title: Biogeography and molecular diversity of coral symbionts in the genusSymbiodiniumaround the Arabian Peninsula.
abstract: Coral reefs rely on the symbiosis between scleractinian corals and intracellular, photosynthetic dinoflagellates of the genusSymbiodiniummaking the assessment of symbiont diversity critical to our understanding of ecological resilience of these ecosystems. This study characterizesSymbiodiniumdiversity 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 assessSymbiodiniumcommunity composition and diversity comprising 892 samples from 46 hard and soft coral genera.
  
  
  
  Corals were associated with a large diversity ofSymbiodinium, which usually consisted of one or two prevalent symbiont types and many types at low abundance.Symbiodiniumcommunities 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 ofSymbiodiniumin 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 ofSymbiodiniumtypes from regions already experiencing 'Future Ocean' conditions.
authors.affiliation: Division of Biological and Environmental Science and Engineering (BESE) Red Sea Research Center King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia.
authors.forename: Maren
authors.initials: M
authors.lastname: Ziegler
authors.affiliation: Division of Biological and Environmental Science and Engineering (BESE) Red Sea Research Center King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia.
authors.forename: Chatchanit
authors.initials: C
authors.lastname: Arif
authors.affiliation: Center for Genomics and Systems Biology New York University Abu Dhabi Abu Dhabi United Arab Emirates.
authors.forename: John A
authors.initials: JA
authors.lastname: Burt
authors.affiliation: Department of Marine Science and Fisheries College of Agricultural and Marine Sciences Sultan Qaboos University Muscat Oman.
authors.forename: Sergey
authors.initials: S
authors.lastname: Dobretsov
authors.affiliation: Division of Biological and Environmental Science and Engineering (BESE) Red Sea Research Center King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia; Shelf Sea System Ecology Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Roder
authors.affiliation: Department of Biology Pennsylvania State University University Park PA 16802 USA.
authors.forename: Todd C
authors.initials: TC
authors.lastname: LaJeunesse
authors.affiliation: Division of Biological and Environmental Science and Engineering (BESE) Red Sea Research Center King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia.
authors.forename: Christian R
authors.identifier: 0000-0003-4555-3795
authors.initials: CR
authors.lastname: Voolstra
keywords: ITS2; Persian/Arabian Gulf; Red Sea; Sea of Oman; coral reef; ecosystem; next‐generation sequencing; symbiosis