TY - JOUR
T1 - Mg isotope fractionation in biogenic carbonates of deep-sea coral, benthic foraminifera, and hermatypic coral
AU - Yoshimura, Toshihiro
AU - Tanimizu, Masaharu
AU - Inoue, Mayuri
AU - Suzuki, Atsushi
AU - Iwasaki, Nozomu
AU - Kawahata, Hodaka
N1 - Funding Information:
Acknowledgements We express our appreciation to Dr. Tsuyoshi Ishikawa of JAMSTEC. We also thank Dr. Albert Galy of University of Cambridge for providing DSM-3, Dr. Jun Matsuoka and Dr. Kazuya Nagaishi of Marine Work Japan, Ms. Hiroko Hashizume of KCC, and Ms. Yumiko Yoshinaga of AIST; Dr. Hiroshi Amakawa for providing constructive comments and advice; Dr. Takashi Toyofuku for providing the benthic foraminifera specimens; Dr. Akira Iguchi for providing the branching coral specimens; and Hisaichi Kawaguchi, Takuji Osato, Noriyoshi Yoshimoto, Giorgio Bavestrello, Riccardo Cattaneo-Vietti, Yoshihiko Niiya, Hidekazu Muraoka, and the shipboard crews of R/V Hakurei-maru No. 2 for providing the deep-sea coral specimens. We thank two anonymous reviewers for thoughtful reviews and helpful comments. This work was performed with the support of Japan Society for the Promotion of Science (JSPS).
PY - 2011/11
Y1 - 2011/11
N2 - High-precision Mg isotope measurements by multiple collector inductively coupled plasma mass spectrometry were applied for determinations of magnesium isotopic fractionation of biogenic calcium carbonates from seawater with a rapid Mg purification technique. The mean δ 26Mg values of scleractinian corals, giant clam, benthic foraminifera, and calcite deep-sea corals were -0.87‰, -2.57‰, -2.34‰, and -2.43‰, suggesting preferential precipitation of light Mg isotopes to produce carbonate skeleton in biomineralization. Mg isotope fractionation in deep-sea coral, which has high Mg calcite skeleton, showed a clear temperature (T) dependence from 2.5 °C to 19.5 °C: 1,000 × ln(α) = -2.63 (±0.076) + 0.0138 (±0.0051) × T(R 2 = 0.82, p < 0.01). The δ 26Mg values of large benthic foraminifera, which are also composed of a high-Mg calcite skeleton, can be plotted on the same regression line as that for deep-sea coral. Since the precipitation rates of deep-sea coral and benthic foraminifera are several orders of magnitude different, the results suggest that kinetic isotope fractionation may not be a major controlling factor for high-Mg calcite. The Mg isotope fractionation factors and the slope of temperature dependence from deep-sea corals and benthic foraminifera are similar to that for an inorganically precipitated calcite speleothem. Taking into account element partitioning and the calcification rate of biogenic CaCO 3, the similarity among inorganic minerals, deep-sea corals, and benthic foraminiferas may indicate a strong mineralogical control on Mg isotope fractionation for high-Mg calcite. On the other hand, δ 26Mg in hermatypic corals composed of aragonite has been comparable with previous data on biogenic aragonite of coral, sclerosponges, and scaphopad, regardless of species differences of samples.
AB - High-precision Mg isotope measurements by multiple collector inductively coupled plasma mass spectrometry were applied for determinations of magnesium isotopic fractionation of biogenic calcium carbonates from seawater with a rapid Mg purification technique. The mean δ 26Mg values of scleractinian corals, giant clam, benthic foraminifera, and calcite deep-sea corals were -0.87‰, -2.57‰, -2.34‰, and -2.43‰, suggesting preferential precipitation of light Mg isotopes to produce carbonate skeleton in biomineralization. Mg isotope fractionation in deep-sea coral, which has high Mg calcite skeleton, showed a clear temperature (T) dependence from 2.5 °C to 19.5 °C: 1,000 × ln(α) = -2.63 (±0.076) + 0.0138 (±0.0051) × T(R 2 = 0.82, p < 0.01). The δ 26Mg values of large benthic foraminifera, which are also composed of a high-Mg calcite skeleton, can be plotted on the same regression line as that for deep-sea coral. Since the precipitation rates of deep-sea coral and benthic foraminifera are several orders of magnitude different, the results suggest that kinetic isotope fractionation may not be a major controlling factor for high-Mg calcite. The Mg isotope fractionation factors and the slope of temperature dependence from deep-sea corals and benthic foraminifera are similar to that for an inorganically precipitated calcite speleothem. Taking into account element partitioning and the calcification rate of biogenic CaCO 3, the similarity among inorganic minerals, deep-sea corals, and benthic foraminiferas may indicate a strong mineralogical control on Mg isotope fractionation for high-Mg calcite. On the other hand, δ 26Mg in hermatypic corals composed of aragonite has been comparable with previous data on biogenic aragonite of coral, sclerosponges, and scaphopad, regardless of species differences of samples.
KW - Biomineralization
KW - MC-ICP-MS
KW - Magnesium
KW - Stable isotope
KW - Vital effect
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U2 - 10.1007/s00216-011-5264-0
DO - 10.1007/s00216-011-5264-0
M3 - Article
C2 - 21805065
AN - SCOPUS:81855221789
VL - 401
SP - 2755
EP - 2769
JO - Fresenius Zeitschrift fur Analytische Chemie
JF - Fresenius Zeitschrift fur Analytische Chemie
SN - 0016-1152
IS - 9
ER -