Analysis of Shell Color Distribution and Metallic Elements of Shells in Surf Clam(Mactra veneriformis)
To explore the color distribution and metallic elements contents characteristics in Mactra veneriformis,this experiment fo-cused on the purple and white shell populations of Mactra veneriformis in the Dagang and Dongjiang Port areas in Tianjin.We ana-lyzed the coloring distribution characteristics and the contents of four metallic elements in prismatic layer and nacreous layer of shells from purple and white color in surf clam(Mactra veneriformis)by stereomicroscope observation and atomic absorption spectrophotome-try(AAS).The shell color of the inner side of purple groups appeared deeper than the outer side,and the main part of the color was distributed at the junction of the prismatic layer with the horny layer and the prismatic layer with the nacreous layer.The Na and K contents in purple groups were obviously higher than those in white groups in both shell layers,Dagang area.The content of Mg in purple groups was significantly higher than those in white groups in both shell layers in both two areas.In conclusion,the color distri-bution in Mactra veneriformis was at the junction of the shell layer,and the element of Mg might be related to the formation of the purple shell of the four cornered clam.