Co‐dynamics of Symbiodiniaceae and bacterial populations during the first year of symbiosis with Acropora tenuis juveniles

Abstract

Interactions between corals and their associated microbial communities (Symbiodiniaceae and prokaryotes) are key to understanding corals' potential for and rate of acclimatory and adaptive responses. However, the establishment of microalgal and bacterial communities is poorly understood during coral ontogeny in the wild. We examined the establishment and co-occurrence between multiple microbial communities using 16S rRNA (bacterial) and ITS2 rDNA (Symbiodiniaceae) gene amplicon sequencing in juveniles of the common coral, Acropora tenuis, across the first year of development. Symbiodiniaceae communities in juveniles were dominated by Durusdinium trenchii and glynnii (D1 and D1a), with lower abundances of Cladocopium (C1, C1d, C50, and Cspc). Bacterial communities were more diverse and dominated by taxa within Proteobacteria, Cyanobacteria, and Planctomycetes. Both communities were characterized by significant changes in relative abundance and diversity of taxa throughout the year. D1, D1a, and C1 were significantly correlated with multiple bacterial taxa, including Alpha-, Deltra-, and Gammaproteobacteria, Planctomycetacia, Oxyphotobacteria, Phycisphaerae, and Rhizobiales. Specifically, D1a tended to associate with Oxyphotobacteria and D1 with Alphaproteobacteria, although these associations may represent correlational and not causal relationships. Bioenergetic modeling combined with physiological measurements of coral juveniles (surface area and Symbiodiniaceae cell densities) identified key periods of carbon limitation and nitrogen assimilation, potentially coinciding with shifts in microbial community composition. These results demonstrate that Symbiodiniaceae and bacterial communities are dynamic throughout the first year of ontology and may vary in tandem, with important fitness effects on host juveniles. K E Y W O R D S

Microbiome dynamics in the tissue and mucus of acroporid corals differ in relation to host and environmental parameters

“…As the microbiome is strongly associated to the coral holobiont, any disturbance in the host-Symbiodiniaceae relationship may have indirect effects on the microbial composition and its response to environmental and physiological factors. Other studies demonstrate the influence of Symbiodiniaceae on the host microbial community and also support the idea that these two components of the coral holobiont are finely tuned (Glasl et al, 2017;Grottoli et al, 2018;Littman, Bourne & Willis, 2010;Quigley et al, 2019). In the present study, Endozoicimonaceae were strongly positively correlated with the Symbiodiniaceae density in the tissue of A. tenuis and negatively correlated with NO − 2 /NO − 3 in A. millepora (see Fig.…”

Peer Review #1 of "Microbiome dynamics in the tissue and mucus of acroporid corals differ in relation to host and environmental parameters (v0.1)"

“…Other studies demonstrate the influence of Symbiodiniaceae on the host microbial community and also support the idea that these two components of the coral holobiont are finely tuned (Glasl et al, 2017;Grottoli et al, 2018;Littman, Bourne & Willis, 2010;Littman, Willis & Bourne, 2009b;Quigley et al, 2019). In the present study, Endozoicimonaceae were strongly positively correlated with the Symbiodiniaceae density in the tissue of A. tenuis and negatively correlated with NO 2 -/NO 3in A. millepora (see Figure 5).…”

“…Manuscript to be reviewed harbors photosymbiotic dinoflagellates (family Symbiodiniaceae), that can provide up to 100% of energy required by their coral host (Muller-Parker, D'Elia & Cook, 2015). The Symbiodiniaceae community has been shown to vary in tandem with the bacterial community in early life stages of corals (Quigley et al, 2019) and this may be caused by the release of complex organic molecules such as the organosulfur compound dimethylsulfoniopropionate (DMSP; Bourne et al, 2013;Frade et al, 2016b). The coral tissue microbiome is mostly represented by bacteria belonging to the phyla Proteobacteria and Actinobacteria.…”

The Prokaryotic Microbiome of Acropora digitifera is Stable under Short-Term Artificial Light Pollution

“…In our study, we found that members of Lachnospiraceae, Rhodobacterales, and Caulobacterales, which include known diazotrophs [ 74 , 75 , 76 , 77 , 78 , 79 ], were relatively more abundant in corals subjected to light at night. These bacterial groups have also been found to co-occur with dinoflagellate symbionts of corals [ 80 , 81 ]. It is possible that the higher abundance of symbiont-associated microbes in the corals under ALAN treatment is linked to the greater abundance and activity of the dinoflagellate symbionts.…”