Ontogenetic trends of mineralogy and elements in the shell of abalone, Haliotis discus hannai ino

摘要

Japanese abalone, Haliotis discus hannai; with shell lengths 8, 14, 25, and 55 mm were used-for mineralogy and element composition studies. Besides calcite and aragonite, dolomite (CaMg(CO_3)_2) was detected for the first time in abalone shells. No calcite was detected in the 8-mm shells. The percentage of calcite increased steadily from 1.6 percent to 13.6 percent in shells from 14 to 55 mm, while that of aragonite decreased from 95.3 percent to 83.9 percent. Dolomite varied from 2.5 percent to 9.0percent. The level of Mg, Mn, Fe, Na, and Al in 8 to 55 mm shells increased, whereas those of Zn and Cu declined. Possible reasons for these trends are discussed.