Diapositive 1 - de l'Université libre de Bruxelles

Chapitre IIFigure 19: Mg/Ca ratio in the skeleton of Paracentrotus lividus grown in aquarium according totemperature and salinity (♦ 36 psu and ■ 39 psu ) and in field specimens (×); equation of the nonlinear model and 95 % confidence interval (lower: Mg/Ca = 0.116 – e - 0.254T ;upper: Mg/Ca = 0.122 - e - 0.287T ). The model was calculated using data obtained at both salinities,this factor having no significant effect on Mg/Ca ratio (see Table 9).Sr/Ca ratio. The skeletal Sr/Ca ratio was dependent on temperature (according to anegative quadratic relation) (Figure 20), growth rate (positive linear relation) (Figure 21)and salinity (negative linear relation), but not on seawater Sr/Ca (stepwise multipleregression in Table 9). Temperature and growth rate explained each ca 20% of thevariability and salinity a further 9%. The Sr/Ca ratios of the adult specimens grown in thefield at a mean annual temperature of 17.65 °C were significantly different from those ofthe juveniles grown in aquarium at a close temperature (p Mann Withney