Impacts of nursery-based propagation and out-planting on coral-associated bacterial communities

Bacterial communities associated with corals out-planted on the Great Barrier Reef are inherently dynamic over space and time

“…To examine differences in coral-associated bacterial communities among coral fragments out-planted at each reef site with contrasting characteristics, we performed a transplantation experiment using the coral species A. millepora. This species is routinely grown in coral nurseries and used for out-planting on the GBR (e.g., Howlett et al 2022) and exhibits microbiome variability over time and space via these propagation steps at Opal Reef (Strudwick et al 2022).…”

“…After sampling, all fragments were returned to the operations vessel (Wavelength IV) in sterile zip-lock bags within 30-50 min, placed into sterile 15 mL falcon tubes and preserved by total submersion in RNAlater. All samples were subsequently held at ambient temperature for 6 days during transportation from the study site to the laboratory for processing (as per Strudwick et al 2022). Once in the laboratory, RNAlater was thoroughly removed from 15 mL falcon tubes using an adjustable pipette with sterile tips, after which samples were preserved at − 80°C for 1-11 months until DNA was extracted.…”

“…Bacterial community composition of out-planted corals only signi cantly differed for Mojo vs Rayban and Mojo vs Sandbox at 1.5 months (T 1.5m ) (PERMANOVA Bray−curtis , F = 1.346, p adj = 0.048, df = 1; F = 1.232, p adj = 0.048, df = 1 respectively). Differences between out-planted fragments were primarily explained by higher relative abundance (RA) at Sandbox and Rayban compared to Mojo of two ASVs from the genus Endozoicomonas (one of which was from the 'core' microbiome characterised in donor colonies at T F ), as well as a lower relative abundance at Sandbox and Rayban of ASVs from the Lactobacillus, Ruegeria, Erythrobacter and Pseudovibrio genera compared to Mojo (SIMPER, and (Strudwick et al 2022) and it has been proposed that these changes are driven by exposure to novel environmental conditions between propagation sites (Strudwick et al 2022). Even so, to date there has been little quanti cation and comparison of long-term out-plant survival and associated bacterial community composition across reef sites with contrasting environmental conditions on the GBR.…”

“…Increasingly frequent and intense anthropogenic disturbances threaten the persistence of tropical coral reefs and hence the wealth of ecological, economic, social and heritage values they provide (Hughes et Strudwick et al 2022). For example, we recently demonstrated that bacterial communities of some species (A. millepora), but not others (Pocillopora verrucosa) can undergo signi cant restructuring during long-term nursery propagation and subsequent early out-planting (1 day-1 month) (Strudwick et al 2022).…”

Geographically driven differences in microbiomes of Acropora cervicornis originating from different regions of Florida’s Coral Reef

“…Host identity is known to have greater control on microbiome composition than temporal differences ( Dunphy et al, 2019 ), however, there is still evidence of temporal variability in coral microbiomes ( Epstein et al, 2019 ). Stability of coral microbiomes over time or when transplanted is known to be a species-specific response ( Roitman et al, 2020 ; Deignan & McDougald, 2021 ; Dunphy, Vollmer & Gouhier, 2021 ; Strudwick et al., 2022 ). In a previous study of microbiome shifts resulting from translocation, a non-Caribbean Acroporid coral, A. hemprichii, experienced significant microbiome restructuring when moved across sites in the Red Sea ( Ziegler et al, 2019 ).…”