Background: Although the term holobiont has been popularized in corals with the advent of the hologenome theory of evolution, the underlying concepts are still a matter of debate. Indeed, the relative contribution of host and environment and especially thermal regime in shaping the microbial communities should be examined carefully to evaluate the potential role of symbionts for holobiont adaptation in the context of global changes. We used the sessile, long-lived, symbiotic and environmentally sensitive reef-building coral Pocillopora damicornis to address these issues.
Results: We sampled Pocillopora damicornis colonies corresponding to two different mitochondrial lineages in different geographic areas displaying different thermal regimes: Djibouti, French Polynesia, New Caledonia, and Taiwan. The community composition of bacteria and the algal endosymbiont Symbiodinium were characterized using high-throughput sequencing of 16S rRNA gene and internal transcribed spacer, ITS2, respectively. Bacterial microbiota was very diverse with high prevalence of Endozoicomonas, Arcobacter, and Acinetobacter in all samples. While Symbiodinium sub-clade C1 was dominant in Taiwan and New Caledonia, D1 was dominant in Djibouti and French Polynesia. Moreover, we also identified a high background diversity (i.e., with proportions < 1%) of A1, C3, C15, and G Symbiodinum sub-clades. Using redundancy analyses, we found that the effect of geography was very low for both communities and that host genotypes and temperatures differently influenced Symbiodinium and bacterial microbiota. Indeed, while the constraint of host haplotype was higher than temperatures on bacterial composition, we showed for the first time a strong relationship between the composition of Symbiodinium communities and minimal sea surface temperatures.
Conclusion: Because Symbiodinium assemblages are more constrained by the thermal regime than bacterial communities, we propose that their contribution to adaptive capacities of the holobiont to temperature changes might be higher than the influence of bacterial microbiota. Moreover, the link between Symbiodinium community composition and minimal temperatures suggests low relative fitness of clade D at lower temperatures. This observation is particularly relevant in the context of climate change, since corals will face increasing temperatures as well as much frequent abnormal cold episodes in some areas of the world.
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http://dx.doi.org/10.1186/s40168-018-0423-6 | DOI Listing |
Mar Environ Res
January 2025
School of Marine Science and Engineering, Collaborative Innovation Center of Marine Science and Technology, Hainan University, 570228, Haikou, China. Electronic address:
The scleractinian corals conduct various responses upon heat stress such as bleaching and tissue loss, and colonies from the same coral species can conduct differential physiological activities with the biochemical basis unknown. In the present study, factors that influence the heat stress responses in coral Pocillopora damicornis were investigated. It was observed that P.
View Article and Find Full Text PDFPLoS One
January 2025
Institute for Global Ecology, Florida Institute of Technology, Melbourne, Florida, United States of America.
Marine heatwaves are increasing in intensity and frequency however, responses and survival of reef corals vary geographically. Geographical differences in thermal tolerance may be in part a consequence of intraspecific diversity, where high-diversity localities are more likely to support heat-tolerant alleles that promote survival through thermal stress. Here, we assessed geographical patterns of intraspecific genetic diversity in the ubiquitous coral Pocillopora damicornis species complex using 428 sequences of the Internal Transcribed Spacer 2 (ITS2) region across 44 sites in the Pacific and Indian Oceans.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
School of Marine Science and Engineering, Hainan University, Haikou 570228, China. Electronic address:
Antibiotics threaten scleractinian corals, but their accumulation patterns and physiological effects on corals in natural reefs remain unclear. This study investigated antibiotic occurrence in seawater and two coral species, Galaxea fascicularis and Pocillopora damicornis, and explored the physiological effects of bioaccumulated antibiotics in a fringing reef of the South China Sea. Nineteen antibiotic components were detected in seawater, with total antibiotic concentrations (ΣABs) ranging from 17.
View Article and Find Full Text PDFMol Ecol
January 2025
Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Corals residing in habitats that experience high-frequency seawater pCO variability may possess an enhanced capacity to cope with ocean acidification, yet we lack a clear understanding of the molecular toolkit enabling acclimatisation to environmental extremes or how life-long exposure to pCO variability influences biomineralisation. Here, we examined the gene expression responses and micro-skeletal characteristics of Pocillopora damicornis originating from the reef flat and reef slope of Heron Island, southern Great Barrier Reef. The reef flat and reef slope had similar mean seawater pCO, but the reef flat experienced twice the mean daily pCO amplitude (range of 797 v.
View Article and Find Full Text PDFPLoS One
November 2024
Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States of America.
Long-term monitoring of individual coral colonies is important for understanding variability between and within species over time in the context of thermal stress. Here, we analyze an 11-year time series of permanent benthic photoquadrats taken on Palmyra Atoll, central Pacific, from 2009 to 2019 to track the growth (i.e.
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