Experiment: Elevated CO2 levels affect the activity of nitrate reductase and carbonic anhydrase in the calcifying rhodophyte Corallina officinalis, supplement to: Hofmann, Laurie C; Straub, Susanne M; Bischof, Kai (2013): Elevated CO2 levels affect the activity of nitrate reductase and carbonic anhydrase in the calcifying rhodophyte Corallina officinalis. Journal of Experimental Botany, 64(4), 899-908

• Main Authors: Hofmann, Laurie C, Straub, Susanne M, Bischof, Kai
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2013
• Subjects: Benthos; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Corallina officinalis; Laboratory experiment; Macroalgae; North Atlantic; Other metabolic rates; Plantae; Rhodophyta; Single species; Temperate; Species; Identification; Treatment; Phosphate uptake rate; Nitrate uptake rate; Ammonium uptake rate; Date; Group; Carbonic anhydrase, activity; Carbon, inorganic, total; Nitrate reductase activity; Salinity; Temperature, water; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide, standard deviation; pH; pH, standard deviation; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Carbon, inorganic, dissolved; Alkalinity, total; Aragonite saturation state; Calcite saturation state; Calculated using seacarb after Nisumaa et al. 2010; Biological Impacts of Ocean Acidification BIOACID; Ocean Acidification International Coordination Centre OA-ICC; Hofmann; Laurie; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.830299; https://doi.pangaea.de/10.1594/PANGAEA.830299

The concentration of CO2 in global surface ocean waters is increasing due to rising atmospheric CO2 emissions, resulting in lower pH and a lower saturation state of carbonate ions. Such changes in seawater chemistry are expected to impact calcification in calcifying marine organisms. However, other physiological processes related to calcification might also be affected, including enzyme activity. In a mesocosm experiment, macroalgal communities were exposed to three CO2 concentrations (380, 665, and 1486 µatm) to determine how the activity of two enzymes related to inorganic carbon uptake and nutrient assimilation in Corallina officinalis, an abundant calcifying rhodophyte, will be affected by elevated CO2 concentrations. The activity of external carbonic anhydrase, an important enzyme functioning in macroalgal carbon-concentrating mechanisms, was inversely related to CO2 concentration after long-term exposure (12 weeks). Nitrate reductase, the enzyme responsible for reduction of nitrate to nitrite, was stimulated by CO2 and was highest in algae grown at 665 µatm CO2. Nitrate and phosphate uptake rates were inversely related to CO2, while ammonium uptake was unaffected, and the percentage of inorganic carbon in the algal skeleton decreased with increasing CO2. The results indicate that the processes of inorganic carbon and nutrient uptake and assimilation are affected by elevated CO2 due to changes in enzyme activity, which change the energy balance and physiological status of C. officinalis, therefore affecting its competitive interactions with other macroalgae. The ecological implications of the physiological changes in C. officinalis in response to elevated CO2 are discussed. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne and Gattuso, 2011) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2014-02-11.