What question did this study set out to answer?

To reexamine temperature-to-δ18O relationships in cultured planktonic foraminifera across 15°–25°C and develop revised paleotemperature equations.

April 1, 1998Paleoceanography

Reevaluation of the oxygen isotopic composition of planktonic foraminifera: Experimental results and revised paleotemperature equations

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Authors

BBBryan E. BemisUniversity of Wisconsin–Madison HSHoward J. SperoPlanetary Science Institute JBJelle BijmaAlfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

Discussion

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Implication

Culture experiment demonstrates refined oxygen isotope paleotemperature calibrations in planktonic foraminifera, highlighting light and size effects on ocean temperature reconstructions.

Key Points

To reexamine temperature-to-δ18O relationships in cultured planktonic foraminifera across 15°–25°C and develop revised paleotemperature equations.
Cultured symbiotic Orbulina universa and nonsymbiotic Globigerina bulloides under controlled laboratory water temperatures ranging between 15°C and 25°C.
Evaluated the influence of light levels (low light vs. high light), dissolved carbonate ion concentrations, and shell size on calcite δ18O fractionation.
Compared experimental calibrations against field data from modern plankton tows, sediment core tops, and benthic Cibicidoides records.
O. universa exhibited a linear temperature:δ18O slope of −4.80 (0.21‰ °C⁻¹), with high-light conditions causing a −0.33‰ offset compared to low-light growth due to symbiont photosynthesis.
Dissolved carbonate concentration reduced O. universa δ18O by −0.002‰ µmol⁻¹ kg⁻¹ independently of temperature, whereas G. bulloides displayed size-dependent ontogenetic enrichment in 18O.
The revised O. universa calibrations improved accuracy over previous equations for plankton tow data and matched benthic data below 10°C, while G. bulloides equations matched northeast Pacific field data.

Cite This Study

Bemis et al. (1998) studied this question.

synapsesocial.com/papers/6a0316971abe013fb89e39c6 https://doi.org/10.1029/98pa00070

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Implication

Culture experiment demonstrates refined oxygen isotope paleotemperature calibrations in planktonic foraminifera, highlighting light and size effects on ocean temperature reconstructions.

Reevaluation of the oxygen isotopic composition of planktonic foraminifera: Experimental results and revised paleotemperature equations

Discussion

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Implication

Key Points

Cite This Study

Reevaluation of the oxygen isotopic composition of planktonic foraminifera: Experimental results and revised paleotemperature equations

Discussion

Member takes

Implication

Key Points

Cite This Study

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