CO2-driven seawater acidification increases photochemical stress in a green alga

• Main Authors: Liu, Yuting, Xu, Juntian, Gao, Kunshan
• Format: Dataset
• Language: English
• Published: PANGAEA 2012
• Subjects: Alkalinity; total; Aragonite saturation state; Benthos; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; standard deviation; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chlorophyta; Coast and continental shelf; Effective quantum yield; Electron transport rate; relative; EXP; Experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Identification; Irradiance; Laboratory experiment; Lianyungang_OA; Macroalgae; Non photochemical quenching; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Plantae; Potentiometric; Primary production/Photosynthesis; Salinity; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.830590; https://doi.org/10.1594/PANGAEA.830590

Increased CO2 and associated acidification in seawater, known as ocean acidification, decreases calcification of most marine calcifying organisms. However, there is little information available on how marine macroalgae would respond to the chemical changes caused by seawater acidification. We hypothesized that down-regulation of bicarbonate acquisition by algae under increased acidity and CO2 levels would lower the threshold above which photosynthetically active radiation (PAR) becomes excessive. Juveniles of Ulva prolifera derived from zoospores were grown at ambient (390 µatm) and elevated (1000 µatm) CO2 concentrations for 80 days before the hypothesis was tested. Here, the CO2-induced seawater acidification increased the quantum yield under low levels of light, but induced higher nonphotochemical quenching under high light. At the same time, the PAR level at which photosynthesis became saturated was decreased and the photosynthetic affinity for CO2 or inorganic carbon decreased in the high-CO2 grown plants. These findings indicated that ocean acidification, as an environmental stressor, can reduce the threshold above which PAR becomes excessive.