title: Effects of reduced salinity on the photosynthetic characteristics and intracellular DMSP concentrations of the red coralline alga,Lithothamnion glaciale.
abstract: Mid- to high-latitude fjordic coastal environments experience naturally variable salinity regimes. Climate projections suggest that freshwater input into the coastal ocean will increase in the future, exposing coastal organisms to further periods of reduced salinity. This study investigated the effect of low salinity onLithothamnion glaciale, a red coralline alga found in mid- to high-latitude fjordic regions, during a 21-day experiment. Specific measurements included: the intracellular concentration of dimethylsulphoniopropionate (DMSP, an algal secondary metabolite and major precursor to the climatically active gas dimethylsulphide), pigment composition and photosynthetic characteristics. No significant difference in intracellular DMSP concentrations was observed between treatments, suggesting that the primary function for DMSP inL. glacialeis not as a compatible solute, perhaps favouring an antioxidant role . Photosynthetic parameters (including pigment composition) exhibited a mixed response, suggesting some degree of photosynthetic resilience to reduced salinity. This study provides evidence of intracellular mechanisms adopted byL. glacialein response to reduced salinity. This has significant implications for the survival ofL. glacialeunder a projected freshening scenario and provides organism-level detail to ecosystem-level projected changes should lower-salinity conditions become more frequent and more intense in the future.
authors.affiliation: Scottish Oceans Institute, University of St Andrews, St Andrews, UK ; Department of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK ; School of Geographical and Earth Sciences, University of Glasgow, Glasgow, UK.
authors.forename: Heidi L
authors.initials: HL
authors.lastname: Burdett
authors.affiliation: Scottish Association for Marine Science, Oban, UK.
authors.forename: Angela D
authors.initials: AD
authors.lastname: Hatton
authors.affiliation: School of Geographical and Earth Sciences, University of Glasgow, Glasgow, UK.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Kamenos