Meeting Abstract

P3.109  Friday, Jan. 6  Impact of ocean acidification on development and energetics of porcelain crab early life history stages CARTER, H.A.*; CEBALLOS, L.; MILLER, N.; STILLMAN, J.H.; San Francisco State University hacarter@sfsu.edu

Oceans are acidifying as a consequence of absorbing elevated levels of atmospheric CO₂. Results of ocean acidification (OA) studies in crustaceans are conflicting and few assess impacts on coastal intertidal organism and their early life stages. Adult porcelain crabs of genus Petrolisthes are common intertidal inhabitants and have a complex life cycle. Little is known about the physiological mechanisms allowing larvae to transition from a stable CO₂ environment (open ocean) to a habitat with daily and seasonal CO₂ fluctuations (intertidal). When during development does CO₂ tolerance occur? Do larvae hatch with physiological mechanisms to compensate for decreases in pH? Are life stages differentially affected by CO₂, and if so, which are most vulnerable? In this study, embryos, larvae and juvenile P. cinctipes were reared under two pH levels (ambient pH~8.0, and low pH~7.6), achieved by bubbling seawater with pure CO₂ gas. Oxygen consumption rate, total protein, dry weight, lipid consumption rate and survival were determined at each developmental stage. Results suggest significant maternal effects among a sample of 13 broods, with high variability among individuals in response to OA. However, when reared in low pH, embryonic metabolism was 5% lower, while larvae and juveniles displayed a trend of higher metabolic rates compared to control (7% and 29% respectively). Furthermore, embryo lipid consumption rates were 40% lower in individuals reared in acidified water. Alternatively, no significant differences were observed in larval dry weight or survival of larvae and juveniles. Results thus far indicate certain stages of P. cinctipes compensate for high CO₂, but potential tolerance may differ between female broods. Studying responses to OA at different stages will give us a better understanding of physiological mechanisms allowing organisms to persist in an acidifying ocean.