The responses of eight coral reef calcifiers to increasing partial pressure of CO2 do not exhibit a tipping point, supplement to: Comeau, Steeve; Edmunds, Peter J; Spindel, N B; Carpenter, Robert C (2013): The responses of eight coral reef calcifiers to increasing partial pressure of CO2 do not exhibit a tipping point. Limnology and Oceanography, 58(1), 388-398

• Main Authors: Comeau, Steeve, Edmunds, Peter J, Spindel, N B, Carpenter, Robert C
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2013
• Subjects: Acropora pulchra; Animalia; Benthic animals; Benthos; Calcification/Dissolution; Chlorophyta; Cnidaria; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Halimeda macroloba; Halimeda minima; Hydrolithon reinboldii; Laboratory experiment; Lithophyllum flavescens; Macroalgae; Pavona cactus; Plantae; Pocillopora damicornis; Porites rus; Rhodophyta; Single species; South Pacific; Tropical; Species; Partial pressure of carbon dioxide water at sea surface temperature wet air; Alkalinity, total; pH; Temperature, water; Salinity; Calcification rate of calcium carbonate; Date/time start; Date/time end; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Carbon, inorganic, dissolved; Aragonite saturation state; Calcite saturation state; Potentiometric titration; Potentiometric; Buoyant weighing technique Davies, 1989; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Pacific; Rus’; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.833687; https://doi.pangaea.de/10.1594/PANGAEA.833687

The objective of this study was to investigate whether a tipping point exists in the calcification responses of coral reef calcifiers to CO2. We compared the effects of six partial pressures of CO2 (PCO2) from 28 Pa to 210 Pa on the net calcification of four corals (Acropora pulchra, Porites rus, Pocillopora damicornis, and Pavona cactus), and four calcified algae (Hydrolithon onkodes, Lithophyllum flavescens, Halimeda macroloba, and Halimeda minima). After 2 weeks of acclimation in a common environment, organisms were incubated in 12 aquaria for 2 weeks at the targeted PCO2 levels and net calcification was quantified. All eight species calcified at the highest PCO2 in which the calcium carbonate aragonite saturation state was ~1. Calcification decreased linearly as a function of increasing partial PCO2 in three corals and three algae. Overall, the decrease in net calcification as a function of decreasing pH was ~10% when ambient PCO2 (39 Pa) was doubled. The calcification responses of P. damicornis and H. macroloba were unaffected by increasing PCO2. These results are inconsistent with the notion that coral reefs will be affected by rising PCO2 in a response characterized by a tipping point. Instead, our findings combined among taxa suggest a gradual decline in calcification will occur, but this general response includes specific cases of complete resistance to rising PCO2. Together our results suggest that the overall response of coral reef communities to ocean acidification will be monotonic and inversely proportional to PCO2, with reef-wide responses dependent on the species composition of calcifying taxa. : 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 2014-05-16.