Mg/Ca-Temperature Calibration of Polar Benthic Foraminifera Species for Reconstruction of Bottom Water Temperatures on the Antarctic Shelf

Elaine M. Mawbey; Katharine R. Hendry; Mervyn J. Greaves; Claus-Dieter Hillenbrand; Gerhard Kuhn; Charlotte L. Spencer-Jones; Erin L. McClymont; Kara J. Vadman; Amelia E. Shevenell; Patrycja E. Jernas; James A. Smith

doi:10.1016/j.gca.2020.05.027

Mg/Ca-Temperature Calibration of Polar Benthic Foraminifera Species for Reconstruction of Bottom Water Temperatures on the Antarctic Shelf

Elaine M. Mawbey, Katharine R. Hendry, Mervyn J. Greaves, Claus-Dieter Hillenbrand, Gerhard Kuhn, Charlotte L. Spencer-Jones, Erin L. McClymont, Kara J. Vadman, Amelia E. Shevenell, Patrycja E. Jernas, James A. Smith

College of Marine Science

Research output: Contribution to journal › Article › peer-review

Abstract

Benthic foraminifera Mg/Ca is a well-established bottom water temperature (BWT) proxy used in paleoclimate studies. The relationship between Mg/Ca and BWT for numerous species has been determined using core-top and culturing studies. However, the scarcity of calcareous microfossils in Antarctic shelf sediments and poorly defined calibrations at low temperatures has limited the use of the foraminiferal Mg/Ca paleothermometer in ice proximal Antarctic sediments. Here we present paired ocean temperature and modern benthic foraminifera Mg/Ca data for three species, Trifarina angulosa , Bulimina aculeata , and Globocassidulina subglobosa, but with a particular focus on Trifarina angulosa. The core-top data from several Antarctic sectors span a BWT range of −1.7 to +1.2 °C and constrain the relationship between Mg/Ca and cold temperatures. We compare our results to published lower-latitude core-top data for species in the same or related genera, and in the case of Trifarina angulosa, produce a regional calibration. The resulting regional equation for Trifarina angulosa is Temperature (°C) = (Mg/Ca −1.14 ± 0.035)/0.069 ± 0.033). Addition of our Trifarina angulosa data to the previously published Uvigerina spp . dataset provides an alternative global calibration, although some data points appear to be offset from this relationship and are discussed. Mg-temperature relationships for Bulimina aculeata and Globocassidulina subglobosa are also combined with previously published data to produce calibration equations of Temperature (°C) = (Mg/Ca-1.04 ± 0.07)/0.099 ± 0.01 and Temperature (°C) = (Mg/Ca-0.99 ± 0.03)/0.087 ± 0.01, respectively. These refined calibrations highlight the potential utility of benthic foraminifera Mg/Ca-paleothermometry for reconstructing past BWT in Antarctic margin settings.

Original language	American English
Journal	Geochimica et Cosmochimica Acta
Volume	283
DOIs	https://doi.org/10.1016/j.gca.2020.05.027
State	Published - Jan 1 2020

Keywords

Mg/Ca-temperature calibration
Benthic foraminifera
Antarctica
Paleotemperature reconstruction
Core-tops

Disciplines

Life Sciences

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Mawbey, E. M., Hendry, K. R., Greaves, M. J., Hillenbrand, C.-D., Kuhn, G., Spencer-Jones, C. L., McClymont, E. L., Vadman, K. J., Shevenell, A. E., Jernas, P. E., & Smith, J. A. (2020). Mg/Ca-Temperature Calibration of Polar Benthic Foraminifera Species for Reconstruction of Bottom Water Temperatures on the Antarctic Shelf. Geochimica et Cosmochimica Acta, 283. https://doi.org/10.1016/j.gca.2020.05.027

