Interpreting the role of pH on stable isotopes in large benthic foraminifera, supplement to: Robbins, Lisa L; Knorr, Paul O; Wynn, Jonathan G; Hallock, Pamela; Harries, P J (2016): Interpreting the role of pH on stable isotopes in large benthic foraminifera. ICES Journal of Marine Science, fsw056

• Main Authors: Robbins, Lisa L, Knorr, Paul O, Wynn, Jonathan G, Hallock, Pamela, Harries, P J
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2017
• Subjects: Amphistegina gibbosa; Archaias angulatus; Benthos; Chromista; Coast and continental shelf; Foraminifera; Heterotrophic prokaryotes; Laboratory experiment; North Atlantic; Other studied parameter or process; Single species; Temperate; Type; Species; Registration number of species; Uniform resource locator/link to reference; Treatment; Sample type; Replicates; δ18O; δ18O, standard deviation; δ13C; δ13C, standard deviation; pH; pH, standard deviation; Carbon, inorganic, dissolved; Alkalinity, total; Alkalinity, total, standard deviation; Partial pressure of carbon dioxide water at sea surface temperature wet air; Calcite saturation state; Temperature, water; Temperature, water, standard deviation; Salinity; Salinity, standard deviation; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Aragonite saturation state; Spectrophotometric; Calculated using CO2calc; Potentiometric titration; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.869319; https://doi.pangaea.de/10.1594/PANGAEA.869319

Large benthic foraminifera (LBF) are prolific producers of calcium carbonate sediments in shallow, tropical environments that are being influenced by ocean acidification (OA). Two LBF species, Amphistegina gibbosa (Order Rotaliida) with low-Mg calcite tests and Archaias angulatus (Order Miliolida) with high-Mg calcite tests, were studied to assess the effects of pH 7.6 on oxygen and carbon isotopic fractionation between test calcite and ambient seawater. The delta 18O and delta 13C values of terminal chambers and of whole adult tests of both species after 6 weeks were not significantly different between pH treatments of 8.0 and 7.6. However, tests of juveniles produced during the 6-week treatments showed significant differences between delta 18O and delta 13C values from control (pH 8.0) when compared with the treatment (pH 7.6) for both species. Although each individual's growth was photographed and measured, difficulty in distinguishing and manually extracting newly precipitated calcite from adult specimens likely confounded any differences in isotopic signals. However, juvenile specimens that resulted from asexual reproduction that occurred during the experiments did not contain old carbonate that could confound the new isotopic signals. These data reveal a potential bias in the design of OA experiments if only adults are used to investigate changes in test chemistries. Furthermore, the results reaffirm that different calcification mechanisms in these two foraminiferal orders control the fractionation of stable isotopes in the tests and will reflect decreasing pH in seawater somewhat differently. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2016) 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 2016-12-12.