In 1990 Depledge and Andresen developed a #eld/laboratory, non-invasive techniqueto 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$erent conditions in intertidal molluscs.Review of HBR immediate response in acute exposure and acclimation to changesof salinity, thermal stressors and air exposure were examined to test di$erent hypothesis.In intertidal Mediterranean and tropical limpets, the decrease in metabolic rate witha decrease in salinity was di$erent in animals experiencing di$erent degrees of salinity!uctuation in their respective microhabitats. Intertidal limpets respond to temperatureincreases, increasing HBR and metabolic rate. Furthermore, when reaching the highesttemperature experienced in #eld, HBR shows extreme responses as secondary bradicardia.Finally, when exposed to dry/saturated air cycles, lower shore intertidal limpetsshow regular alternation of normal HBR and acardia, whilst the upper shore limpetshowed transient acardia only during exposure to dry air. In conclusion, it was demonstratedthat di$erent patterns of immediate HBR responses couple di$erent !uctuationsof the physical environment experienced by individuals inhabiting di$erent levelsof the shore.
|Number of pages||1|
|Publication status||Published - 2009|