Diurnal fluctuations in seawater pH influence the response of a calcifying macroalga to ocean acidification, supplement to: Cornwall, Christopher Edward; Hepburn, Christopher D; McGraw, Christina M; Currie, Kim I; Pilditch, Conrad A; Hunter, Keith A; Boyd, Philip W; Hurd, Catriona L (2013): Diurnal fluctuations in seawater pH influence the response of a calcifying macroalga to ocean acidification. Proceedings of the Royal Society B-Biological Sciences, 280(1772), 20132201-20132201

• Main Authors: Cornwall, Christopher Edward, Hepburn, Christopher D, McGraw, Christina M, Currie, Kim I, Pilditch, Conrad A, Hunter, Keith A, Boyd, Philip W, Hurd, Catriona L
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2013
• Subjects: Arthrocardia corymbosa; Benthos; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria <20 L; Coast and continental shelf; Growth/Morphology; Laboratory experiment; Macroalgae; Plantae; Primary production/Photosynthesis; Reproduction; FOS Medical biotechnology; Rhodophyta; Single species; South Pacific; Temperate; Species; Treatment; Incubation duration; Gross photosynthesis rate, oxygen; Gross photosynthesis rate, oxygen, standard error; Growth rate; Growth rate, standard error; Recruitment; Recruitment, standard error; Maximum photochemical quantum yield of photosystem II; Maximum photochemical quantum yield of photosystem II, standard error; Calcium; Calcium, standard error; Magnesium; Magnesium, standard error; Magnesium carbonate, magnesite; Magnesium carbonate, magnesite, standard error; δ13C, inorganic carbon; δ13C, inorganic carbon, standard error; Chlorophyll a; Chlorophyll a, standard error; Phycocyanin; Phycocyanin, standard error; Phycoerythrin; Phycoerythrin, standard error; Carbon/Nitrogen ratio; Carbon/Nitrogen ratio, standard error; δ13C, organic carbon; δ13C, organic carbon, standard error; δ15N, organic matter; δ15N, organic matter, standard error; Temperature, water; Salinity; pH; pH, standard error; Alkalinity, total; Alkalinity, total, standard error; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard error; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide water at sea surface temperature wet air, standard error; Carbonate ion; Carbonate ion, standard error; Bicarbonate ion; Bicarbonate ion, standard error; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Aragonite saturation state; Calcite saturation state; Experiment; Potentiometric; Potentiometric titration; Calculated; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Pacific; Cornwall; Hurd; Currie; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.833265; https://doi.pangaea.de/10.1594/PANGAEA.833265

Coastal ecosystems that are characterized by kelp forests encounter daily pH fluctuations, driven by photosynthesis and respiration, which are larger than pH changes owing to ocean acidification (OA) projected for surface ocean waters by 2100. We investigated whether mimicry of biologically mediated diurnal shifts in pH-based for the first time on pH time-series measurements within a kelp forest-would offset or amplify the negative effects of OA on calcifiers. In a 40-day laboratory experiment, the calcifying coralline macroalga, Arthrocardia corymbosa, was exposed to two mean pH treatments (8.05 or 7.65). For each mean, two experimental pH manipulations were applied. In one treatment, pH was held constant. In the second treatment, pH was manipulated around the mean (as a step-function), 0.4 pH units higher during daylight and 0.4 units lower during darkness to approximate diurnal fluctuations in a kelp forest. In all cases, growth rates were lower at a reduced mean pH, and fluctuations in pH acted additively to further reduce growth. Photosynthesis, recruitment and elemental composition did not change with pH, but ?(13)C increased at lower mean pH. Including environmental heterogeneity in experimental design will assist with a more accurate assessment of the responses of calcifiers to OA. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne et al, 2014) 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 2014-06-10.