Estimation of Mangrove Blue Carbon in Three Semi-arid Lagoons in the Gulf of California

Blue carbon ecosystems are recognized as natural climate solutions due to their capacity to store carbon (C) in the vegetation and soil. Thus, the extent of such role by mangrove ecosystems has raised interest in the scientific community. Mangrove carbon stock above ground biomass is higher in humid tropical areas than in dry subtropical ones. However, a lack of information persists when it comes to the belowground C. This research aimed to determine the carbon stock in relation to total mangrove biomass in three semi-arid coastal lagoons in the Gulf of California, Mexico. Different methods were used, tree structure and pneumatophore measurements, litter traps, root and production cores; along with measurements of physicochemical parameters in sediment in surface and interstitial water. Mean carbon in the total mangrove biomass was 54.1 MgCorg·ha⁻¹, with a maximum of 102.1 ± 14.2 MgCorg·ha⁻¹ at the Lobos site. In arid areas, mangroves are characterized by larger amounts of belowground biomass associated with environmental factors such as pH, redox potential, and temperature, leading to a high C_org content belowground. Root production are high, enhancing the efficiency of belowground C_org storage related to the life cycle of roots (turnover). The presence of Conocarpus erectus (L), a new record of the distribution limit of the species in the Gulf of California (Lobos), attained the highest values of structural development, litter-based primary productivity, and belowground root production and biomass. Therefore, this species is recommended for restoration (reforestation), given its high primary productivity that stabilizes the coastline and increases carbon storage dynamics.