An investigation into mechanical strength of exoskeleton of hydrothermal vent shrimp (Rimicaris exoculata) and shallow water shrimp (Pandalus platyceros) at elevated temperatures

• Shrimp species Pandalus platyceros and Rimicaris exoculata exoskeletons are analyzed.
• Temperature dependent properties of shrimp exoskeleton are compared.
• Mechanical properties are correlated with structure and composition of exoskeleton.
• Mechanical properties reduce with increase in temperature.
• Presence of biominerals gives better thermal stability to structure.

This investigation reports a comparison of the exoskeleton mechanical strength of deep sea shrimp species Rimicaris exoculata and shallow water shrimp species Pandalus platyceros at temperatures ranging from 25 °C to 80 °C using nanoindentation experiments. Scanning Electron Microscopy (SEM) observations suggest that both shrimp exoskeletons have the Bouligand structure. Differences in the structural arrangement and chemical composition of both shrimps are highlighted by SEM and EDX (Energy Dispersive X-ray) analyses. The variation in the elastic moduli with temperature is found to be correlated with the measured compositional differences. The reduced modulus of R. exoculata is 8.26 ± 0.89 GPa at 25 °C that reduces to 7.61 ± 0.65 GPa at 80 °C. The corresponding decrease in the reduced modulus of P. platyceros is from 27.38 ± 2.3 GPa at 25 °C to 24.58 ± 1.71 GPa at 80 °C. The decrease in reduced moduli as a function of temperature is found to be dependent on the extent of calcium based minerals in exoskeleton of both types of shrimp exoskeletons.