Effects of temperature on dimethylsulfoniopropionate concentration in Symbiodinium (Freudenthal 1962)

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Miller, Juliana Rose
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Coral reefs are ecologically and economically important in many locations throughout the tropical oceans. However, corals are sensitive to various environmental stressors such as increases in sea surface temperature (SST). Dimethylsulfoniopropionate (DMSP) and related biogenic sulfur compounds are believed to be involved in alleviating intracellular oxidative stress and on a larger scale can function as part of a negative feedback loop to global warming. It has been hypothesized that the breakdown of DMSP into the volatile compound DMS can combat intracellular oxidative stress by scavenging free radicals in cells. The majority of research on DMSP has focused on pelagic phytoplankton; however, more recently there has been an increase in the study of DMSP production in coral reefs. This study measured change in DMSP and glutathione (GSH) in the coral symbiotic algae, Symbiodinium spp.. Holobiont experiments using the coral Anthelia sp., did not show an increase in DMSP concentration with increased temperature. However, Symbiodinium spp. culture experiments using two different unialgal strains showed that increased temperatures led to increased levels of DMSP and the known antioxidant glutathione (GSH). The results from this investigation supports the hypothesis that DMSP functions as an antioxidant and that heat stress increased the cellular quota of DMSP and GSH. Negative results seen in the holobiont experiment may be due to different antioxidant defenses, eurythermal properties of Anthelia, or high DMSP turnover.
Marine biology; Biogeochemistry; Coral reef ecology