Journal article
Corals in the hottest reefs in the world exhibit symbiont fidelity not flexibility
Molecular ecology, Vol.29(5), pp.899-911
10/03/2020
PMID: 32017263
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Source: InCites
Abstract
Reef-building corals are at risk of extinction from ocean warming. While some corals can enhance their thermal limits by associating with dinoflagellate photosymbionts of superior stress tolerance, the extent to which symbiont communities will reorganize under increased warming pressure remains unclear. Here we show that corals in the hottest reefs in the world in the Persian Gulf maintain associations with the same symbionts across 1.5 years despite extreme seasonal warming and acute heat stress (≥35°C). Persian Gulf corals predominantly associated with Cladocopium (clade C) and most also hosted Symbiodinium (clade A) and/or Durusdinium (clade D). This is in contrast to the neighbouring and milder Oman Sea, where corals associated with Durusdinium and only a minority hosted background levels of Cladocopium. During acute heat stress, the higher prevalence of Symbiodinium and Durusdinium in bleached versus nonbleached Persian Gulf corals indicates that genotypes of these background genera did not confer bleaching resistance. Within symbiont genera, the majority of ITS2 rDNA type profiles were unique to their respective coral species, confirming the existence of host-specific symbiont lineages. Notably, further differentiation among Persian Gulf sites demonstrates that symbiont populations are either isolated or specialized over tens to hundreds of kilometres. Thermal tolerance across coral species was associated with the prevalence of a single ITS2 intragenomic sequence variant (C3gulf), definitive of the Cladocopium thermophilum group. The abundance of C3gulf was highest in bleaching-resistant corals and at warmer sites, potentially indicating a specific symbiont genotype (or set of genotypes) that may play a role in thermal tolerance that warrants further investigation. Together, our findings indicate that co-evolution of host-Symbiodiniaceae partnerships favours fidelity rather than flexibility in extreme environments and under future warming.
Details
- Title
- Corals in the hottest reefs in the world exhibit symbiont fidelity not flexibility
- Creators
- Emily J Howells - Centre for Sustainable Ecosystem Solutions and School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, AustraliaAndrew G Bauman - Experimental Marine Ecology Laboratory, Department of Biological Sciences, National University of Singapore, Singapore City, SingaporeGrace O Vaughan - Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab EmiratesBenjamin C C Hume - Red Sea Research Center, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi ArabiaChristian R Voolstra - Department of Biology, University of Konstanz, Konstanz, GermanyJohn A Burt - Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- Publication Details
- Molecular ecology, Vol.29(5), pp.899-911
- Publisher
- Wiley-Blackwell Publishing Ltd.
- Grant note
- The work was funded by New York University Abu Dhabi (J.A.B.) and King Abdullah University of Science and Technology (C.R.V.).
- Identifiers
- 991012966700402368
- Academic Unit
- Faculty of Science and Engineering; National Marine Science Centre
- Language
- English
- Resource Type
- Journal article