<![CDATA[Seagrass ecosystems are part of the components of tropical coastal ecosystems that have high ecological and economic functions. They provide habitat for marine biota, act as sediment stabilizers, and are very effective blue carbon storage. This study aims to analyze the structure of seagrass communities in the waters of Sembilan Island, Sinjai Regency, South Sulawesi. Data collection was conducted at six stations using quadrat transect and line transect methods to identify species and calculate ecological indices. These indices include Shannon-Wiener Diversity, Pielou Evenness, and Simpson Dominance. The identification results showed that there were seven seagrass species, namely Enhalus acoroides, Thalassia hemprichii, Syringodium isoetifolium, Cymodocea rotundata, Halodule pinifolia, Halophila minor, and Halophila ovalis. The diversity index value was 1.579 (moderate category), uniformity 0.811 (high), and dominance 0.244 (low), describing a relatively stable and ecologically balanced community. Inter-station correlation analysis showed r values ranging from 0.89 to 1.00, indicating high spatial homogeneity and strong ecological connectivity between observation sites. The resulting community structure is a combination of long-lived climax species (E. acoroides, T. hemprichii) and short-lived pioneer species (H. pinifolia, and H. ovalis), which together maintain regeneration dynamics and ecosystem function. These findings indicate that the seagrass meadows on Sembilan Island are healthy, stable, and functioning optimally as a blue carbon ecosystem, playing a crucial role in storing carbon, stabilizing sediments, and supporting coastal resilience to the impacts of climate change.]]>
