How Deep Ocean Conditions Shape Coral Microbiomes

Jim Crocker
11th June, 2024

How Deep Ocean Conditions Shape Coral Microbiomes

Image Source: Natural Science News, 2024

Key Findings

  • Researchers from Lehigh University studied four octocoral species in the deep waters of the northern Gulf of Mexico
  • The microbiomes of these corals varied significantly between species and were influenced by environmental factors like depth and geographic location
  • The coral's genotype also played a crucial role in shaping its microbiome, supporting the concept of phylosymbiosis
Coral reefs are vital ecosystems known for their biodiversity and productivity. Yet, the intricate relationships between corals and their associated microbial communities are still not fully understood, especially for corals inhabiting deep-sea environments. A recent study conducted by researchers from Lehigh University[1] sheds light on the variability of coral-associated microbiomes across different coral species and environmental conditions in the deep waters of the northern Gulf of Mexico. The study focused on four octocoral species: Muricea pendula, Swiftia exserta, Callogorgia delta, and Paramuricea biscaya. These species were sampled extensively across their depth ranges (53–2224 meters) and geographic locations (over 680 meters) to characterize their microbiomes using 16S rRNA gene metabarcoding. This method allows for the identification and comparison of bacterial communities present in the coral samples. Additionally, the researchers used RAD-sequencing to examine the influence of the host coral’s genotype on its microbiome. Previous studies have indicated that coral microbiomes are highly compartmentalized and influenced by both host and environmental factors. For instance, research on scleractinian corals has shown that their microbial communities differ significantly between the mucus, tissue, and skeleton, with each compartment hosting distinct bacterial and archaeal communities[2]. This compartmentalization is also reflected in the evolutionary assembly of coral microbiomes, suggesting a deep-rooted relationship between corals and their microbial partners. In the current study, the researchers found significant variability in the microbiomes of the four octocoral species, both between and within species. Environmental factors such as depth and geographic location played a crucial role in shaping these microbial communities. This finding aligns with earlier research that demonstrated the influence of environmental conditions on the diversity and distribution of coral-associated Archaea[3]. For example, different coral genera from the Gulf of Eilat and Heron Island were found to host distinct archaeal communities, with a notable presence of ammonia-oxidizing archaea, which contribute to nitrogen cycling in the coral holobiont. The study also highlighted the functional consequences of microbiome variability on the host corals. Variations in microbial communities can impact coral health, resilience, and disease susceptibility. This is particularly important in the context of deep-sea corals, which are less studied compared to their shallow-water counterparts. Understanding the microbiome composition of these deep-sea corals can provide insights into their adaptation mechanisms and responses to environmental stressors. Furthermore, the researchers discovered that the coral's genotype significantly influenced its associated microbiome. This finding supports the concept of phylosymbiosis, where the composition and richness of the microbiome reflect the phylogeny of the host coral[2]. Such host-microbe interactions have been observed in various coral species, indicating that the evolutionary history of corals plays a role in shaping their microbial communities. Incorporating these findings into the broader context of coral reef microbiology, it becomes evident that microbial communities are integral to coral health and ecosystem function. Both prokaryotic and eukaryotic microbes contribute to biogeochemical cycles, primary productivity, and disease dynamics within coral reefs[4]. While the current study focused on bacterial communities, it is essential to consider the roles of eukaryotic microbes and viruses in these complex interactions. Viruses, for example, have been linked to coral mortality and reef ecosystem decline, influencing microbial community dynamics and biogeochemical cycling[5]. In summary, the study by Lehigh University researchers provides valuable insights into the variability and functional consequences of coral-associated microbiomes in deep-sea environments. By characterizing the microbiomes of four octocoral species across different depths and locations, the researchers demonstrated the significant influence of environmental factors and host genotype on microbial community composition. These findings contribute to our understanding of coral-microbe interactions and highlight the importance of considering microbial communities in coral conservation and management efforts.

EnvironmentEcologyMarine Biology

References

Main Study

1) Coral microbiomes are structured by environmental gradients in deep waters

Published 10th June, 2024

https://doi.org/10.1186/s40793-024-00579-0

Related Studies

2) Coral-associated bacteria demonstrate phylosymbiosis and cophylogeny.

https://doi.org/10.1038/s41467-018-07275-x

3) Global distribution and diversity of coral-associated Archaea and their possible role in the coral holobiont nitrogen cycle.

https://doi.org/10.1111/j.1462-2920.2008.01718.x

4) The Other Microeukaryotes of the Coral Reef Microbiome.

https://doi.org/10.1016/j.tim.2017.06.007

5) Virus-host interactions and their roles in coral reef health and disease.

https://doi.org/10.1038/nrmicro.2016.176


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