Summary The giant barrel sponge, X estospongia muta , is a high microbial abundance sponge found on Caribbean coral reefs along shallow to mesophotic depth gradients where multiple abiotic factors change with depth. Sponges were collected along a depth gradient at L ittle C ayman ( LC ) and Lee Stocking Island ( LSI ), and the microbiome of these samples was analysed using 16 S r RNA amplicon sequencing. Statistically signific...