Fluctuations in sediment blue carbon density associated with land use changes and mangrove distribution along the semiarid, rapidly industrializing coastline of India.

Mangrove ecosystems can sequester blue carbon, yet anthropogenic activities increasingly threaten it's habitat and carbon storage capacity. The blue carbon sequestration potential of mangroves is an underexplored avenue in climate change science. The sustainable development goal (SDG)13 strongly emphasizes the need to reduce carbon emissions, whereas SDG 14 focuses on conserving coastal and marine ecosystems Understanding mangroves' essential ecosystem services, primarily 'blue carbon', distributed in different climatic zones is being prioritized by academics and policymakers. The Indian subcontinent is endowed with mangroves along its different coasts; however, the semiarid mangrove patches only exist in the western Indian district of Kachchh and are largely, unexplored. In our present study, we conducted a comprehensive assessment of sediment carbon stocks across multiple sites subjected to varying degrees of industrialization, urbanization, and agricultural encroachment along the coastline of Kachchh mangroves. Sediment cores were obtained from mangrove areas categorized as pristine, moderately impacted, and heavily industrialized to measure organic carbon content and assess its relationship with Normalized Difference Vegetation Index (NDVI). The approach aimed to evaluate variations in the blue carbon pool concerning different land use patterns. Seasonal sampling of mangrove sediments was conducted in both anthropogenically impacted and unaffected zones, with the resulting data analyzed using a three-way ANOVA (analysis of variance) within GLM (general linear model). A relationship was observed between anthropogenic activities and values of organic carbon density (OCD) and blue carbon pool. Respite of Mangrove restoration activities, the human intervention led to lower OCD values (1.2 % and 1.4 %, S.E. = ±.56) near industrial activity zones. This calls for combined efforts from all sectors to restore these fragile ecosystems in the region. The contributing role of mangroves as blue carbon sink is important in the fight against climate change.