Meeting Abstract
P2.27 Saturday, Jan. 5 PHYSIOLOGICAL RESPONSES OF THE PORCELAIN CRAB PETROLISTHES CINCTIPES TO SIMULTANEOUS EXPOSURE TO INCREASED VARIABILITY OF pCO2, TEMPERATURE AND EMERSION PAGANINI, A.W.*; STILLMAN, J.H.; San Francisco State University; Univ. of California, Berkeley paganini@mail.sfsu.edu
Organisms that inhabit the intertidal zone experience large daily fluctuations in temperature, immersion and pH, and those fluctuations are expected to increase along the California coast under future climate scenarios. How intertidal invertebrates will respond to increased environmental variability of multiple abiotic factors is largely unknown. We investigated performance of the Porcelain crab, Petrolisthes cinctipes, under conditions of present and future variation in temperature, increased pCO2 (low pH), and emersion. Adult P. cinctipes were exposed to three levels of simulated low tide exposure during the day: 11°C emersion, 25 or 30°C emersion, or 11°C under immersion as a control. At night the crabs in each treatment were exposed to either low (7.6, 7.15) or ambient (8.1) pH. Following two weeks of acclimation, we measured respiration rates at 11 and 18°C and upper thermal limits of cardiac performance (typically reported as the critical thermal maximum or CTmax). When constantly immersed, metabolic rates were higher in crabs experiencing low pH (40 ± 2.1 µmol O2 h-1g-1) than crabs that experienced ambient pH. Metabolic depression was observed in crabs that experienced aerial daily heat spikes when compared to crabs that had no heat stress during acclimatization, yet showed no differences between pH treatments. When crabs experienced no thermal, aerial, or pH stress they exhibited the highest CTmax (32.8 ± 0.4 ºC) indicating that any single or combined stressor in our experiments lowered the critical thermal maximum temperature that P. cinctipes can withstand under these conditions.
