Study of taphonomic attributes and major mechanical properties of molluscan shells from chilika lake, Odisha, India

Abstract

It is the natural selection over millions of years, which make mollusc shells to develop their unique shell structure and mechanical properties to protect themselves from attack by predators. The mechanical function of shell depends upon its ability to resist deformation and failure under imposed environmental stresses. The shell is predominantly made up of CaCO3. The effect of shell microstructure, bonding strength of calcite crystals and intercalations with organic portion,on overall mechanical behaviour is significant towards its adaptation with time. These were contemplated and investigated by researchers in recent past but still the understanding is modest. In the present investigation an attempt has been made to study the variation of mechanical characteristics of predominant bivalve shells collected from the Eastern fringe of Chilika Lake, Odisha, India, namely Anadara granosa, Meretrix meretrix and Sunetta meroe. Different taphonomic attributes like abrasion, fragmentation, bioerosion and dissolution along with disparity of mechanical properties were studied. Variations of Spatial thickness and density of shells were estimated and correlated with specific ecological niches. Investigations regarding the same shows interesting trends and correlations from a taphonomic study and with tested mechanical behaviours. This study may be related to the causes for unique behaviour of molluscs and possible functional significance of the shell structures.