Meeting Abstract

21.5  Saturday, Jan. 4 14:30  Energy trade-offs and cellular damage: The physiological response of the Antarctic fish Trematomus bernacchii to global climate change ENZOR, L.A.*; PLACE, S.P.; University of South Carolina; University of South Carolina enzorl@email.sc.edu

Studies have projected future changes in sea surface temperature and pCO₂ levels will impact higher latitudes to a greater extent than temperate regions. For notothenioid fishes of the Southern Ocean, evolution in extremely stable, cold waters have resulted in several adaptations which have left these fishes more susceptible to oxidative stress, and poorly prepared for global climate change. We have analyzed the metabolic and cellular response of Trematomus bernacchii to a long-term, multi-stressor scenario relevant to the predicted changes in the Southern Ocean. By combining whole animal respirometry with cellular level analysis of energy allocation, osmoregulatory mechanisms and cellular damage, we aimed to determine if acclimation to increased sea surface temperature (4°C), increased seawater pCO₂ levels (1000 µatm), or a combination of these two parameters result in energetic trade-offs and exacerbated cellular damage. Our data suggest a synergistic relationship exists between elevated temperature and pCO₂, as the combination of these variables further elevates metabolic rates and delays the acclimatory response. Overall, long-term acclimation to experimental treatments resulted in an increased capacity for acid base regulation as well as moderate increases in antioxidant capacity. In response to the added energetic demands of these pathways, T. bernacchii also displayed a significant increase in metabolic capacity. However, our data indicate this increase in capacity is insufficient to fully compensate for the added energetic demands of environmental change and that cellular homeostasis is ultimately achieved through energy trade-offs.