Variance Matters: Individual Differences and Their Consequences for Natural Selection Within and Among Coral Holobionts

The changing climate is altering marine communities at an alarming rate. Current predictions regarding how warming oceans will transform coral reef assemblages place great emphasis on the average responses of coral colonies to environmental shifts, while often ignoring outlier responses and variation within species. Additionally, the vast complexity of organismal interactions within a single coral colony-including the host genotype, the population of eukaryotic photosymbionts, and a consortium of bacteria, archaea, fungi, and viruses- makes the “individual” coral holobiont a multi-tiered unit with many levels upon which natural selection can operate. For a given coral species, only the most resilient combinations of symbiotic partners may survive, grow, and reproduce. As the environment becomes more extreme, these outliers will disproportionately contribute to future reef communities. Thus, there is much to be learned from explicitly examining outlier colony responses and selection at the unit of the coral holobiont.

This Research Topic aims to give greater consideration to intraspecific variation among individual coral colonies and the significance of this ecophysiological diversity for the long-term survival of coral species. We welcome submissions documenting variable responses of coral holobionts within and across habitats, as well as contributions examining the sources of this variation (genetics, symbiotic associations, environmental history, etc.) and their implications for the future of coral reef ecosystems.