Modulation and daily banding of Mg/Ca in tests by symbiont photosynthesis and respiration: a complication for seawater thermometry?

Eggins, Stephen; Sadekov, Aleksey; Deckker, Patrick De

doi:10.1016/j.epsl.2004.06.019

Cited by 199 publications

(234 citation statements)

References 35 publications

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“…The participation of a small volume of seawater at the beginning of chamber formation may explain the elevated Mg in the first calcite precipitated, although this pattern does not hold for other planktonic species (e.g. such as O. universa; Eggins et al, 2004) where the lowest Mg/Ca ratios are associated with the intrashell zone that corresponds to the POS. The above observations of inter species differences in chamber wall elemental composition underscore the need to unravel the mechanisms controlling test calcification.…”

Section: Organic Templates and Nucleation Of Caco 3 In Foraminiferamentioning

confidence: 95%

Biomineralization in perforate foraminifera

Nooijer

Spero

Erez

et al. 2014

Earth-Science Reviews

202

190

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a b s t r a c t a r t i c l e i n f oIn this paper, we review the current understanding of biomineralization in perforate foraminifera. Ideas on the mechanisms responsible for the flux of Ca 2+ and inorganic carbon from seawater into the test were originally based on light and electron microscopic observations of calcifying foraminifera. From the 1980s onward, tracer experiments, fluorescent microscopy and high-resolution test geochemical analysis have added to existing calcification models. Despite recent insights, no general consensus on the physiological basis of foraminiferal biomineralization exists. Current models include seawater vacuolization, transmembrane ion transport, involvement of organic matrices and/or pH regulation, although the magnitude of these controls remain to be quantified. Disagreement between currently available models may be caused by the use of different foraminiferal species as subject for biomineralization experiments and/or lack of a more systematic approach to study (dis)similarities between taxa. In order to understand foraminiferal controls on element incorporation and isotope fractionation, and thereby improve the value of foraminifera as paleoceanographic proxies, it is necessary to identify key processes in foraminiferal biomineralization and formulate hypotheses regarding the involved physiological pathways to provide directions for future research.

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Section: Organic Templates and Nucleation Of Caco 3 In Foraminiferamentioning

confidence: 95%

Biomineralization in perforate foraminifera

Nooijer

Spero

Erez

et al. 2014

Earth-Science Reviews

202

190

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“…In the ideal case, each time a new chamber is added the older chambers are covered by an additional layer of calcite (Erez, 2003;Hemleben et al, 1977;Reiss, 1957), resulting in a laminated structure. Mg/Ca (and other trace element) banding has been observed in this laminar calcite (Eggins et al, 2004;Erez, 2003;Hathorne et al, 2009;Kunioka et al, 2006;Sadekov et al, 2005). Yet, this intratest Mg/Ca heterogeneity is too large to be caused by temperature variability experienced during the growth of the foraminiferal test and Eggins et al (2004) attributed such banding in the final chamber of Orbulina universa to pH changes as a result of diurnal changes in endosymbiont activity.…”

Section: Introductionmentioning

confidence: 97%

“…Mg/Ca (and other trace element) banding has been observed in this laminar calcite (Eggins et al, 2004;Erez, 2003;Hathorne et al, 2009;Kunioka et al, 2006;Sadekov et al, 2005). Yet, this intratest Mg/Ca heterogeneity is too large to be caused by temperature variability experienced during the growth of the foraminiferal test and Eggins et al (2004) attributed such banding in the final chamber of Orbulina universa to pH changes as a result of diurnal changes in endosymbiont activity. However, similar banding was later also observed in symbiont-barren species, indicating that other mechanisms are required (Hathorne et al, 2009).…”

Section: Introductionmentioning

confidence: 97%

“…Others have also shown that high Mg/Ca bands do not occur at the location of organic layers, rendering this explanation for intratest trace element banding unlikely (Eggins et al, 2004;Sadekov et al, 2005;Spero et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…However, Mg/Catemperature relationships are species specific and remain (largely) empirical and many studies have shown a tight biological control on Mg incorporation in foraminiferal calcite (Anand et al, 2003;Bentov and Erez, 2006;de Nooijer et al, 2014;Jonkers et al, 2012;Jonkers et al, 2013a;Lea et al, 1999;Spero et al, 2015). In particular, the Mg distribution within single foraminifera tests shows large, non-temperature related variability (Eggins et al, 2003;Eggins et al, 2004;Kunioka et al, 2006;Sadekov et al, 2005). Accurate paleotemperature reconstructions thus require a solid understanding of the nature of and controls on such variability.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Chamber formation leads to Mg/Ca banding in the planktonic foraminifer Neogloboquadrina pachyderma

Jonkers

Buse

Brummer

et al. 2016

Earth and Planetary Science Letters

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms Additionally, all specimens are covered with an outer crust consisting of large euhedral crystals. The composition of the crust is similar to the low Mg/Ca bands in the laminar calcite in winter and summer specimens, indicating a tight biological control on crust formation and composition.Nevertheless, despite high intratest variability, the median Mg/Ca of summertime tests is higher than that of wintertime tests. This provides support for Mg/Ca paleothermometry, but to improve the accuracy of paleotemperature estimates biological effects on Mg incorporation need to be better accounted for.

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Exploring the dissolution effect on the intrashell Mg/Ca variability of the planktic foraminifer Globigerinoides ruber

Fehrenbacher

Martin

2014

Paleoceanography

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The Mg/Ca ratio of the planktic foraminifer Globigerinoides ruber is widely used for reconstructing past sea surface temperatures. The shell Mg/Ca ratio is also lowered by dissolution, which results in lower sea surface temperature estimates in partially dissolved shells. Here we use an electron microprobe image mapping technique to map the intrashell variability of the Mg/Ca ratio in G. ruber (white) sensu stricto shells to explore changes in the intrashell Mg/Ca ratio associated with dissolution. We examine shells from shallow and deep cores (Ceara Rise, western tropical Atlantic) from the Holocene and Last Glacial Maximum that represent a preservational gradient. Image map results show that the Mg/Ca ratio is highly variable both within a single shell and among samples obtained from the same sediment interval. Our results show that intrashell Mg/Ca variability is retained in samples that have undergone dissolution. Quantitative analysis of the data from Mg/Ca mapping suggests that preferential loss of high-Mg/Ca calcite alone cannot account for the difference in intrashell Mg/Ca variability of shells from shallow and deep cores in both time periods. Rather, the data imply that, in G. ruber analyzed in this study, there is a loss of high Mg/Ca ratios accompanied by a more uniform lowering of Mg/Ca over the range of intershell Mg/Ca variability of shells subjected to dissolution at the 1 μm resolution of the microprobe analysis in this study.

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Modulation and daily banding of Mg/Ca in tests by symbiont photosynthesis and respiration: a complication for seawater thermometry?

Cited by 199 publications

References 35 publications

Biomineralization in perforate foraminifera

Biomineralization in perforate foraminifera

Chamber formation leads to Mg/Ca banding in the planktonic foraminifer Neogloboquadrina pachyderma

Exploring the dissolution effect on the intrashell Mg/Ca variability of the planktic foraminifer Globigerinoides ruber

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