Li partitioning in the benthic foraminifera <scp><i>A</i></scp><i>mphistegina lessonii</i>

Langer, Gerald; Sadekov, Aleksey; Thoms, Silke; Mewes, Antje; Nehrke, Gernot; Greaves, Mervyn; Misra, Sambuddha; Biȷma, Jelle; Elderfield, Henry

doi:10.1002/2015gc006134

Cited by 11 publications

(17 citation statements)

References 26 publications

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“…However, coccolith Li/Ca only increases if seawater Li concentration is increased, not if seawater Ca concentration is decreased. This pattern was also reported for A. lessonii (Langer et al, 2015). Hence, the Li partitioning pattern is the same in inorganically precipitated calcite (Marriott, Henderson, Belshaw, & Tudhope, 2004;Okumura & Kitano, 1986), A. lessonii (Langer et al, 2015) and E. huxleyi (this study).…”

Section: Resultssupporting

confidence: 87%

“…Since there are no published data on Li partitioning in coccolithophores, we conducted an experiment with E. huxleyi, similar in setup to the one performed on A. lessonii (Langer et al, 2015).…”

Section: Geochemistry Geophysics Geosystemsmentioning

confidence: 99%

“…The culture media were analyzed in the same manner as previously for A. lessonii culture experiments (Langer et al, 2015). Briefly, Li/Ca and Sr/Ca ratios were determined by ICP-OES after dilution of the culture media to a constant sodium concentration of 110 ppm.…”

Section: Analyses Of Culture Mediamentioning

confidence: 99%

“…Culture studies have shown that this assumption indeed holds true for Sr, not only in foraminifera but also in coccolithophores (Hermoso et al, 2017;Langer et al, 2006Langer et al, , 2016Mejía et al, 2018;Müller et al, 2018). However, while Mg partitioning into foraminiferal calcite shows a behavior similar to that of Sr partitioning (Mewes et al, 2014, foraminiferal Li/Ca does not depend on seawater Li/Ca but on seawater Li concentration (Langer et al, 2015). At first glance this difference between divalent cation Sr (Mg) and the alkali metal ion Li could be explained in terms of inorganic precipitation processes.…”

Section: Introductionmentioning

confidence: 99%

“…Li partitioning into foraminiferal calcite is a prime example. Although the pattern of Li partitioning into Amphistegina lessonii is explicable in terms of inorganic precipitation, an explanation based on transmembrane transport of ions was proposed (Langer et al, 2015). This explanation presupposes that foraminifera actually use transmembrane transport in order to deliver Ca ions to the site of calcification.…”

Section: Introductionmentioning

confidence: 99%

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Li Partitioning Into Coccoliths of Emiliania huxleyi: Evaluating the General Role of “Vital Effects” in Explaining Element Partitioning in Biogenic Carbonates

Langer

Sadekov

Greaves

et al. 2020

Geochem Geophys Geosyst

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Emiliania huxleyi cells were grown in artificial seawater of different Li and Ca concentrations and coccolith Li/Ca ratios determined. Coccolith Li/Ca ratios were positively correlated to seawater Li/Ca ratios only if the seawater Li concentration was changed, not if the seawater Ca concentration was changed. This Li partitioning pattern of E. huxleyi was previously also observed in the benthic foraminifer Amphistegina lessonii and inorganically precipitated calcite. We argue that Li partitioning in both E. huxleyi and A. lessonii is dominated by a coupled transmembrane transport of Li and Ca from seawater to the site of calcification. We present a refined version of a recently proposed transmembrane transport model for Li and Ca. The model assumes that Li and Ca enter the cell via Ca channels, the Li flux being dependent on the Ca flux. While the original model features a linear function to describe the experimental data, our refined version uses a power function, changing the stoichiometry of Li and Ca. The version presented here accurately predicts the observed dependence of DLi on seawater Li/Ca ratios. Our data demonstrate that minor element partitioning in calcifying organisms is partly mediated by biological processes even if the partitioning behavior of the calcifying organism is indistinguishable from that of inorganically precipitated calcium carbonate.

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Section: Resultssupporting

confidence: 87%

Section: Geochemistry Geophysics Geosystemsmentioning

confidence: 99%

Section: Analyses Of Culture Mediamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Li Partitioning Into Coccoliths of Emiliania huxleyi: Evaluating the General Role of “Vital Effects” in Explaining Element Partitioning in Biogenic Carbonates

Langer

Sadekov

Greaves

et al. 2020

Geochem Geophys Geosyst

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Coral Li/Mg thermometry: Caveats and constraints

et al. 2019

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The coral Li/Mg temperature proxy is revisited through an in-depth trace element analysis of scleractinians collected live from tropical to polar environments. The dataset consists of Li/Ca, Mg/Ca, Sr/Ca and Li/Mg ratios from 64 coral specimens belonging to 8 different taxa, including both reefbuilding zooxanthellate and coldwater non-zooxanthellate species, from a wide range of water temperature (−1 to 29.5 °C), salinity (34.71 to 38.61), and depth (3 to 670 m). Our results showed that the reliability of the Li/Mg temperature proxy is strongly limited by the organic matter associated with the coral skeleton, which is most evident within the green bands observed in tropical corals. Organicrich bands can double the Mg content otherwise present in the skeleton, which may ultimately lead to a temperature overestimation exceeding 15 °C. We found that this bias can be overcome by the treatment of coral skeletons with a specific oxidizing cleaning protocol. We also detected the presence of calcite deposits within the aragonite skeleton of some Antarctic living coral specimens, which strongly affects the robustness of the Li/Mg proxy given its temperature sensitivity of ~1.5 °C/1% calcite. Therefore, to obtain reliable reconstructions a correction needs to be applied when organic matter and/or calcite contamination is present, which requires the scrupulous assessment of the integrity of the aragonite prior to geochemical analyses. Given that some species entrap more organic matter than others, and that some are more prone to calcite contamination, a taxon-related effect is apparent. Here we show that the tropical species Porites spp., Pseudodiploria strigosa and Orbicella annularis, and the cold-water species Madrepora oculata, Caryophyllia antarctica and Flabellum impensum, are all suitable candidates for reconstructing seawater temperatures. The integrated results across a wide temperature range, from extreme cold to tropical shallow waters, yield an overall precision for the Li/Mg-temperature proxy of ± 1.0 °C, as quantified by the standard error of estimates. If calculated from the 95% prediction intervals, the uncertainty of the temperature estimates is ± 0.9 °C at 1 °C, ± 1.5 °C at 12 °C and ± 2.6 °C at 25 °C. However, the uncertainty for the tropical corals (e.g. Porites) can be reduced to ± 0.6 °C if a Li/Mg and Sr/Ca multi-regression approach is applied.

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