Exceptional biomass, deep organic-rich soils, and strong hydrological and sedimentary controls shape mangrove blue carbon dynamics along the Amazon coast. Carbon stocks accumulate across above- and belowground compartments and are dominated by organic carbon soil formed under persistent anoxic conditions. Carbon fluxes reflect interactions among photosynthesis, respiration, litterfall, decomposition, and gas exchange, all of which are sensitive to salinity, hydrology, and climatic anomalies. Climate change intensifies these pressures by altering sea-level trends, sediment supply, rainfall regimes, and the frequency of extreme events, with consequences for forest structure, sediment deposition, carbon burial, and greenhouse gas emissions. Strengthening blue carbon assessments requires improved long-term monitoring, integration of geomorphological context, and engagement with traditional communities whose knowledge enhances ecological understanding and governance. Advances in remote sensing, allometric modelling, soil biogeochemistry, and community-based monitoring contribute to more accurate carbon accounting and support policy frameworks aimed at conservation, adaptation, and climate mitigation in Amazonian mangrove systems.