Sediment Metagenomic Analysis Report within the Campus

Apple snails (*Pomacea canaliculata*), an invasive species, can reshape benthic microbial communities through excretion. We performed shotgun metagenomic sequencing (~10 Gb per sample, DNBSEQ PE150) on nine sediment samples collected along a snail-influence gradient (near-snail, mid-distance, and snail-free groups) near Zhujiajiao Middle School; clean data ratios exceeded 98.5%, confirming reliable quality. Taxonomy was assigned using Kraken2/Bracken2, and MEGAHIT assembly plus CD-HIT clustering yielded 386,545 non-redundant genes from 728,729 predicted CDSs. Near-snail sediments showed higher assembly complexity and enriched organic-matter degraders (*Sorangium cellulosum*, *Anaeromyxobacter*), opportunistic pathogens (*Pseudomonas aeruginosa*, *Klebsiella pneumoniae*), and nitrogen-cycling taxa, while snail-free sediments were dominated by oligotrophic microbes. Alpha diversity did not differ significantly among groups, but NMDS revealed a gradient in community structure. Functional annotation highlighted enrichment of carbohydrate, energy, amino-acid, and xenobiotic-degradation pathways near snails. These results suggest apple snail invasion drives sediment microbial succession, with implications for eutrophication and pathogen-related health risks.