Coral Symbiodinium Community Composition Across the Belize Mesoamerican Barrier Reef System is Influenced by Host Species and Thermal Variability

• Published in: Microbial ecology Vol. 75; no. 4; pp. 903 - 916
• Main Authors: Baumann, J. H., Davies, S. W., Aichelman, H. E., Castillo, K. D.
• Format: Journal Article
• Language: English
• Published: New York Springer Science + Business Media 01.05.2018; Springer US; Springer Nature B.V
• Subjects: Acidification; Algae; Barrier reefs; Biomedical and Life Sciences; Communities; Community composition; Coral reefs; Corals; Ecology; ENVIRONMENTAL MICROBIOLOGY; Eutrophication; Genetic diversity; Genetic variation; Geoecology/Natural Processes; Identification; Life Sciences; Microbial Ecology; Microbiology; Mineral nutrients; Nature Conservation; Nutrient availability; Nutrients; Ocean acidification; Ocean warming; Offshore; Pseudodiploria strigosa; Siderastrea radians; Siderastrea siderea; Species; Symbiodinium; Symbionts; Symbiosis; Temperature tolerance; Thermal stress; Thermodynamic properties; Water Quality/Water Pollution; Belize; Symbiosis; Environmental variability; Coral; Marine science; Symbiodinium
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-017-1096-6

Reef-building corals maintain a symbiotic relationship with dinoflagellate algae of the genus Symbiodinium, and this symbiosis is vital for the survival of the coral holobiont. Symbiodinium community composition within the coral host has been shown to influence a coral’s ability to resist and recover from stress. A multitude of stressors including ocean warming, ocean acidification, and eutrophication have been linked to global scale decline in coral health and cover in recent decades. Three distinct thermal regimes (highTP, modTP, and lowTP) following an inshore-offshore gradient of declining average temperatures and thermal variation were identified on the Belize Mesoamerican Barrier Reef System (MBRS). Quantitative metabarcoding of the ITS-2 locus was employed to investigate differences and similarities in Symbiodinium genetic diversity of the Caribbean corals Siderastrea siderea, S. radians, and Pseudodiploria strigosa between the three thermal regimes. A total of ten Symbiodinium lineages were identified across the three coral host species. S. siderea was associated with distinct Symbiodinium communities; however, Symbiodinium communities of its congener, S. radians and P. strigosa, were more similar to one another. Thermal regime played a role in defining Symbiodinium communities in S. siderea but not S. radians or P. strigosa. Against expectations, Symbiodinium trenchii, a symbiont known to confer thermal tolerance, was dominant only in S. siderea at one sampled offshore site and was rare inshore, suggesting that coral thermal tolerance in more thermally variable inshore habitats is achieved through alternative mechanisms. Overall, thermal parameters alone were likely not the only primary drivers of Symbiodinium community composition, suggesting that environmental variables unrelated to temperature (i.e., light availability or nutrients) may play key roles in structuring coral-algal communities in Belize and that the relative importance of these environmental variables may vary by coral host species.