Publication Date:
2024-03-15
Description:
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.
Keywords:
Alkalinity, total; Alkalinity, total, standard deviation; Amphistegina gibbosa; Aragonite saturation state; Archaias angulatus; Benthos; Bicarbonate ion; Calcite saturation state; Calculated using CO2calc; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chromista; Coast and continental shelf; Foraminifera; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Heterotrophic prokaryotes; Laboratory experiment; North Atlantic; OA-ICC; Ocean Acidification International Coordination Centre; Other studied parameter or process; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; pH, standard deviation; Potentiometric titration; Registration number of species; Replicates; Salinity; Salinity, standard deviation; Sample type; Single species; Species; Spectrophotometric; Temperate; Temperature, water; Temperature, water, standard deviation; Treatment; Type; Uniform resource locator/link to reference; δ13C; δ13C, standard deviation; δ18O; δ18O, standard deviation
Type:
Dataset
Format:
text/tab-separated-values, 396 data points
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