Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica
Core top samples from Indonesian and northeast Atlantic depth transects were used to calibrate Mg/Ca and δ18O in tests of the calcitic benthic foraminifer Hyalinea balthica to bottom water temperature between 4°C and 13°C. This shallow infaunal species is primarily abundant in neritic to upper bathy...
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American Geophysical Union
2011
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Online Access: | http://okina.univ-angers.fr/publications/ua3896 https://doi.org/10.1029/2010GC003333 |
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ftunivangokina:oai:okina.univ-angers.fr:3896 2023-05-15T17:41:41+02:00 Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica Y. Rosenthal A. Morley C. Barras M.E. Katz F. Jorissen G.J. Reichart D.W. Oppo B.K. Linsley 2011 http://okina.univ-angers.fr/publications/ua3896 https://doi.org/10.1029/2010GC003333 eng eng American Geophysical Union Geochemistry, Geophysics, Geosystems Article scientifique dans une revue à comité de lecture 2011 ftunivangokina https://doi.org/10.1029/2010GC003333 2017-04-13T17:49:00Z Core top samples from Indonesian and northeast Atlantic depth transects were used to calibrate Mg/Ca and δ18O in tests of the calcitic benthic foraminifer Hyalinea balthica to bottom water temperature between 4°C and 13°C. This shallow infaunal species is primarily abundant in neritic to upper bathyal sediments (<600 m). Both linear and exponential calibrations suggest a temperature sensitivity of ∼12% per °C that is ∼4 times higher than observed in other species of deep-sea benthic foraminifera. Culture experiments support the core top calibration. We find no discernible effect of salinity and saturation on Mg/Ca. Comparison between the measured benthic foraminiferal δ18O and predicted equilibrium values suggests that on average H. balthica δ18O is 0.64‰ ± 0.13‰ lower than predicted from the equilibrium composition. To test the reliability of using paired H. balthica Mg/Ca and δ18O measurements for reconstructing seawater δ18Osw and salinity, we apply this calibration to another depth transect from Cape Ghir off NW Africa, which was not included in the calibration. Based on error analysis of the calibration data and this validation test, we show that the uncertainty of reconstructing bottom water temperature and salinity from paired Mg/Ca and δ18O measurements of H. balthica is better than ±0.7°C and ±0.69 practical salinity scale, respectively. The small uncertainties allow for the reconstruction of seawater density to better than 0.3σθ units, which is precise enough for the identification of specific water masses and reconstruction of changes in their properties. We propose that the relatively high Mg content and temperature sensitivity of H. balthica might be due to minor, biologically mediated contribution of high-Mg calcite to the primarily low Mg calcite test, which is influenced by the ambient temperature. This hypothesis, if correct, suggests that benthic species with relatively high Mg/Ca may be better suited for deepwater temperature reconstructions than species that have thus far been more commonly used. Article in Journal/Newspaper Northeast Atlantic Université Angers: Okina (Open Knowledge, INformation, Access) Geochemistry, Geophysics, Geosystems 12 4 n/a n/a |
institution |
Open Polar |
collection |
Université Angers: Okina (Open Knowledge, INformation, Access) |
op_collection_id |
ftunivangokina |
language |
English |
description |
Core top samples from Indonesian and northeast Atlantic depth transects were used to calibrate Mg/Ca and δ18O in tests of the calcitic benthic foraminifer Hyalinea balthica to bottom water temperature between 4°C and 13°C. This shallow infaunal species is primarily abundant in neritic to upper bathyal sediments (<600 m). Both linear and exponential calibrations suggest a temperature sensitivity of ∼12% per °C that is ∼4 times higher than observed in other species of deep-sea benthic foraminifera. Culture experiments support the core top calibration. We find no discernible effect of salinity and saturation on Mg/Ca. Comparison between the measured benthic foraminiferal δ18O and predicted equilibrium values suggests that on average H. balthica δ18O is 0.64‰ ± 0.13‰ lower than predicted from the equilibrium composition. To test the reliability of using paired H. balthica Mg/Ca and δ18O measurements for reconstructing seawater δ18Osw and salinity, we apply this calibration to another depth transect from Cape Ghir off NW Africa, which was not included in the calibration. Based on error analysis of the calibration data and this validation test, we show that the uncertainty of reconstructing bottom water temperature and salinity from paired Mg/Ca and δ18O measurements of H. balthica is better than ±0.7°C and ±0.69 practical salinity scale, respectively. The small uncertainties allow for the reconstruction of seawater density to better than 0.3σθ units, which is precise enough for the identification of specific water masses and reconstruction of changes in their properties. We propose that the relatively high Mg content and temperature sensitivity of H. balthica might be due to minor, biologically mediated contribution of high-Mg calcite to the primarily low Mg calcite test, which is influenced by the ambient temperature. This hypothesis, if correct, suggests that benthic species with relatively high Mg/Ca may be better suited for deepwater temperature reconstructions than species that have thus far been more commonly used. |
format |
Article in Journal/Newspaper |
author |
Y. Rosenthal A. Morley C. Barras M.E. Katz F. Jorissen G.J. Reichart D.W. Oppo B.K. Linsley |
spellingShingle |
Y. Rosenthal A. Morley C. Barras M.E. Katz F. Jorissen G.J. Reichart D.W. Oppo B.K. Linsley Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica |
author_facet |
Y. Rosenthal A. Morley C. Barras M.E. Katz F. Jorissen G.J. Reichart D.W. Oppo B.K. Linsley |
author_sort |
Y. Rosenthal |
title |
Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica |
title_short |
Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica |
title_full |
Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica |
title_fullStr |
Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica |
title_full_unstemmed |
Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica |
title_sort |
temperature calibration of mg/ca ratios in the intermediate water benthic foraminifer hyalinea balthica |
publisher |
American Geophysical Union |
publishDate |
2011 |
url |
http://okina.univ-angers.fr/publications/ua3896 https://doi.org/10.1029/2010GC003333 |
genre |
Northeast Atlantic |
genre_facet |
Northeast Atlantic |
op_source |
Geochemistry, Geophysics, Geosystems |
op_doi |
https://doi.org/10.1029/2010GC003333 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
12 |
container_issue |
4 |
container_start_page |
n/a |
op_container_end_page |
n/a |
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1766143367986544640 |