Symbiotic plasticity of Symbiodinium in a common excavating sponge

Fang, James K. H., Schonberg, Christine H. L. , Hoegh-Guldberg, Ove and Dove, Sophie (2017) Symbiotic plasticity of Symbiodinium in a common excavating sponge. Marine Biology, 164 5: . doi:10.1007/s00227-017-3088-y


Author Fang, James K. H.
Schonberg, Christine H. L. 
Hoegh-Guldberg, Ove
Dove, Sophie
Title Symbiotic plasticity of Symbiodinium in a common excavating sponge
Formatted title
Symbiotic plasticity of Symbiodinium in a common excavating sponge
Journal name Marine Biology   Check publisher's open access policy
ISSN 0025-3162
1432-1793
Publication date 2017-05-01
Sub-type Article (original research)
DOI 10.1007/s00227-017-3088-y
Open Access Status Not yet assessed
Volume 164
Issue 5
Total pages 11
Place of publication Heidelberg, Germany
Publisher Springer
Language eng
Subject 1105 Ecology, Evolution, Behavior and Systematics
1104 Aquatic Science
2303 Ecology
Abstract Dinoflagellates of the genus Symbiodinium are symbiotic with a wide range of marine invertebrates. Broadly described as a mutualistic symbiosis, possible parasitic tendencies of Symbiodinium are less well known. The present study investigated the potential for mutualistic Symbiodinium to become parasitic in the excavating sponge Cliona orientalis, a ubiquitous bioeroder on Indo-Pacific coral reefs. We report the surprising observation that the growth, asexual reproduction and population density of Symbiodinium in C. orientalis were apparently unaffected when photosynthesis was reduced to zero in complete darkness for 20 days. Symbiodinium remained functional in hospite following the dark treatment, although with reduced photosynthetic efficiency compared to the control treatment under a daily light cycle. Rates of dark respiration and net uptake of heterotrophic carbon by the holobiont were similar between the control and dark treatments. However, dark-treated C. orientalis displayed a negative carbon budget that indicated compromised host growth, along with reduced biomass and bioerosion capability. Our findings suggest that, when lacking photo-autotrophic energy, Symbiodinium possibly sustains itself through heterotrophy at the expense of its hosts. This transfer of host materials to the symbiont suggests parasitism that may be associated with the observed deterioration of C. orientalis in the dark treatment. Overall, our study implies plasticity of Symbiodinium in terms of shifting its symbiotic role between mutualism and parasitism.
Formatted abstract
Dinoflagellates of the genus Symbiodinium are symbiotic with a wide range of marine invertebrates. Broadly described as a mutualistic symbiosis, possible parasitic tendencies of Symbiodinium are less well known. The present study investigated the potential for mutualistic Symbiodinium to become parasitic in the excavating sponge Cliona orientalis, a ubiquitous bioeroder on Indo-Pacific coral reefs. We report the surprising observation that the growth, asexual reproduction and population density of Symbiodinium in C. orientalis were apparently unaffected when photosynthesis was reduced to zero in complete darkness for 20 days. Symbiodinium remained functional in hospite following the dark treatment, although with reduced photosynthetic efficiency compared to the control treatment under a daily light cycle. Rates of dark respiration and net uptake of heterotrophic carbon by the holobiont were similar between the control and dark treatments. However, dark-treated C. orientalis displayed a negative carbon budget that indicated compromised host growth, along with reduced biomass and bioerosion capability. Our findings suggest that, when lacking photo-autotrophic energy, Symbiodinium possibly sustains itself through heterotrophy at the expense of its hosts. This transfer of host materials to the symbiont suggests parasitism that may be associated with the observed deterioration of C. orientalis in the dark treatment. Overall, our study implies plasticity of Symbiodinium in terms of shifting its symbiotic role between mutualism and parasitism.
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID CE0561435
LP0775303
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
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