Review of immediate cardiac response in intertidal gastropods limpets at varying temperature, salinity and air exposure

Abstract

In 1990 Depledge and Andresen developed a #eld/laboratory, non-invasive technique to monitor the immediate response of cardiac activity in bivalves. Since then, several researchers have experienced and tested the variability of heart beat rate (HBR)and of associated metabolic rates under di$erent conditions in intertidal molluscs. Review of HBR immediate response in acute exposure and acclimation to changes of salinity, thermal stressors and air exposure were examined to test di$erent hypothesis. In intertidal Mediterranean and tropical limpets, the decrease in metabolic rate with a decrease in salinity was di$erent in animals experiencing di$erent degrees of salinity !uctuation in their respective microhabitats. Intertidal limpets respond to temperature increases, increasing HBR and metabolic rate. Furthermore, when reaching the highest temperature experienced in #eld, HBR shows extreme responses as secondary bradicardia. Finally, when exposed to dry/saturated air cycles, lower shore intertidal limpets show regular alternation of normal HBR and acardia, whilst the upper shore limpet showed transient acardia only during exposure to dry air. In conclusion, it was demonstrated that di$erent patterns of immediate HBR responses couple di$erent !uctuations of the physical environment experienced by individuals inhabiting di$erent levels of the shore.