Magnetic separation of calcite and aragonite for use in radioactive carbon analysis

Hang, Tran Thuy; Kato, Kazuhiro; Wada, Hideki

doi:10.2343/geochemj.2.0289

Cited by 4 publications

(6 citation statements)

References 11 publications

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“…Calcite intensity was much stronger than that of aragonite, the specific peak of the latter (<10 wt%) being almost equivalent to the background (as described in Higuchi et al, 2017). The presence of aragonite was therefore confirmed by Meigen’s stain at 85 °C for 10 min (Hang, Kato & Wada, 2014).…”

Section: Methodsmentioning

confidence: 99%

Differential gene expression in skeletal organic matrix proteins of scleractinian corals associated with mixed aragonite/calcite skeletons under low mMg/Ca conditions

Yuyama

Higuchi

2019

PeerJ

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Although coral skeletons generally comprise aragonite crystals, changes in the molar Mg/Ca ratio (mMg/Ca) in seawater result in the incorporation of calcite crystals. The formation mechanism of aragonite and calcite crystals in the scleractinian coral Acropora tenuis was therefore investigated by RNA-seq analysis, using early growth stage calcite (mMg/Ca = 0.5) and aragonite (mMg/Ca = 5.2)-based corals. As a result, 1,287 genes were up-regulated and 748 down-regulated in calcite-based corals. In particular, sixty-eight skeletogenesis-related genes, such as ectin, galaxin, and skeletal aspartic acid-rich protein, were detected as up-regulated, and six genes, such as uncharacterized skeletal organic matrix protein 5, down-regulated, in low-Mg/Ca conditions. Since the number of down-regulated genes associated with the skeletal organic matrix of aragonite skeletons was much lower than that of up-regulated genes, it is thought that corals actively initiate construction of an aragonite skeleton by the skeletal organic matrix in low-Mg/Ca conditions. In addition, different types of skeletal organic matrix proteins, extracellular matrix proteins and calcium ion binding proteins appeared to change their expression in both calcite-formed and normal corals, suggesting that the composition of these proteins could be a key factor in the selective formation of aragonite or calcite CaCO3.

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Section: Methodsmentioning

confidence: 99%

Differential gene expression in skeletal organic matrix proteins of scleractinian corals associated with mixed aragonite/calcite skeletons under low mMg/Ca conditions

Yuyama

Higuchi

2019

PeerJ

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“…DR1 in the GSA Data Repository 1 ). To confirm the presence of aragonite, Meigen's stain using 10% cobalt nitrate was conducted at 85 °C for 10 min (Hang et al, 2014).…”

Section: Determination Of Crystal Structurementioning

confidence: 99%

Temperature dependence of aragonite and calcite skeleton formation by a scleractinian coral in low mMg/Ca seawater

Higuchi

Shirai

Mezaki

et al. 2017

Geology

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Temperature-dependent aragonite and calcite formation by scleractinian corals were examined in low molar (m) Mg/Ca seawater, the experimental conditions replicating the fluctuating mMg/Ca levels prevailing throughout the Phanerozoic Eon. Incubation and skeletal growth monitoring of juveniles of the scleractinian coral Acropora solitaryensis for 4 months from the planula stage, in seawater with mMg/Ca ratios of 5.2, 1.0, and 0.5, and temperatures of 19-28 °C, indicated that polymorphism of present-day scleractinian corals in low mMg/Ca seawater is also influenced by seawater temperature. However, corals produced more aragonite than formed in inorganic CaCO 3 precipitation experiments under the same conditions, except at 19 °C. Although the aragonite content reflected the results of the latter (abiotic) experiments at 19 °C, it is suggested that aragonitic scleractinian corals controlled skeletal formation biologically under low mMg/Ca conditions at higher temperature, growth rates being faster at 25 °C and slower at 19 °C for all mMg/Ca ratios. Compared with growth rates under the present-day-equivalent seawater Mg/Ca level of 5.2, juvenile growth decreased by 62.8% ± 14.7% and 56.7% ± 6.7% under mMg/Ca levels of 1.0 and 0.5, respectively; the results suggest that growth of aragonitic scleractinian corals is suppressed throughout varying seasonal temperatures under low mMg/ Ca conditions. This supports previous findings from variable temperature perspectives that scleractinian corals grow more slowly in low mMg/Ca (Cretaceous) seawater, interpreted as a possible explanation for the hiatus in scleractinian reef building in the Cretaceous Period.

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“…Polymorph separation for radiocarbon dating applications has been attempted by a few groups, 12,13 but our work is the rst attempt to explore electrophoretic properties as a means of nondestructive calcite-aragonite separation.…”

Section: Archaeological Implicationsmentioning

confidence: 99%

“…4,5 Because CaCO 3 samples have a high carbon content, they are attractive for radiocarbon dating. [6][7][8][9][10][11][12][13] However, since each phase could be formed at different timesand by physical processes with different archaeological implicationsit is appealing to be able to date each polymorph separately. For this reason, there are strong incentives to develop non-destructive strategies to separate CaCO 3 polymorphs in a way that is thorough and efficient.…”

Section: Introductionmentioning

confidence: 99%

“…Separation of the stained particles required either manual selection 14 or a magnetic eld. 13 Another strategy for separating particles is based on electrophoresis. When particles are dispersed in aqueous media, their surfaces become charged, and the net surface charge density determines the extent to which the particles can be moved in the presence of electric elds.…”

Section: Introductionmentioning

confidence: 99%

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Assessing the feasibility of electrophoretic separation of CaCO₃polymorphs for archaeological applications

Walsh

Poduska

2017

Anal. Methods

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Magnetic separation of calcite and aragonite for use in radioactive carbon analysis

Cited by 4 publications

References 11 publications

Differential gene expression in skeletal organic matrix proteins of scleractinian corals associated with mixed aragonite/calcite skeletons under low mMg/Ca conditions

Differential gene expression in skeletal organic matrix proteins of scleractinian corals associated with mixed aragonite/calcite skeletons under low mMg/Ca conditions

Temperature dependence of aragonite and calcite skeleton formation by a scleractinian coral in low mMg/Ca seawater

Assessing the feasibility of electrophoretic separation of CaCO₃polymorphs for archaeological applications

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Magnetic separation of calcite and aragonite for use in radioactive carbon analysis

Cited by 4 publications

References 11 publications

Differential gene expression in skeletal organic matrix proteins of scleractinian corals associated with mixed aragonite/calcite skeletons under low mMg/Ca conditions

Differential gene expression in skeletal organic matrix proteins of scleractinian corals associated with mixed aragonite/calcite skeletons under low mMg/Ca conditions

Temperature dependence of aragonite and calcite skeleton formation by a scleractinian coral in low mMg/Ca seawater

Assessing the feasibility of electrophoretic separation of CaCO3polymorphs for archaeological applications

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Assessing the feasibility of electrophoretic separation of CaCO₃polymorphs for archaeological applications