Assessing the reliability of magnesium in foraminiferal calcite as a proxy for water mass temperatures

Nürnberg, Dirk; Biȷma, Jelle; Hemleben, Christoph

doi:10.1016/0016-7037(95)00446-7

Cited by 735 publications

(788 citation statements)

References 43 publications

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“…Our results correspond to a temperature of 26°C and variable salinities, ranging from 30 to 39. Mg/Ca ratios measured on chambers 18 of G. sacculifer show slightly higher values compared to previous studies (Nürnberg et al, 1996b;Anand et al, 2003) (Fig. 2A).…”

Section: Resultscontrasting

confidence: 69%

“…Overall the test carbonate of G. sacculifer has lower Mg/Ca ratios (this study; Nürnberg et al, 1996b;Anand et al, 2003) compared to O. universa and Globigerinoides bulloides Elderfield and Ganssen, 2000;McConnell and Thunell, 2005;Russell et al, 2004). Mg/Ca ratios in the tests of G. sacculifer and Globigerinoides ruber (white) (Kısakürek et al, 2008) show similar values ( Fig.…”

Section: Resultssupporting

confidence: 52%

“…Accurate temperature reconstructions, therefore, rely on an understanding of these additional factors that can potentially influence the incorporation of Mg and Sr in foraminiferal calcite. Through culture experiments salinity showed to exert a small but consistent influence on foraminiferal Mg/Ca ratios (Nürnberg et al, 1996a;Lea et al, 1999;Kısakürek et al, 2008). More recently, Ferguson etal.…”

Section: Introductionmentioning

confidence: 90%

“…Chambers corresponding to other life stages (i.e. 19 and 20) are not taken into account in the present study because ontogeny potentially plays an important role in determining their chemical composition (Nürnberg et al, 1996a;Eggins et al, 2003;Erez, 2003).…”

Section: Foraminifera Collection and Culturingmentioning

confidence: 99%

“…Over the past two decades temperature reconstructions have become increasingly reliant on Mg/Ca ratios measured on planktonic and benthic foraminiferal shells (Nürnberg et al, 1996a;Lea et al, 1999;Russell et al, 2004;Rosenthal et al, 2006;Yu and Elderfield, 2008). The incorporation of Sr into foraminiferal calcite may also show temperature dependence Reichart et al, 2003;Mortyn et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Effect of salinity and seawater calcite saturation state on Mg and Sr incorporation in cultured planktonic foraminifera

Dueñas-Bohórquez

Rocha

Kuroyanagi

et al. 2009

Marine Micropaleontology

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100

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Section: Resultscontrasting

confidence: 69%

Section: Resultssupporting

confidence: 52%

Section: Introductionmentioning

confidence: 90%

Section: Foraminifera Collection and Culturingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of salinity and seawater calcite saturation state on Mg and Sr incorporation in cultured planktonic foraminifera

Dueñas-Bohórquez

Rocha

Kuroyanagi

et al. 2009

Marine Micropaleontology

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100

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Seawater Temperature Estimates in Paleoceanography

Cortese

2004

Water Encyclopedia

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Temperature, together with salinity, determines the density of seawater, and therefore, it strongly influences its circulation and sinking characteristics. In turn, the important role oceanic circulation and deep‐water formation play in past, present, and future climatic change lend a special significance to the estimate of past seawater temperature. As the past values of this important climatic variable in the distant, geological past are impossible to measure directly, a variety of indirect methods, so‐called “proxies,” have been developed. These methods are usually based on the fossil faunal/floral composition of sediment core samples, as a close link exists between species occurrences/abundances and environmental variables. Semiquantitative (e.g., faunal provinces indexes) and quantitative (e.g., transfer functions, neural networks) techniques are therefore applied to reconstruct past sea surface water variables, including temperature. Additionally, several geochemical methods have been recently developed to estimate past ocean temperatures by measuring chemical elements (Mg/Ca, Sr/Ca) or organic compounds (alkenones), which are either incorporated in the organism shell, or produced during its life cycle.

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An interlaboratory study of TEX₈₆ and BIT analysis of sediments, extracts, and standard mixtures

Schouten

Hopmans

Rosell-Melé

et al. 2013

Geochem Geophys Geosyst

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[2] Two commonly used proxies based on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) are the TEX 86 (TetraEther indeX of 86 carbon atoms) paleothermometer for sea surface temperature reconstructions and the BIT (Branched Isoprenoid Tetraether) index for reconstructing soil organic matter input to the ocean. An initial round-robin study of two sediment extracts, in which 15 laboratories participated, showed relatively consistent TEX 86 values (reproducibility 63-4 C when translated to temperature) but a large spread in BIT measurements (reproducibility 60.41 on a scale of 0-1). Here we report results of a second round-robin study with 35 laboratories in which three sediments, one sediment extract, and two mixtures of pure, isolated GDGTs were analyzed. The results for TEX 86 and BIT index showed improvement compared to the previous round-robin study. The reproducibility, indicating interlaboratory variation, of TEX 86 values ranged from 1.3 to 3.0 C when translated to temperature. These results are similar to those of other temperature proxies used in paleoceanography. Comparison of the results obtained from one of the three sediments showed that TEX 86 and BIT indices are not significantly affected by interlaboratory differences in sediment extraction techniques. BIT values of the sediments and extracts were at the extremes of the index with values close to 0 or 1, and showed good reproducibility (ranging from 0.013 to 0.042). However, the measured BIT values for the two GDGT mixtures, with known molar ratios of crenarchaeol and branched GDGTs, had intermediate BIT values and showed poor reproducibility and a large overestimation of the ''true'' (i.e., molarbased) BIT index. The latter is likely due to, among other factors, the higher mass spectrometric response of branched GDGTs compared to crenarchaeol, which also varies among mass spectrometers. Correction for this different mass spectrometric response showed a considerable improvement in the reproducibility of BIT index measurements among laboratories, as well as a substantially improved estimation of molar-based BIT values. This suggests that standard mixtures should be used in order to obtain consistent, and molar-based, BIT values.

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Assessing the reliability of magnesium in foraminiferal calcite as a proxy for water mass temperatures

Cited by 735 publications

References 43 publications

Effect of salinity and seawater calcite saturation state on Mg and Sr incorporation in cultured planktonic foraminifera

Effect of salinity and seawater calcite saturation state on Mg and Sr incorporation in cultured planktonic foraminifera

Seawater Temperature Estimates in Paleoceanography

An interlaboratory study of TEX₈₆ and BIT analysis of sediments, extracts, and standard mixtures

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Assessing the reliability of magnesium in foraminiferal calcite as a proxy for water mass temperatures

Cited by 735 publications

References 43 publications

Effect of salinity and seawater calcite saturation state on Mg and Sr incorporation in cultured planktonic foraminifera

Effect of salinity and seawater calcite saturation state on Mg and Sr incorporation in cultured planktonic foraminifera

Seawater Temperature Estimates in Paleoceanography

An interlaboratory study of TEX86 and BIT analysis of sediments, extracts, and standard mixtures

Contact Info

Product

Resources

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An interlaboratory study of TEX₈₆ and BIT analysis of sediments, extracts, and standard mixtures