Effects of ocean acidification on the photosynthetic performance, carbonic anhydrase activity and growth of the giant kelp Macrocystis pyrifera, supplement to: Fernández, Pamela A; Roleda, Michael Y; Hurd, Catriona L (2015): Effects of ocean acidification on the photosynthetic performance, carbonic anhydrase activity and growth of the giant kelp Macrocystis pyrifera. Photosynthesis Research, 124(3), 293-304

• Main Authors: Fernández, Pamela A, Roleda, Michael Y, Hurd, Catriona L
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2015
• Subjects: Benthos; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria <20 L; Chromista; Coast and continental shelf; Growth/Morphology; Laboratory experiment; Macroalgae; Macrocystis pyrifera; Ochrophyta; Other metabolic rates; Primary production/Photosynthesis; Single species; South Pacific; Temperate; Species; Figure; Table; Treatment; Inhibition of net photosynthesis; Inhibition of net photosynthesis, standard error; Net photosynthesis rate, oxygen; Net photosynthesis rate, oxygen, standard error; pH; pH, standard error; Change; Change, standard error; Time in days; Carbonic anhydrase activity; Carbonic anhydrase activity, standard error; Growth rate; Growth rate, standard error; Bicarbonate uptake rate; Bicarbonate uptake, standard error; Carbon dioxide uptake rate; Carbon dioxide uptake, standard error; δ15N; δ15N, standard deviation; Nitrogen, total; Nitrogen, standard deviation; δ13C; δ13C, standard deviation; Carbon, total; Carbon, total, standard deviation; Carbon/Nitrogen ratio; Carbon/Nitrogen ratio, standard deviation; Salinity; Temperature, water; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; Bicarbonate ion; Bicarbonate ion, standard deviation; Carbon dioxide; Carbon dioxide, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide, standard deviation; Carbonate system computation flag; Fugacity of carbon dioxide water at sea surface temperature wet air; Aragonite saturation state; Calcite saturation state; Experiment; Spectrophotometric; Coulometric titration; Potentiometric titration; Calculated using SWCO2 Hunter, 2007; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Hurd; Pacific; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.849372; https://doi.pangaea.de/10.1594/PANGAEA.849372

Under ocean acidification (OA), the 200 % increase in CO2(aq) and the reduction of pH by 0.3-0.4 units are predicted to affect the carbon physiology and growth of macroalgae. Here we examined how the physiology of the giant kelp Macrocystis pyrifera is affected by elevated pCO2/low pH. Growth and photosynthetic rates, external and internal carbonic anhydrase (CA) activity, HCO3 (-) versus CO2 use were determined over a 7-day incubation at ambient pCO2 400 µatm/pH 8.00 and a future OA treatment of pCO2 1200 µatm/pH 7.59. Neither the photosynthetic nor growth rates were changed by elevated CO2 supply in the OA treatment. These results were explained by the greater use of HCO3 (-) compared to CO2 as an inorganic carbon (Ci) source to support photosynthesis. Macrocystis is a mixed HCO3 (-) and CO2 user that exhibits two effective mechanisms for HCO3 (-) utilization; as predicted for species that possess carbon-concentrating mechanisms (CCMs), photosynthesis was not substantially affected by elevated pCO2. The internal CA activity was also unaffected by OA, and it remained high and active throughout the experiment; this suggests that HCO3 (-) uptake via an anion exchange protein was not affected by OA. Our results suggest that photosynthetic Ci uptake and growth of Macrocystis will not be affected by elevated pCO2/low pH predicted for the future, but the combined effects with other environmental factors like temperature and nutrient availability could change the physiological response of Macrocystis to OA. Therefore, further studies will be important to elucidate how this species might respond to the global environmental change predicted for the ocean. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2015) 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 is 2015-09-09.