Mawbey, EM, Hendry, KR, Greaves, MJ, Hillenbrand, C-D, Kuhn, G, Spencer-Jones, CL, McClymont, EL, Vadman, KJ, Shevenell, AE, Jernas, PE & Smith, JA 2020, 'Mg/Ca-Temperature Calibration of Polar Benthic Foraminifera Species for Reconstruction of Bottom Water Temperatures on the Antarctic Shelf', Geochimica et Cosmochimica Acta, vol. 283. https://doi.org/10.1016/j.gca.2020.05.027

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title = "Mg/Ca-Temperature Calibration of Polar Benthic Foraminifera Species for Reconstruction of Bottom Water Temperatures on the Antarctic Shelf",

abstract = " Benthic foraminifera Mg/Ca is a well-established bottom water temperature (BWT) proxy used in paleoclimate studies. The relationship between Mg/Ca and BWT for numerous species has been determined using core-top and culturing studies. However, the scarcity of calcareous microfossils in Antarctic shelf sediments and poorly defined calibrations at low temperatures has limited the use of the foraminiferal Mg/Ca paleothermometer in ice proximal Antarctic sediments. Here we present paired ocean temperature and modern benthic foraminifera Mg/Ca data for three species, Trifarina angulosa , Bulimina aculeata , and Globocassidulina subglobosa, but with a particular focus on Trifarina angulosa. The core-top data from several Antarctic sectors span a BWT range of −1.7 to +1.2 °C and constrain the relationship between Mg/Ca and cold temperatures. We compare our results to published lower-latitude core-top data for species in the same or related genera, and in the case of Trifarina angulosa, produce a regional calibration. The resulting regional equation for Trifarina angulosa is Temperature (°C) = (Mg/Ca −1.14 ± 0.035)/0.069 ± 0.033). Addition of our Trifarina angulosa data to the previously published Uvigerina spp . dataset provides an alternative global calibration, although some data points appear to be offset from this relationship and are discussed. Mg-temperature relationships for Bulimina aculeata and Globocassidulina subglobosa are also combined with previously published data to produce calibration equations of Temperature (°C) = (Mg/Ca-1.04 ± 0.07)/0.099 ± 0.01 and Temperature (°C) = (Mg/Ca-0.99 ± 0.03)/0.087 ± 0.01, respectively. These refined calibrations highlight the potential utility of benthic foraminifera Mg/Ca-paleothermometry for reconstructing past BWT in Antarctic margin settings. ",

keywords = "Mg/Ca-temperature calibration, Benthic foraminifera, Antarctica, Paleotemperature reconstruction, Core-tops",

author = "Mawbey, {Elaine M.} and Hendry, {Katharine R.} and Greaves, {Mervyn J.} and Claus-Dieter Hillenbrand and Gerhard Kuhn and Spencer-Jones, {Charlotte L.} and McClymont, {Erin L.} and Vadman, {Kara J.} and Shevenell, {Amelia E.} and Jernas, {Patrycja E.} and Smith, {James A.}",

year = "2020",

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doi = "10.1016/j.gca.2020.05.027",

language = "American English",

volume = "283",

journal = "Geochimica et Cosmochimica Acta",

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TY - JOUR

T1 - Mg/Ca-Temperature Calibration of Polar Benthic Foraminifera Species for Reconstruction of Bottom Water Temperatures on the Antarctic Shelf

AU - Mawbey, Elaine M.

AU - Hendry, Katharine R.

AU - Greaves, Mervyn J.

AU - Hillenbrand, Claus-Dieter

AU - Kuhn, Gerhard

AU - Spencer-Jones, Charlotte L.

AU - McClymont, Erin L.

AU - Vadman, Kara J.

AU - Shevenell, Amelia E.

AU - Jernas, Patrycja E.

AU - Smith, James A.

