Assessment of coral reef connectivity in improved organic carbon storage of seagrass ecosystems in Palk Bay, India

The increase in climate-related extreme events and ecosystem degradation demands consistent and sustainable climate mitigation efforts. Seagrass playing a key role in nature-based carbon sequestration mitigation strategy. Here, we investigated the role of coral reef connectivity in blue carbon dynamics with seagrass meadows with coral reef connectivity (SC areas) and without coral reef connectivity (SG areas) in Palk Bay, India. The high sediment organic carbon was recorded in SC areas (90.26 ± 25.68 Mg org.C/ha) and lower in SG areas (66.96 ± 12.6 Mg org.C/ha). The maximum above-ground biomass (AGB) was recorded in Syringodium isoetifolium (35.43 ± 8.50) in SC areas and the minimum in Halophila ovalis (7.59 ± 0.90) in SG areas, with a similar trend observed in below-ground biomass (BGB). Our findings highlight the importance of coral reefs in enhancing the blue carbon potential of seagrass ecosystems and underscore the need for integrated conservation and restoration strategies for coral reefs and seagrasses. •Study reveals the site-specific habitat for SC & SG of carbon storage in Palk Bay•The mean above-ground biomass of Syringodium isoetifolim was 35.43 ± 8.50 g dwt/m2.•The sediment organic carbon stock of Cymodocea rotundata was 84.79 ± 1.37 Mg org.C/ha•Coral reef–seagrass habitat identified as potential climate change mitigation hotspot