Sample-based rarefaction curves of ASV diversity detected in 18S rRNA (V1–V3) gene amplicon analysis of Palmyra Atoll. Sample types include 100-500 μm sediment, 500 μm -2 mm sediment, sessile material scrapings, and reef water. Given the uneven sampling depths, for some comparative analyses samples were later rarefied to even sequencing depth. Numbers indicate sampling site as shown in Fig. 1.