Meeting Abstract
Climate change models predict increases in the frequency and intensity of extreme weather events. The fitness consequences to many organisms will be determined by their capacity to adjust their thermal sensitivities and the associated energetic costs. Our study was designed to determine how thermal defense strategy (constitutive versus induced) and the intensity of an acute high temperature challenge might affect post-stress physiological performance of limpets on rocky shores. The limpets Lottia scabra and L. austrodigitalis are typically found living together in the high intertidal zone, but may adopt different strategies for dealing with thermal stress. L. scabra exhibits high constitutive levels of the stress protein Hsp70 but no additional induced synthesis at high temperatures, whereas L. austrodigitalis exhibits low levels of constitutive Hsp70 and high inducibility. We measured respiration rate for field-collected and lab-acclimated individuals of each species under benign conditions in the lab, before and after exposure to one of five peak temperatures (14, 24, 28, 32, or 36 °C) during a 4.5-hour simulated low tide. Unlike L. scabra, L. austrodigitalis exhibited a significant increase in oxygen consumption following aerial exposure to high temperature, consistent with activation of the heat shock response. We expect ongoing analyses to show a positive correlation between individual respiration rate and Hsp70 expression level in our experimental limpets.
