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Effects of Calcium, Strontium, and Magnesium on the Coccolithophorid Cricosphaera (Hymenomonas) carterae. I. Calcification
Marine Biology
  • Patricia Blackwelder, University of South Carolina - Columbia
  • R. E. Weiss, Duke University
  • K. M. Wilbur, Duke University
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The present investigation concerns the effects of calcium, strontium, and magnesium on calcification and mineralogy of the calcified bodies (coccoliths) of the coccolithophorid Cricosphaera (Hymenomonas) carterae. The capacity of cells to calcify in various concentrations of these ions was examined following preliminary decalcification in CO2. At a concentration of 10-2 M Ca, 75% of the cells formed coccoliths within 24 h and almost all cells were recalcified after 2 days. At 10-3 or 10-4 M Ca no recalcification occurred. However, with the addition of Sr to the Ca-deficient media, calcification took place as shown by observations of coccoliths and by analysis of Ca. The percentage of calcified cells increased with increasing concentrations of Sr. Strontium added to a Ca-deficient media was much more effective than an equivalent concentration of Ca. No Sr was deposited in the coccoliths. X-ray analysis demonstrated that calcite was deposited by cells in all concentrations of Ca and Sr at which calcification took place. At concentrations of Mg in the media from 0.0 to 4.2×10-2 M, the cells retained their ability to calcify, although calcification was markedly reduced in the absence of Mg. In low Mg concentrations (1.3×10-4 and 4.2×10-6 M), the coccoliths were 60% calcite and 40% aragonite, and in the absence of Mg, only calcite was formed.

©Springer-Verlag 1976

Additional Comments
U.S. Public Health Service Research grant #: DE-O1382-O6
Citation Information
Patricia Blackwelder, R. E. Weiss and K. M. Wilbur. "Effects of Calcium, Strontium, and Magnesium on the Coccolithophorid Cricosphaera (Hymenomonas) carterae. I. Calcification" Marine Biology Vol. 34 Iss. 1 (1976) p. 11 - 16 ISSN: 0025-3162
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