. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. l°°l 3 ppm Sr ^^ 8 ppm Sr H NSW E%1 80 ppm Sr 144 192 ance of the shell cap and statolith granules. Total calcium was not observed to increase in animals from the basal medium until 144 h, without evidence of mineralization. Profiles representing total strontium concentration of whole embryos paralleled those for calcium but were proportional to medium levels (Fig. 2B). Total magnesium concentration of whole embryo de- creased during embryogenesis and this decline was atten- uated in the absence of strontium (Fig. 2C). Altho
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. l°°l 3 ppm Sr ^^ 8 ppm Sr H NSW E%1 80 ppm Sr 144 192 ance of the shell cap and statolith granules. Total calcium was not observed to increase in animals from the basal medium until 144 h, without evidence of mineralization. Profiles representing total strontium concentration of whole embryos paralleled those for calcium but were proportional to medium levels (Fig. 2B). Total magnesium concentration of whole embryo de- creased during embryogenesis and this decline was atten- uated in the absence of strontium (Fig. 2C). Although small, the decrease in whole embryo magnesium concen- tration over time from the 0 ppm Sr treatment was sig- nificant (P< ). Comparison of the strontium distribution coefficients (¥^r) over time indicated that the discriminatory mecha- nism for this element was not acquired until after the critical window. Ksr (Fig. 3A) for all treatments contain- ing strontium had values close to one before the onset of mineralization, ( ± , mean ± , combined means of all treatments containing strontium, 24-96 h, n = 12). An abrupt decrease in the values of K^ ( ± , mean ± , n = 4) was observed at 120 h as mineralization began. The distribution coefficient for synthetic aragonite prepared from artificial seawater is approximately at room temperature (Kinsman, 1969). The values of the magnesium distribution coefficient, KMg, for the 0 ppm Sr treatment ranged from + at 24 h to ± at 192 h (mean ± , n = 5 and 6, respectively) indicating discrimination of this element (Fig. 3B). This may represent the biochemical compo- nent of the regulatory mechanism for total magnesium because shell formation was absent. ^ C CRITICAL WINDOW FOR Sr h- H 3 24 48 M 0 ppm Sr F°l 3 ppm Sr ^§ 8 ppm Sr H NSW El BOppmSr 80 96 120 HOURS FROM OVIPOSITION. Figure 2. Chemical analysis of whole embryos plus egg strand. (A) Total calcium; a small but s
Size: 1239px × 2016px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
