Seawater carbonate chemistry and photosynthetic potential, cell density, lipid content of Symbiodinium

• Main Authors: Hill, Lilian J, Paradas, Wladimir C, Willemes, Maria Julia, Pereira, Miria G, Salomon, Paulo S, Mariath, Rodrigo, Moura, Rodrigo L, Atella, Georgia C, Farina, Marcos, Amado-Filho, Gilberto M, Salgado, Leonardo T
• Format: Dataset
• Language: English
• Published: PANGAEA 2019
• Subjects: Alkalinity; total; standard deviation; Aragonite saturation state; Bicarbonate ion; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chromista; Coast and continental shelf; Experiment day; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Growth rate; Laboratory experiment; Lipids; Maximum photochemical quantum yield of photosystem II; Myzozoa; Number of cells; Number of pixels; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide; Partial pressure of carbon dioxide (ambient atmosphere); Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; Percentage; pH; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.914234; https://doi.org/10.1594/PANGAEA.914234

Dinoflagellates from the Symbiodiniaceae family and corals have an ecologically important endosymbiotic relationship. Scleractinian corals cannot survive for long periods without their symbionts. These algae, also known as zooxanthellae, on the other hand, thrives outside the coral cells. The free-living populations of zooxanthellae are essential for the resilience of the coral to environmental stressors such as temperature anomalies and ocean acidification. Yet, little is known about how ocean acidification may affect the free-living zooxanthellae. In this study we aimed to test morphological, physiological and biochemical responses of zooxanthellae from the Symbiodinium genus isolated from the coral Mussismilia braziliensis, endemic to the Brazilian coast, to acidification led by increased atmospheric CO2. We tested whether photosynthetic yield, cell ultrastructure, cell density and lipid profile would change after up to 16 days of exposure to pH 7.5 in an atmospheric pCO2 of 1633 μatm. Photosynthetic yield and cell density were negatively affected and chloroplasts showed vesiculated thylakoids, indicating morphological damage. Moreover, Symbiodinium fatty acid profile drastically changed in acidified condition, showing lower polyunsaturated fatty acids and higher saturated fatty acids contents, when compared to the control, non-acidified condition. These results show that seawater acidification as an only stressor causes significant changes in the physiology, biochemistry and ultrastructure of free-living Symbiodinium.