Meeting Abstract
P2.31 Saturday, Jan. 5 Effects of repeated heat stress and recovery on thermal tolerance of the fingered limpet, Lottia digitalis PASPARAKIS, C.*; BJELDE, B.E.; TODGHAM, A.E.; San Francisco State University ; San Francisco State University ; San Francisco State University cpas@mail.sfsu.edu
The ability of a species to respond to both increases in mean temperature as well as the increased frequency of extreme high temperature exposures will affect its survival in a changing environment. The rocky intertidal zone is among one of the most highly variable environments on Earth, with rapidly shifting conditions dependent on the tidal cycle. Therefore, intertidal organisms must be able to tolerate extreme and stochastic changes in temperature on a daily basis. Although there have been numerous studies investigating the thermal physiology of intertidal animals, few have focused on an organism’s physiological capacity to withstand repeated heat stress and how previous exposure to sublethal heat stress may shift an organism’s upper temperature tolerance. Lottia digitalis, a species of limpet ubiquitous along the coast of California in the upper middle intertidal zone, were collected from Fort Ross California in early June 2012 and brought back to the lab to acclimate to ambient ocean conditions for two weeks. To investigate the effect of a preliminary mild heat shock of differing magnitudes on upper thermal tolerance, limpets were aerially exposed to 15°, 25° and 30°C on Day 1. The following day, in sync with the start of the midday low tide period, electrodes were placed into the limpets to record heart rate as temperatures were increased at a rate of 6°C/h to 48°C, a severe, lethal heat shock. Previous exposure to a mild thermal stress had no effect on the upper temperature tolerance of limpets as determined by a break in cardiac function. Next steps include examining Hsp70 protein levels following the preliminary mild heat shock and repeating this experiment using higher preliminary heat stress temperatures.
