Seawater carbonate chemistry and carbon and oxygen isotopes during experiments with planktonic foraminifera Orbulina universa and Globigerina bulloides, 1997

• Main Authors: Spero, Howard J, Bijma, Jelle, Lea, David W, Bemis, E B
• Format: Dataset
• Language: English
• Published: PANGAEA 1997
• Subjects: Alkalinity; total; Aragonite saturation state; Bicarbonate ion; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chromista; Coast and continental shelf; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; EXP; Experiment; Experimental treatment; Foraminifera; planktic δ13C; planktic δ18O; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Globigerina bulloides; Heterotrophic prokaryotes; Isotope ratio mass spectrometry; Laboratory experiment; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Orbulina universa; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; Salinity; Sample ID; SFB261; Single species; South Atlantic in Late Quaternary: Reconstruction of Budget and Currents; Spero_etal_97; Temperate; Temperature; water; Pacific; Shackleton; Ocean acidification; Planktonic foraminifera
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.721923; https://doi.org/10.1594/PANGAEA.721923

Stable oxygen and carbon isotope measurements on biogenic calcite and aragonite have become standard tools for reconstructing past oceanographic and climatic change. In aquatic organisms, 18O/16O ratios in the shell carbonate are a function of the ratio in the sea water and the calcification temperature (Epstein et al., 1953). In contrast, 13C/12C ratios are controlled by the ratio of dissolved inorganic carbon in sea water and physiological processes such as respiration and symbiont photosynthesis (Spero et al., 1991, doi:10.1029/91PA02022). These geochemical proxies have been used with analyses of foraminifera shells to reconstruct global ice volumes (Shackleton and Opdyke, 1973, doi:10.1016/0033-5894(73)90052-5), surface and deep ocean temperatures (Broecker, 1986, doi:10.1016/0033-5894(86)90087-6; Labeyrie et al., 1987, doi:10.1038/327477a0), ocean circulation changes (Duplessy et al., 1988, doi:10.1029/PA003i003p00343) and glacial-interglacial exchange between the terrestrial and oceanic carbon pools (Sackleton, 1977). Here, we report experimental measurements on living symbiotic and non-symbiotic plankton foraminifera (Orbulina universa and Globigerina bulloides respectively) showing that the 13C/12C and 18O/16O ratios of the calcite shells decrease with increasing seawater [CO3 2-]. Because glacial-period oceans had higher pH and [CO3 2-] than today (Sanyal et al., 1995, doi:10.1038/373234a0), these new relationships confound the standard interpretation of glacial foraminiferal stable-isotope data. In particular, the hypothesis that the glacial-interglacial shift in the 13C/12C ratio was due to a transfer of terrestrial carbon into the ocean(Shackleton ,1977) can be explained alternatively by an increase in ocean alkalinity (Lea et al., 1996). A carbonate-concentration effect could also help explain some of the extreme stable-isotope variations during the Proterozoic and Phanerozoic aeons (Kaufman et al., 1993, doi:10.1016/0012-821X(93)90254-7).