Meeting Abstract
Corals from more variable environments tend to fare better under thermal stress when compared to their counterparts from more stable environments. Marine environments exhibiting more or less thermal variability are ubiquitous and even reef zones within the same reef can display divergent thermal profiles. These reef zones offer an opportunity to investigate the role that thermal variability plays in coral resilience and may shed light on how best to manage reefs under climate change. Studies have demonstrated that multiple members of the coral holobiont (the coral host and its associated microorganisms) play a role in a coral’s capacity to cope with reef zone differences, however, few studies have contrasted more than two holobiont partners across these environments. Here, we profiled the genetic structure of the coral host, Acropora hyacinthus, along with the community compositions of its resident algal symbionts and microbiome from three paired inshore (more variable) and offshore (more stable) reef zones in French Polynesia. 2b-RAD sequencing determined that this broadcast spawning coral exhibited complete panmixia across all reefs regardless of environmental characteristics. In contrast, using ITS2 metabarcoding, we consistently found that algal symbiont communities within offshore corals had higher alpha diversity. In addition, 16S metabarcoding revealed subtle differences in microbiome taxa between reef zones. Our results from investigating this tripartite symbiosis support previous findings suggesting that microbial partners play a role in the ability of their coral hosts to cope with environmental variation. As oceans continue to warm, contrasting how different holobiont partners vary across reef environments may help illuminate coral resilience in a changing world.