PY - 2020/1/1

Y1 - 2020/1/1

N2 - Benthic foraminifera Mg/Ca is a well-established bottom water temperature (BWT) proxy used in paleoclimate studies. The relationship between Mg/Ca and BWT for numerous species has been determined using core-top and culturing studies. However, the scarcity of calcareous microfossils in Antarctic shelf sediments and poorly defined calibrations at low temperatures has limited the use of the foraminiferal Mg/Ca paleothermometer in ice proximal Antarctic sediments. Here we present paired ocean temperature and modern benthic foraminifera Mg/Ca data for three species, Trifarina angulosa , Bulimina aculeata , and Globocassidulina subglobosa, but with a particular focus on Trifarina angulosa. The core-top data from several Antarctic sectors span a BWT range of −1.7 to +1.2 °C and constrain the relationship between Mg/Ca and cold temperatures. We compare our results to published lower-latitude core-top data for species in the same or related genera, and in the case of Trifarina angulosa, produce a regional calibration. The resulting regional equation for Trifarina angulosa is Temperature (°C) = (Mg/Ca −1.14 ± 0.035)/0.069 ± 0.033). Addition of our Trifarina angulosa data to the previously published Uvigerina spp . dataset provides an alternative global calibration, although some data points appear to be offset from this relationship and are discussed. Mg-temperature relationships for Bulimina aculeata and Globocassidulina subglobosa are also combined with previously published data to produce calibration equations of Temperature (°C) = (Mg/Ca-1.04 ± 0.07)/0.099 ± 0.01 and Temperature (°C) = (Mg/Ca-0.99 ± 0.03)/0.087 ± 0.01, respectively. These refined calibrations highlight the potential utility of benthic foraminifera Mg/Ca-paleothermometry for reconstructing past BWT in Antarctic margin settings.

AB - Benthic foraminifera Mg/Ca is a well-established bottom water temperature (BWT) proxy used in paleoclimate studies. The relationship between Mg/Ca and BWT for numerous species has been determined using core-top and culturing studies. However, the scarcity of calcareous microfossils in Antarctic shelf sediments and poorly defined calibrations at low temperatures has limited the use of the foraminiferal Mg/Ca paleothermometer in ice proximal Antarctic sediments. Here we present paired ocean temperature and modern benthic foraminifera Mg/Ca data for three species, Trifarina angulosa , Bulimina aculeata , and Globocassidulina subglobosa, but with a particular focus on Trifarina angulosa. The core-top data from several Antarctic sectors span a BWT range of −1.7 to +1.2 °C and constrain the relationship between Mg/Ca and cold temperatures. We compare our results to published lower-latitude core-top data for species in the same or related genera, and in the case of Trifarina angulosa, produce a regional calibration. The resulting regional equation for Trifarina angulosa is Temperature (°C) = (Mg/Ca −1.14 ± 0.035)/0.069 ± 0.033). Addition of our Trifarina angulosa data to the previously published Uvigerina spp . dataset provides an alternative global calibration, although some data points appear to be offset from this relationship and are discussed. Mg-temperature relationships for Bulimina aculeata and Globocassidulina subglobosa are also combined with previously published data to produce calibration equations of Temperature (°C) = (Mg/Ca-1.04 ± 0.07)/0.099 ± 0.01 and Temperature (°C) = (Mg/Ca-0.99 ± 0.03)/0.087 ± 0.01, respectively. These refined calibrations highlight the potential utility of benthic foraminifera Mg/Ca-paleothermometry for reconstructing past BWT in Antarctic margin settings.

KW - Mg/Ca-temperature calibration

KW - Benthic foraminifera

KW - Antarctica

KW - Paleotemperature reconstruction

KW - Core-tops

UR - https://digitalcommons.usf.edu/msc_facpub/2467

U2 - 10.1016/j.gca.2020.05.027

DO - 10.1016/j.gca.2020.05.027

M3 - Article

VL - 283

JO - Geochimica et Cosmochimica Acta

JF - Geochimica et Cosmochimica Acta

ER -

Mg/Ca-Temperature Calibration of Polar Benthic Foraminifera Species for Reconstruction of Bottom Water Temperatures on the Antarctic Shelf

Abstract

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