. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 10 R. GILES ET AL Table I Concentrations o\f inorganic ions in the filtered natural seawater Ion Concentration (mA/) ± standard dev. Na+ 463 -i- 2 K+ ± Mg2+ Ca2+ ± ± Sr+ ± HCO3~ + CO32~ or total carbonate ± 2-fold higher in extrapallial fluid. Therefore, only car- bonate ion was added to natural seawater to create the growth solutions. A comparison of the values of ion concentrations determined for seawater and extrapallial fluid is included in Figure 5. The samples of nacre were g
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 10 R. GILES ET AL Table I Concentrations o\f inorganic ions in the filtered natural seawater Ion Concentration (mA/) ± standard dev. Na+ 463 -i- 2 K+ ± Mg2+ Ca2+ ± ± Sr+ ± HCO3~ + CO32~ or total carbonate ± 2-fold higher in extrapallial fluid. Therefore, only car- bonate ion was added to natural seawater to create the growth solutions. A comparison of the values of ion concentrations determined for seawater and extrapallial fluid is included in Figure 5. The samples of nacre were glued to a stainless steel disk with epikot resin and placed in the fluid cell of a com- mercial AFM (Nanoscope III from Digital Instruments, Santa Barbara, CA 93103). Samples were always oriented with the proximal side (the side facing the animal during life) exposed for imaging. After an appropriate area had been selected by imaging in air, growth solution was added to the fluid cell. The sample was examined for signs of growth for 15-20 min under a steady gravity flow of this solution. Typical flow rates were 5 n\/s, which corresponds to a replacement of the fluid cell volume every few sec- onds. The tip was then withdrawn and flow stopped for h to allow more time for growth to occur. Only the exit line was blocked so that the cell remained in chemical contact with at least 40 ml of the solution in a reservoir above the cell. The sample was then examined again under flow for signs of growth. The procedure was repeated with an alternate growth solution; either the pH was raised while maintaining the same carbonate concentration, or vice versa. After growth had occurred with a given solu- tion, only one or two more solutions could be tried with a given sample before the surface became so rough that further growth could not be analyzed. All growth exper- iments were conducted at about 20°C. Results Figure 1 shows an AFM image of the nacreous surface. Most of one polyg
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
