Generating blue carbon credits through conservation of Posidonia oceanica: experience from the LIFE SeaForest project

Introduction Posidonia oceanica meadows are key blue carbon ecosystems in the Mediterranean Sea, storing substantial carbon within biomass and underlying sediments. Unregulated recreational anchoring contributes to meadow degradation and may compromise the retention of previously stored carbon. The LIFE SeaForest project (LIFE17 CCM/IT/000121) aimed to reduce carbon losses associated with P. oceanica degradation through integrated management, monitoring, conservation, and restoration actions across three Mediterranean protected coastal areas. Methods A comprehensive ex-ante accounting framework was developed to estimate anchoring-related potential carbon-stock losses, expressed in CO 2 -equivalent units, under baseline (business-as-usual) and project scenarios. The methodology considered vessel-size classes and substrate categories associated with P. oceanica (rocky, sandy, and degraded dead matte substrates). Project actions included environmentally friendly mooring systems, sustainable anchoring management plans, and regulation of recreational boating through a dedicated digital user platform. Results Over the ten-year accounting period, cumulative Net Emission Reductions (NERs) exceeded 5,000 tCO 2 eq across the three project areas. This value represents net avoided potential carbon-stock loss, rather than directly quantified atmospheric CO 2 emissions, and identifies a potential SeaForest credit volume subject to monitoring, verification, and certification. Discussion The proposed framework represents one of the first structured ex-ante approaches for estimating potential blue carbon credits from conservation measures that reduce anchoring impacts in Mediterranean P. oceanica meadows. Although further validation and long-term monitoring are needed, the SeaForest approach provides a potentially replicable framework for blue carbon initiatives, sustainable coastal management, and climate-mitigation policies in the Mediterranean region.