Repopulation of Zooxanthellae in the Caribbean Corals Montastraea annularis and M. faveolata following Experimental and Disease-Associated Bleaching

• Published in: The Biological bulletin (Lancaster) Vol. 201; no. 3; pp. 360 - 373
• Main Authors: Toller, W. W., Rowan, R., Knowlton, N.
• Format: Journal Article
• Language: English
• Published: United States Marine Biological Laboratory 01-12-2001; University of Chicago Press
• Subjects: Animals; Base Sequence; Biology; Bleaching; Cnidaria - parasitology; Coral reefs; Corals; Dinoflagellates; Dinoflagellida - chemistry; Dinoflagellida - genetics; Dinoflagellida - growth & development; Disease; DNA, Protozoan - chemistry; DNA, Protozoan - genetics; DNA, Protozoan - isolation & purification; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; DNA, Ribosomal - isolation & purification; Environmental aspects; Genotypes; Habitats; Irradiance; Lesions; Light; Marine; Molecular Sequence Data; Montastraea annularis; Montastraea faveolata; Panama; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Scleractinia; Symbiodinium; Symbiosis; Symbiosis and Parasitology; Taxa; Tissue samples; Tissues; Panama; United States; Caribbean Sea; ASW, Caribbean Sea; RFLP, restriction fragment length polymorphism; srDNA, small subunit ribosomal RNA gene; YBD, yellow-blotch disease
• ISSN: 0006-3185; 1939-8697
• DOI: 10.2307/1543614

Caribbean corals of the Montastraea annularis species complex associate with four taxa of symbiotic dinoflagellates (zooxanthellae; genus Symbiodinium) in ecologically predictable patterns. To investigate the resilience of these host-zooxanthella associations, we conducted field experiments in which we experimentally reduced the numbers of zooxanthellae (by transplanting to shallow water or by shading) and then allowed treated corals to recover. When depletion was not extreme, recovering corals generally contained the same types of zooxanthellae as they did prior to treatment. After severe depletion, however, recovering corals were always repopulated by zooxanthellae atypical for their habitat (and in some cases atypical for the coral species). These unusual zooxanthellar associations were often (but not always) established in experimentally bleached tissues even when adjacent tissues were untreated. Atypical zooxanthellae were also observed in bleached tissues of unmanipulated Montastraea with yellow-blotch disease. In colonies where unusual associations were established, the original taxa of zooxanthellae were not detected even 9 months after the end of treatment. These observations suggest that zooxanthellae in Montastraea range from fugitive opportunists and stress-tolerant generalists (Symbiodinium A and E) to narrowly adapted specialists (Symbiodinium B and C), and may undergo succession.