Meeting Abstract

26.3  Friday, Jan. 4  Ocean acidification impairs olfaction and elevates respiration in deep sea hermit crabs, with high variation between individuals KIM, TW*; TAYLOR, J; LOVERA, C; BARRY, JP; Monterey Bay Aquarium Research Institue ktwon@mbari.org

Future ocean pH is projected to drop considerably at all depths as surface water continues to absorb rising levels of atmospheric CO₂; the pH at bathyal depths (200-2000 m) is expected to be lowered by 0.2-0.4 units by the end of this century. Still the ability of organisms to adapt to lower pH has been far less explored in deep water species than shallow water species. To test the effect of environmental acidification on deep-sea animals, we compared behavioral and physiological features of the deep-sea (~900 m) hermit crab Pagurus tanneri between pH 7.6 (ambient control) and pH 7.1 (low-pH experimental) lab conditions. No significant difference was detected between treatments for some parameters, such as oxygen consumption and the “boldness” of crabs, measured as time spent in shell after attack by a potential predator (octopus). At lower pH, however, hermit crabs decreased their rates of antennular flicking (the equivalent of “sniffing”) and also tended to have a slower speed of prey detection, indicating that lower pH can impair olfactory function. Respiration rates transiently increased in response to higher CO₂ level at 4 weeks after treatments but returned at 9 weeks. Furthermore, hermit crabs at lower pH showed higher individual variation in antennular flicking rates, prey detection speeds, and respiration rates. This pattern suggests that, although ocean acidification impairs some abilities linked to survival, the ability of P. tanneri to cope with lower pH appears to vary considerably among individuals, potentially promoting population survival by natural selection.