Abstract：
Seagrass beds, as highly productive coastal blue carbon ecosystems, not only sustain rich biodiversity and fishery resources but also account for a substantial fraction of global marine organic carbon burial. Sediment microbial communities in seagrass beds are core drivers of carbon, nitrogen and sulfur cycling, and their diversity and composition serve as sensitive indicators of ecosystem health and carbon sink function. However, systematic cross‑regional comparisons of seagrass sediment microbial diversity along the climatic gradient of China’s coastline remain scarce. Here we used 16S rRNA gene amplicon sequencing and metagenomics high‑throughput sequencing to investigate the diversity, community structure and predicted functions of microbiomes from seagrass rhizosphere sediments, sediment cores and adjacent bare‑flat sediments from four representative seagrass habitats spanning temperate to tropical zones: Swan Lake in Shandong, Maowei Sea in Guangxi, Yanzhou Island in Guangdong, and Li’an Lagoon in Hainan. This work aims to 1) characterize the microbial community structures in sediments of different seagrass beds along the Chinese coast, 2) assess their functional diversity to uncover the impact of seagrass species specificity on microbial ecological functions, 3) integrate microbial community composition with sediment chemical indexes, revealing the microbe-environment interaction mechanisms during the degradation and restoration of seagrass beds.
Keywords: Seagrass bed sediments; Microbial diversity; Blue carbon