Format

Send to

Choose Destination
Biol Open. 2017 Dec 15;6(12):1943-1948. doi: 10.1242/bio.028878.

High salinity conveys thermotolerance in the coral model Aiptasia.

Author information

1
Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
2
Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia christian.voolstra@kaust.edu.sa.

Abstract

The endosymbiosis between dinoflagellate algae of the genus Symbiodinium and stony corals provides the foundation of coral reef ecosystems. Coral bleaching, the expulsion of endosymbionts from the coral host tissue as a consequence of heat or light stress, poses a threat to reef ecosystem functioning on a global scale. Hence, a better understanding of the factors contributing to heat stress susceptibility and tolerance is needed. In this regard, some of the most thermotolerant corals live in particularly saline habitats, but possible effects of high salinity on thermotolerance in corals are anecdotal. Here we test the hypothesis that high salinity may lead to increased thermotolerance. We conducted a heat stress experiment at low, intermediate, and high salinities using a set of host-endosymbiont combinations of the coral model Aiptasia. As expected, all host-endosymbiont combinations showed reduced photosynthetic efficiency and endosymbiont loss during heat stress, but the severity of bleaching was significantly reduced with increasing salinities for one of the host-endosymbiont combinations. Our results show that higher salinities can convey increased thermotolerance in Aiptasia, although this effect seems to be dependent on the particular host strain and/or associated symbiont type. This finding may help explain the extraordinarily high thermotolerance of corals in high salinity environments, such as the Red Sea and the Persian/Arabian Gulf, and provides novel insight regarding factors that contribute to thermotolerance. Since our results are based on a salinity effect in symbiotic sea anemones, it remains to be determined whether this salinity effect can also be observed in stony corals.

KEYWORDS:

Bleaching; Climate change; Coral reefs; Heat stress; Resilience; Symbiodinium; Symbiosis; Thermotolerance

Conflict of interest statement

Competing interestsThe authors declare no competing or financial interests.

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center