The coral microbiome can therefore serve as a proxy for environmental variation when environment cannot be measured directly, such as in ancientDNA studies.

We also find that the A. millepora microbiome is predictive of environmental variation, and that Endozoicomonas variation is low during bleaching, consisitent with previous findings.

Here, we find that dominant photosymbiont identity, host genetics, and environmental variation, but not bleaching status, predicts the microbiome of Acropora millepora in the Central Great Barrier Reef. The microbiome correlates with dominant photosymbiont identity even during bleaching events.