title: Variability of Symbiodinium Communities in Waters, Sediments, and Corals of Thermally Distinct Reef Pools in American Samoa.
abstract: Reef-building corals host assemblages of symbiotic algae (Symbiodinium spp.) whose diversity and abundance may fluctuate under different conditions, potentially facilitating acclimatization to environmental change. The composition of free-living Symbiodinium in reef waters and sediments may also be environmentally labile and may influence symbiotic assemblages by mediating supply and dispersal. The magnitude and spatial scales of environmental influence over Symbiodinium composition in different reef habitat compartments are, however, not well understood. We used pyrosequencing to compare Symbiodinium in sediments, water, and ten coral species between two backreef pools in American Samoa with contrasting thermal environments. We found distinct compartmental assemblages of clades A, C, D, F, and/or G Symbiodinium types, with strong differences between pools in water, sediments, and two coral species. In the pool with higher and more variable temperatures, abundance of various clade A and C types differed compared to the other pool, while abundance of D types was lower in sediments but higher in water and in Pavona venosa, revealing an altered habitat distribution and potential linkages among compartments. The lack of between-pool effects in other coral species was due to either low overall variability (in the case of Porites) or high within-pool variability. Symbiodinium communities in water and sediment also showed within-pool structure, indicating that environmental influences may operate over multiple, small spatial scales. This work suggests that Symbiodinium composition is highly labile in reef waters, sediments, and some corals, but the underlying drivers and functional consequences of this plasticity require further testing with high spatial resolution biological and environmental sampling.
authors.affiliation: University of Hawai'i, Hawai'i Institute of Marine Biology, PO Box 1346, Kāne'ohe, Hawaii, 96744, United States of America.
authors.forename: Ross
authors.initials: R
authors.lastname: Cunning
authors.affiliation: University of Hawai'i, Hawai'i Institute of Marine Biology, PO Box 1346, Kāne'ohe, Hawaii, 96744, United States of America.
authors.forename: Denise M
authors.initials: DM
authors.lastname: Yost
authors.affiliation: Northwest Knowledge Network, University of Idaho, 875 Perimeter Dr. MS2358, Moscow, Idaho, 83844, United States of America.
authors.forename: Marisa L
authors.initials: ML
authors.lastname: Guarinello
authors.affiliation: University of Hawai'i, Hawai'i Institute of Marine Biology, PO Box 1346, Kāne'ohe, Hawaii, 96744, United States of America.
authors.forename: Hollie M
authors.initials: HM
authors.lastname: Putnam
authors.affiliation: University of Hawai'i, Hawai'i Institute of Marine Biology, PO Box 1346, Kāne'ohe, Hawaii, 96744, United States of America.
authors.forename: Ruth D
authors.initials: RD
authors.lastname: Gates
mesh_terms: D018948:American Samoa; D000818:Animals; D037421:Anthozoa / Q000382:microbiology*; D044822:Biodiversity; D019295:Computational Biology; D057894:Coral Reefs; D004141:Dinoflagellida / Q000145:classification* / Q000235:genetics; D019015:Geologic Sediments / Q000382:microbiology*; D059014:High-Throughput Nucleotide Sequencing; D012623:Seawater / Q000382:microbiology*; D013696:Temperature