Coral associated eukaryote
For symbiotic algae typing, a multicopy genetic marker commonly used to assess algae diversity was performed. 18S rRNA genes of eukaryotes were amplified using primers 3NDF and V4-euk-R2R with concatenated Illumina sequencing adapters. The thermal conditions for algae amplicon PCRs were began with a 5 min denaturing step at 94C, followed by 30 cycles of 95C for 40 s, 50C for 30 s, and 72C for 2 min. The final cycle was an extension at 72C for 10 min.