pH and dissolution of crystalline style in some bivalve molluscs of Porto Novo coastal waters
A comparative study of the pH of crystalline style, digestive diverticula and stomach fluid in six bivalve species,Anadara rhombea, Crassostrea madrasensis, Meretrix meretrix, M. casta, Katelysia opima andDonax cuneatus revealed that the digestive diverticula are more acidic while crystalline style is either slightly acidic or nearly neutral. The significance of this finding is discussed. In vitro dissolution of crystalline style of all the six species in buffer solutions of varying pH from 3·6 to 9·0 was observed and the study indicated that the optimum pH for style dissolution is around 8·0 in all species exceptingDonax cuneatus where some dissolution was recorded only at pH 9·0. Based on the physical changes observed in the style, a mechanism of style dissolution has been put forward.