Seawater carbonate chemistry and biological processed during experiments with corals Porites sp. & Stylophora pistillata, 2010, supplement to: Krief, Shani; Hendy, Erica J; Fine, M; Yam, Ruth; Meibom, Anders; Foster, Gavin L; Shemesh, Aldo (2010): Physiological and isotopic responses of scleractinian corals to ocean acidification. Geochimica et Cosmochimica Acta, 74, 4988–5001

• Main Authors: Krief, Shani, Hendy, Erica J, Fine, M, Yam, Ruth, Meibom, Anders, Foster, Gavin L, Shemesh, Aldo
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2010
• Subjects: Animalia; Benthic animals; Benthos; Biomass/Abundance/Elemental composition; Calcification/Dissolution; Cnidaria; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Growth/Morphology; Laboratory experiment; Porites sp.; Red Sea; Single species; Stylophora pistillata; Temperate; Experimental treatment; Species; Salinity; Temperature, water; LightDark cycle; Radiation, photosynthetically active; pH; Carbon, inorganic, dissolved; Aragonite saturation state; Alkalinity, total; Carbonate system computation flag; Carbon dioxide; Partial pressure of carbon dioxide water at sea surface temperature wet air; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Calcite saturation state; δ13C, dissolved inorganic carbon; δ18O, water; δ13C, standard deviation; δ18O, standard deviation; δ11B; δ11B, standard deviation; Protein per surface area; Protein per surface area, standard deviation; Zooxanthellae per surface area; Zooxanthellae per surface area, standard deviation; Zooxanthellae, per protein content; Zooxanthellae per protein content, standard deviation; Chlorophyll per zooxanthellae; Chlorophyll per zooxanthellae, standard deviation; Growth rate; Growth rate, standard deviation; Calcification rate; Calcification rate, standard deviation; HOBO Pendant Temp/Light Data Loggers Pocasset, MA, USA; Measured; pH, Electrode; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. 2010; Element analyser isotope ratio mass spectrometer EA-IRMS; Continuous Flow Isotope Ratio Mass Spectrometry CF/IRMS; MC-ICP-MS Thermo-Finnigan Neptune; Image analysis; 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; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.754785; https://doi.pangaea.de/10.1594/PANGAEA.754785

Uptake of anthropogenic CO2 by the oceans is altering seawater chemistry with potentially serious consequences for coral reef ecosystems due to the reduction of seawater pH and aragonite saturation state (omega arag). The objectives of this long-term study were to investigate the viability of two ecologically important reef-building coral species, massive Porites sp. and Stylophora pistilata, exposed to high pCO2(or low pH) conditions and to observe possible changes in physiologically related parameters as well as skeletal isotopic composition. Fragments of Porites sp. and S. pistilata were kept for 6-14 months under controlled aquarium conditions characterized by normal and elevated pCO2 conditions, corresponding to pHTvalues of 8.09, 7.49, and 7.19, respectively. In contrast with shorter, and therefore more transient experiments, the long experimental timescale achieved in this study ensures complete equilibration and steady state with the experimental environment and guarantees that the data provide insights into viable and stably growing corals. During the experiments, all coral fragments survived and added new skeleton, even at seawater omega arag <1, implying that the coral skeleton is formed by mechanisms under strong biological control. Measurements of boron (B), carbon (C) and oxygen (O) isotopic composition of skeleton, C isotopic composition of coral tissue and symbiont zooxanthellae, along with physiological data (such as skeletal growth, tissue biomass, zooxanthellae cell density and chlorophyll concentration) allow for a direct comparison with corals living under normal conditions and sampled simultaneously. Skeletal growth and zooxanthellae density were found to decrease, whereas coral tissue biomass (measured as protein concentration) and zooxanthellae chlorophyll concentrations increased under high pCO2 (low pH) conditions. Both species showed similar trends of delta11B depletion and delta18O enrichment under reduced pH, whereas the delta13C results imply species-specific metabolic response to high pCO2 conditions. The skeletal delta11B values plot above seawater delta11B vs. pH borate fractionation curves calculated using either the theoretically derived deltaB value of 1.0194 (Kakihana et al., Bull. Chem. Soc. Jpn. 50(1977), 158) or the empirical deltaB value of 1.0272 (Klochko et al., EPSL 248 (2006), 261). However, the effective deltaB must be greater than 1.0200 in order to yield calculated coral skeletal delta11B values for pH conditions where omega arag >1. The delta11B vs. pH offset from the literature seawater delta11B vs. pH fractionation curves suggests a change in the ratio of skeletal material laid down during dark and light calcification and/or an internal pH regulation, presumably controlled by ion-transport enzymes. Finally, seawater pH significantly influences skeletal delta13C and delta18O. This must be taken into consideration when reconstructing paleo-environmental conditions from coral skeleton : 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).