Calcium isotope fractionation in calcite and aragonite

Gussone, Nikolaus; Böhm, Florian; Eisenhauer, Anton; Dietzel, Martin; Heuser, Alexander; Teichert, Barbara M.A.; Reitner, Joachim; Wörheide, Gert; Dullo, Wolf‐Christian

doi:10.1016/j.gca.2005.06.003

Cited by 256 publications

(176 citation statements)

References 40 publications

(73 reference statements)

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“…We therefore propose that brachiopod samples are a reliable archive for the reconstruction of δ 88/86 Sr values of past seawater. This conforms with recent observations from cold water corals (Raddatz et al, 2013) but differs from earlier studies for warm water corals that suggested a temperature-dependent isotope fractionation in carbonates (Fietzke and Eisenhauer, 2006), implying a potential species-dependent biomineralization process analogous to that for Ca isotopes (Farkaš et al, 2007a;Gussone et al, 2005;Nägler et al, 2000).…”

Section: Sr Fractionation Factor (δ 88/86 Sr Cc-sw ) Between the Carbsupporting

confidence: 87%

The Phanerozoic δ88/86Sr record of seawater: New constraints on past changes in oceanic carbonate fluxes

Vollstaedt

Eisenhauer

Wallmann

et al. 2014

Geochimica et Cosmochimica Acta

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107

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The isotopic composition of Phanerozoic marine sediments provides important information about changes in seawater chemistry. In particular, the radiogenic strontium isotope ( 87 Sr/ 86 Sr) system is a powerful tool for constraining plate tectonic processes and their influence on atmospheric CO 2 concentrations. However, the 87 Sr/ 86 Sr isotope ratio of seawater is not sensitive to temporal changes in the marine strontium (Sr) output flux, which is primarily controlled by the burial of calcium carbonate (CaCO 3 ) at the ocean floor. The Sr budget of the Phanerozoic ocean, including the associated changes in the amount of CaCO 3 burial, is therefore only poorly constrained. Here, we present the first stable isotope record of Sr for Phanerozoic skeletal carbonates, and by inference for Phanerozoic seawater (δ 88/86 Sr sw ), which we find to be sensitive to imbalances in the Sr input and output fluxes. This δ 88/86 Sr sw record varies from ~0.25‰ to ~0.60‰ (vs. SRM987) with a mean of ~0.37‰. The fractionation factor between modern seawater and skeletal The oceanic net carbonate flux of Sr (F(Sr) carb ) varied between an output of -4.7x10 10 mol/Myr and an input of +2.3x10 10 mol/Myr with a mean of -1.6x10 10 mol/Myr.On time scales in excess of 100Myrs the F(Sr) carb is proposed to have been controlled by the relative importance of calcium carbonate precipitates during the "aragonite" and "calcite" sea episodes. On time scales less than 20Myrs the F(Sr) carb seems to be controlled by variable combinations of carbonate burial rate, shelf carbonate weathering and recrystallization, ocean acidification, and ocean anoxia. In particular, the Permian/Triassic transition is marked by a prominent positive δ 88/86 Sr sw -peak that reflects a significantly enhanced burial flux of Sr and carbonate, likely driven by bacterial sulfate reduction (BSR) and the related alkalinity production in deeper anoxic waters. We also argue that the residence time of Sr in the Phanerozoic ocean ranged from ~1Myrs to ~20Myrs.

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Section: Sr Fractionation Factor (δ 88/86 Sr Cc-sw ) Between the Carbsupporting

confidence: 87%

The Phanerozoic δ88/86Sr record of seawater: New constraints on past changes in oceanic carbonate fluxes

Vollstaedt

Eisenhauer

Wallmann

et al. 2014

Geochimica et Cosmochimica Acta

Self Cite

107

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“…3 indicates that a potential temperature correlation of T. septentrionalis would not extend to published whole-shell data from other species , supporting species-specific processes. As opposed to the species measured by Gussone et al (2005), and many other two-layered brachiopod shells, G. vitreus secretes an additional thick tertiary prismatic layer. Maybe this physiological difference results in a heavier δ 44/40 Ca species-specific isotopic composition of G. vitreus.…”

Section: Calcium Isotopesmentioning

confidence: 57%

“…Brachiopod data from Gussone et al (2005) suggest a weak δ 44/40 Ca-temperature dependence of about 0.015‰/°C. Apparently G. vitreus does not reflect temperature in its calcium isotopes when compared to the brachiopod temperature gradient of Gussone et al (2005). However, the δ 18 Otemperature calculations of G. vitreus agree with on-site measured seawater temperatures.…”

