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

• YUYAMA, Ikuko

• Higuchi, Tomihiko

• Shirai, Kotaro

• Mezaki, Takuma

Abstract

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 CaCO3 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.

Journal

• Geology

  Geology 45 (12), 1087-1090, 2017-10

  Geological Society of America

Keywords

• Geology

Details

• CRID: 1050283688375598720
• NII Article ID: 120007127785
• NII Book ID: AA00656697
• ISSN: 00917613
• DOI: 10.1130/g39516.1
• HANDLE: 2241/00159836
• Web Site: https://tsukuba.repo.nii.ac.jp/records/54414
• Web Site: http://pubs.geoscienceworld.org/geology/gsa/geology/article-pdf/45/12/1087/3979068/1087.pdf
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • Crossref
  • CiNii Articles
  • KAKEN