<p>Driven by the essential role of blue carbon ecosystems in mitigating climate change and by scarce regional data, here we aim to quantify carbon sequestration rates and storage in a Moroccan coastal vegetated ecosystem over time using nuclear approaches. The carbon stocks recorded over the past 60 years ranged from 1.35 to 11.07 Mg C_org ha⁻¹ in Merja Kahla and from 3.55 to 54.48 Mg C_org ha⁻¹ and from 3.57 to 104.58 Mg C_org ha⁻¹ in two cores from Merja Zerga. The highest carbon accumulation rates were observed in the top 5 cm of sediment cores, ranging from 14.60 to 53.08 g OC m⁻² yr⁻¹, suggesting a noticeable increase in recent years. These findings highlight the need to integrate blue carbon ecosystems into national policies as nature-based solutions for mitigating climate change and for enhancing the management and conservation of coastal and marine resources threatened by human activities.</p>