Seawater carbonate chemistry and processes during experiments with a coral community, 2008, supplement to: Anthony, Kenneth R N; Kline, David I; Diaz-Pulido, Guillermo; Dove, Sophie; Hoegh-Guldberg, Ove (2008): Ocean acidification causes bleaching and productivity loss in coral reef builders. Proceedings of the National Academy of Sciences of the United States of America, 105(45), 7442-7446

• Main Authors: Anthony, Kenneth R N, Kline, David I, Diaz-Pulido, Guillermo, Dove, Sophie, Hoegh-Guldberg, Ove
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2008
• Subjects: Acropora intermedia; Animalia; Benthic animals; Benthos; Calcification/Dissolution; Cnidaria; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Laboratory experiment; Macroalgae; Other studied parameter or process; Plantae; Porites lobata; Porolithon onkodes; Primary production/Photosynthesis; Rhodophyta; Single species; South Pacific; Temperate; Temperature; Salinity; Temperature, water; Carbonate system computation flag; pH; Alkalinity, total; Carbon, inorganic, dissolved; Partial pressure of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Aragonite saturation state; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Calcite saturation state; Bleaching; Net productivity of oxygen; Calcification rate; Experiment; Refractometer, Bellingham Stanley; Calculated using seacarb after Nisumaa et al. 2010; pH logger, MicroChem interface TPS Australia; Alkalinity, Gran titration Gran, 1950; Calculated using CO2SYS; Calculated, see references; Buoyant weighing technique Davies, 1989; European network of excellence for Ocean Ecosystems Analysis EUR-OCEANS; European Project on Ocean Acidification EPOCA; Ocean Acidification International Coordination Centre OA-ICC; Diaz; Hoegh; Pacific; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.727744; https://doi.pangaea.de/10.1594/PANGAEA.727744

Ocean acidification represents a key threat to coral reefs by reducing the calcification rate of framework builders. In addition, acidification is likely to affect the relationship between corals and their symbiotic dinoflagellates and the productivity of this association. However, little is known about how acidification impacts on the physiology of reef builders and how acidification interacts with warming. Here, we report on an 8-week study that compared bleaching, productivity, and calcification responses of crustose coralline algae (CCA) and branching (Acropora) and massive (Porites) coral species in response to acidification and warming. Using a 30-tank experimental system, we manipulated CO2 levels to simulate doubling and three- to fourfold increases [Intergovernmental Panel on Climate Change (IPCC) projection categories IV and VI] relative to present-day levels under cool and warm scenarios. Results indicated that high CO2 is a bleaching agent for corals and CCA under high irradiance, acting synergistically with warming to lower thermal bleaching thresholds. We propose that CO2 induces bleaching via its impact on photoprotective mechanisms of the photosystems. Overall, acidification impacted more strongly on bleaching and productivity than on calcification. Interestingly, the intermediate, warm CO2 scenario led to a 30% increase in productivity in Acropora, whereas high CO2 lead to zero productivity in both corals. CCA were most sensitive to acidification, with high CO2 leading to negative productivity and high rates of net dissolution. Our findings suggest that sensitive reef-building species such as CCA may be pushed beyond their thresholds for growth and survival within the next few decades whereas corals will show delayed and mixed responses. : 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).