Microbial Ecology

, Volume 60, Issue 1, pp 250–263

The Relative Significance of Host–Habitat, Depth, and Geography on the Ecology, Endemism, and Speciation of Coral Endosymbionts in the Genus Symbiodinium

  • J. Christine Finney
  • Daniel Tye Pettay
  • Eugenia M. Sampayo
  • Mark E. Warner
  • Hazel A. Oxenford
  • Todd C. LaJeunesse
Host Microbe Interactions

DOI: 10.1007/s00248-010-9681-y

Cite this article as:
Finney, J.C., Pettay, D.T., Sampayo, E.M. et al. Microb Ecol (2010) 60: 250. doi:10.1007/s00248-010-9681-y

Abstract

Dinoflagellates in the genus Symbiodinium are among the most abundant and important group of eukaryotic microbes found in coral reef ecosystems. Recent analyses conducted on various host cnidarians indicated that Symbiodinium assemblages in the Caribbean Sea are genetically and ecologically diverse. In order to further characterize this diversity and identify processes important to its origins, samples from six orders of Cnidaria comprising 45 genera were collected from reef habitats around Barbados (eastern Caribbean) and from the Mesoamerican barrier reef off the coast of Belize (western Caribbean). Fingerprinting of the ribosomal internal transcribed spacer 2 identified 62 genetically different Symbiodinium. Additional analyses of clade B Symbiodinium using microsatellite flanker sequences unequivocally characterized divergent lineages, or “species,” within what was previously thought to be a single entity (B1 or B184). In contrast to the Indo-Pacific where host-generalist symbionts dominate many coral communities, partner specificity in the Caribbean is relatively high and is influenced little by the host’s apparent mode of symbiont acquisition. Habitat depth (ambient light) and geographic isolation appeared to influence the bathymetric zonation and regional distribution for most of the Symbiodinium spp. characterized. Approximately 80% of Symbiodinium types were endemic to either the eastern or western Caribbean and 40–50% were distributed to compatible hosts living in shallow, high-irradiance, or deep, low-irradiance environments. These ecologic, geographic, and phylogenetic patterns indicate that most of the present Symbiodinium diversity probably originated from adaptive radiations driven by ecological specialization in separate Caribbean regions during the Pliocene and Pleistocene periods.

Supplementary material

248_2010_9681_MOESM1_ESM.doc (102 kb)
Supplementary Table S1Genbank accession numbers for ITS2 rDNA and microsatellite flanker sequences for ecologically distinctive clade B Symbiodinium. (DOC 102 kb)
248_2010_9681_MOESM2_ESM.doc (81 kb)
Supplementary Table S2Genbank accession numbers for ITS2 rDNA sequences for ecologically distinctive clade C Symbiodinium. (DOC 81 kb)
248_2010_9681_MOESM3_ESM.doc (39 kb)
Supplementary Table S3Symbiodinium “Clade” prevalence among host genera according to region surveyed and the diversity of “types” found within each clade. Percentages add to greater than 100 because many host taxa can associate with representatives from two or more clades. (DOC 39 kb)
248_2010_9681_Fig6_ESM.jpg (823 kb)
Supplementary Figure 1

Supplementary Figure 1. Symbiont diversities from Barbados and Belize identified from host communities dwelling in a,d) shallow (≤ 5 m), b,e) intermediate (> 5 m to ≤ 10 m), and c,f) deep (> 10 m) habitats. For each environment, the number of host genera with which a particular symbiont potentially associates (presence/absence) is provided on the y-axis. Bars in the graph representing symbionts that were identified from shallow and sometimes intermediate depths are shaded in orange, symbionts found in deep-dwelling colonies and sometimes at intermediate depths are shaded in black. Bars with black outlines indicate no apparent depth constraints are evident for that particular symbiont. The total number of host genera surveyed at each depth in each region is given in parentheses.

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • J. Christine Finney
    • 1
  • Daniel Tye Pettay
    • 2
  • Eugenia M. Sampayo
    • 2
  • Mark E. Warner
    • 3
  • Hazel A. Oxenford
    • 1
  • Todd C. LaJeunesse
    • 2
  1. 1.Centre for Resource Management and Environmental Studies (CERMES)University of the West IndiesCave Hill CampusBarbados
  2. 2.Department of BiologyPennsylvania State UniversityUniversity ParkUSA
  3. 3.College of Earth, Ocean, and EnvironmentUniversity of DelawareLewesUSA