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Local vs. site-level effects of algae on coral microbial communities

Cite this dataset

Briggs, Amy; Brown, Anya; Osenberg, Craig (2021). Local vs. site-level effects of algae on coral microbial communities [Dataset]. Dryad.


Microbes influence ecological processes, including the dynamics and health of macro-organisms and their interactions with other species.  In coral reefs, microbes mediate negative effects of algae on corals when corals are in contact with algae.  However, it is unknown whether these effects extend to larger spatial scales, such as at sites with high algal densities.  We investigated how local algal contact and site-level macroalgal cover influenced coral microbial communities in a field study at two islands in French Polynesia, Mo’orea and Mangareva.  At 5 sites at each island, we sampled prokaryotic microbial communities (microbiomes) associated with corals, macroalgae, turf algae, and water, with coral samples taken from individuals that were isolated from or in contact with turf or macroalgae.  Algal contact and macroalgal cover had antagonistic effects on coral microbiome alpha and beta diversity.  Additionally, coral microbiomes shifted and became more similar to macroalgal microbiomes at sites with high macroalgal cover and with algal contact, although the microbial taxa that changed varied by island.  Our results indicate that coral microbiomes can be affected by algae outside of the coral’s immediate vicinity, and local- and site-level effects of algae can obscure each other’s effects when both scales are not considered. 


Microbial samples were collected in the field, DNA was extracted, and V4 region of the 16S rRNA gene was amplified and sequenced on an Illumina MiSeq platform.  We used the DADA2 bioinformatics pipeline to infer amplicon sequence variants (ASVs) and to assign taxonomy using the Silva reference database (v. 132).  Microbial community analyses (diversity, community composition, etc.) were performed using phyloseq package in R.

Usage notes

Only samples with a read depth > 100 were uploaded and used for analyses.


University of Georgia, Award: Small Grants Program, Odum School of Ecology

University of Florida, Award: John J. and Katherine C. Ewel Fellowship