimated based on biomass and measured total carbon contents. Soil carbon stocks were determined from total carbon contents and bulk density. The evaluated mangroves stored on average 472.87 ± 128.90 Mg C ha⁻ 1 , with soils representing the dominant carbon pool (87.1% of the total), followed by aboveground biomass, roots, and necromass. Soil carbon stocks increased with depth. Compared to other tropical mangroves, SPIC values fall within the global range and are higher than those reported for other Brazilian sites, underscoring the critical contribution of soils as carbon reservoirs. This study provides one of the few compartmental assessments available for mangroves in Northeastern Brazil, highlighting their relevance as blue carbon ecosystems under anthropogenic pressure.