*3.4. Analysis of OTUs within Genus Level*

We further classified and compared the top best enriched operational taxonomic units found between the samples. The heat map represents the distribution of taxa using a contig LCA algorithm, finding a single consensus taxonomic entity for all features on each individual sequence. This shows that the genera *Candidatus, Eubacterium, Flavobacterium, Nitrospira*, *Plactomyces*, *Prolixibacter, Terrimonas*, *Bifidobacterium* are abundant in healthy and bleached *L. baikalensis* samples. Whereas in *B. intermedia* (bleached) samples, the genera *Coptotermes*, *Gemmatimonas, Halomonas*, *Opitutus* are found to be abundant (Figure 4a). More than 15 genera from healthy and nine genera from bleached samples are uniquely found in *L. baikalensis* (Figure 4b) whereas in *B. intermedia*, 23 common and 27 unique genera are found in both healthy and bleached samples (Figure 4c).

**Figure 4.** Top hits operational taxonomic units comparison based on genus-level for selected healthy and bleached sponges. (**a**) The heat map represents the abundances of annotations of taxonomic richness and evenness on a log scale. (**b**,**c**) The Venn diagram represents the common and unique genus found in the samples.