Section: Calcium Isotopesmentioning

confidence: 97%

“…Fig. 3 shows this study's isotopic data and brachiopod data from Gussone et al (2005) plotted against temperature. All depicted brachiopods consist of a low Mg calcite shell.…”

Section: Calcium Isotopesmentioning

confidence: 99%

“…Maybe this physiological difference results in a heavier δ 44/40 Ca species-specific isotopic composition of G. vitreus. Thecidellina sp., the brachiopod species that is mainly responsible for the 0.015‰ temperature gradient derived from the Gussone et al (2005) data, also has a specific shell structure. It is composed predominantly of primary layer calcite (Williams, 1973).…”

Section: Calcium Isotopesmentioning

confidence: 99%

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Stable isotope profiles (Ca, O, C) through modern brachiopod shells of T. septentrionalis and G. vitreus: Implications for calcium isotope paleo-ocean chemistry

et al. 2010

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Brachiopod shells are widely used as an archive to reconstruct elemental and isotopic composition of seawater. Studies, focused on oxygen and carbon isotopes over the last decades, are increasingly extending to the emerging calcium isotope system. To date, only little attention has been paid to test the reliability of fossil brachiopods on their modern counterparts. In this context, the present study investigates two modern brachiopods, Terebratulina septentrionalis (eastern Canada, 5-30 m depth, 7.1°C seasonal temperature variation, two-layer shell) and Gryphus vitreus (northern Mediterranean, 200 m depth, constant all-year round temperature, three-layer shell). Both species were sampled along the ontogenetic growth direction and calcium, oxygen, and carbon isotopes as well as elemental concentration were measured. Calcium isotopes were analyzed on TIMS. The elemental composition was analyzed by LA-ICP-MS and ICP-AES. The results indicate an intra-specimen δ 44/40 Ca variation ranging from 0.16 to 0.33‰, pointing to a fairly homogenous distribution of calcium isotopes in brachiopod shells. However, in the light of the suggested 0.7‰ increase in calcium isotopes over the Phanerozoic such intra-specimen variations constrain ocean reconstruction. δ 44/40 Ca values of T. septentrionalis do not seem to be affected by growth rate. Calcium isotopic values of G. vitreus are heavy in the central part of the shell and trend towards lighter values in peripheral areas approaching the maximum isotopic composition of T. septentrionalis. The maximum interspecies δ 44/40 Ca difference of 0.62‰ between T. septentrionalis and G. vitreus indicates that care should be taken when using different taxa, species with different strontium content or brachiopods with specialized shell structure, such as G. vitreus, for ocean water reconstruction in terms of Ca isotopic composition. T. septentrionalis may record Ca isotopic fractionation related to seasonal seawater temperature variations in its shell but this is difficult to resolve at the current analytical precision. Average δ 18 O-derived temperatures of the two investigated species are close to on-site measured temperatures.

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Calcium and calcium isotope changes during carbon cycle perturbations at the end-Permian

Komar

Zeebe

2016

Paleoceanography

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Negative carbon and calcium isotope excursions, as well as climate shifts, took place during the most severe mass extinction event in Earth's history, the end-Permian (∼252 Ma). Investigating the connection between carbon and calcium cycles during transient carbon cycle perturbation events, such as the end-Permian, may help resolve the intricacies between the coupled calcium-carbon cycles, as well as provide a tool for constraining the causes of mass extinction. Here we identify the deficiencies of a simplified calcium model employed in several previous studies, and we demonstrate the importance of a fully coupled carbon cycle model when investigating the dynamics of carbon and calcium cycling. Simulations with a modified version of the Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir model, which includes a fully coupled carbon-calcium cycle, indicate that increased weathering rates and ocean acidification (potentially caused by Siberian Trap volcanism) are not capable of producing trends observed in the record, as previously claimed. Our model results suggest that combined effects of carbon input via Siberian Trap volcanism (12,000 Pg C), the cessation of biological carbon export, and variable calcium isotope fractionation (due to a change in the seawater carbonate ion concentration) represents a more plausible scenario. This scenario successfully reconciles 13 C and 44 Ca trends observed in the sediment record, as well as the proposed warming of >6 ∘ C.

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Calcium isotope fractionation in calcite and aragonite

Cited by 256 publications

References 40 publications

The Phanerozoic δ88/86Sr record of seawater: New constraints on past changes in oceanic carbonate fluxes

The Phanerozoic δ88/86Sr record of seawater: New constraints on past changes in oceanic carbonate fluxes

Stable isotope profiles (Ca, O, C) through modern brachiopod shells of T. septentrionalis and G. vitreus: Implications for calcium isotope paleo-ocean chemistry

Calcium and calcium isotope changes during carbon cycle perturbations at the end-Permian

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