M. Ziegler, C. Arif, J.A. Burt, S. Dobretsov, C. Roder, T.C. Lajeunesse, C.R. Voolstra
Journal of Biogeography, 136, (2017)
Coral reefs rely on the symbiosis between scleractinian corals and intracellular, photosynthetic dinoflagellates of the genus Symbiodinium
making the assessment of symbiont diversity critical to our
understanding of ecological resilience of these ecosystems. This study
characterizes Symbiodinium diversity around the Arabian Peninsula, which contains some of the most thermally diverse and understudied reefs on Earth.
Shallow water coral reefs throughout the Red Sea (RS), Sea of Oman (SO), and Persian/Arabian Gulf (PAG).
Next-generation sequencing of the ITS2 marker gene was used to assess Symbiodinium community composition and diversity comprising 892 samples from 46 hard and soft coral genera.
Corals were associated with a large diversity of Symbiodinium, which usually consisted of one or two prevalent symbiont types and many types at low abundance. Symbiodinium
communities were strongly structured according to geographical region
and to a lesser extent by coral host identity. Overall symbiont
communities were composed primarily of species from clade A and C in the
RS, clade A, C, and D in the SO, and clade C and D in the PAG,
representing a gradual shift from C- to D-dominated coral hosts. The
analysis of symbiont diversity in an Operational Taxonomic Unit
(OTU)-based framework allowed the identification of differences in
symbiont taxon richness over geographical regions and host genera.
Our study represents a comprehensive overview over biogeography and molecular diversity of Symbiodinium
in the Arabian Seas, where coral reefs thrive in one of the most
extreme environmental settings on the planet. As such our data will
serve as a baseline for further exploration into the effects of
environmental change on host–symbiont pairings and the identification
and ecological significance of Symbiodinium types from regions already experiencing ‘Future Ocean’ conditions.