Impact of high CO2 on the geochemistry of the coralline algae Lithothamnion glaciale, supplement to: Ragazzola, Federica; Foster, Laura C; Jones, C J; Scott, T B; Fietzke, Jan; Kilburn, M R; Schmidt, Daniela N (2016): Impact of high CO2 on the geochemistry of the coralline algae Lithothamnion glaciale. Scientific Reports, 6, 20572

• Main Authors: Ragazzola, Federica, Foster, Laura C, Jones, C J, Scott, T B, Fietzke, Jan, Kilburn, M R, Schmidt, Daniela N
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2016
• Subjects: Benthos; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria <20 L; Coast and continental shelf; Laboratory experiment; Lithothamnion glaciale; Macroalgae; North Atlantic; Plantae; Rhodophyta; Single species; Temperate; Type; Species; Registration number of species; Uniform resource locator/link to reference; Sample ID; Location; Magnesium/Calcium ratio; Magnesium/Calcium ratio, standard error; Strontium/Calcium ratio; Strontium/Calcium ratio, standard error; pH; pH, standard deviation; Salinity; Salinity, standard deviation; Temperature, water; Temperature, water, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Carbon, inorganic, dissolved; Aragonite saturation state; Calcite saturation state; Experiment; Potentiometric titration; Calculated using seacarb after Nisumaa et al. 2010; Biological Impacts of Ocean Acidification BIOACID; Ocean Acidification International Coordination Centre OA-ICC; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.867382; https://doi.pangaea.de/10.1594/PANGAEA.867382

Coralline algae are a significant component of the benthic ecosystem. Their ability to withstand physical stresses in high energy environments relies on their skeletal structure which is composed of high Mg-calcite. High Mg-calcite is, however, the most soluble form of calcium carbonate and therefore potentially vulnerable to the change in carbonate chemistry resulting from the absorption of anthropogenic CO2 by the ocean. We examine the geochemistry of the cold water coralline alga Lithothamnion glaciale grown under predicted future (year 2050) high pCO2 (589 matm) using Electron microprobe and NanoSIMS analysis. In the natural and control material, higher Mg calcite forms clear concentric bands around the algal cells. As expected, summer growth has a higher Mg content compared to the winter growth. In contrast, under elevated CO2 no banding of Mg is recognisable and overall Mg concentrations are lower. This reduction in Mg in the carbonate undermines the accuracy of the Mg/Ca ratio as proxy for past temperatures in time intervals with significantly different carbonate chemistry. Fundamentally, the loss of Mg in the calcite may reduce elasticity thereby changing the structural properties, which may affect the ability of L. glaciale to efficiently function as a habitat former in the future 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 2016-10-31.