Award: PLR-1447291

The major aims of this proposal were to characterize the molecular and physiological response of closely related Antarctic fishes to predicted changes in ocean temperatures and chemistry. We used two main approaches to link physiological responses to the gene expression changes that represent the underlying mechanisms of these responses. Overall, we endeavored to identify commonalities among fish species that would provide greater understanding of the potential for adaptation to a changing environment among these unique fishes. Our research highlighted three major findings. 1) Despite being closely related, and more importantly, adapted to the same environmental conditions for millions of years, the physiological response of Notothenioid fish to changes in temperature and ocean pH are quite variable. In general, all three species studied displayed some level of stress response at the cellular level. This suggests the capacity to acclimate to new environmental conditions remains to some extent in these fish that are adapted to extreme cold, stable environments. The magnitude of this response as well as the duration of this response, however, varied significantly among the three species studied with Trematomus bernacchii displaying a robust stress response that persisted for several weeks, while Pagothenia borchgrevinki on the other hand, displayed a muted response with a very short duration. 2) The observed changes at the cellular level were all accompanied by increased metabolic rates, suggesting that there is at least a short-term energetic cost incurred by these fish when acclimating to different environments. These increased energetic costs likely come in the form of repairing extraneous cellular damage as well as disturbances to the acid base balance within specialized tissues such as the gill lamellae. 3) Trematomus bernacchii may show the greatest sensitivity to combined changes in ocean temperature and pH. Over a two-month acclimation period, this species showed a significant decline in body mass that was unrelated to food availability, suggesting long-term changes in ocean temperature and pH may have negative consequences at the population level for this species. In addition to the intellectual advances this project has provided, the broader impacts of these activities can be evidenced through the numerous training opportunities provided for students at multiple levels (High school, Undergraduate and Graduate students). Furthermore, participants under this project has engaged in activities to further public awareness of the importance of polar regions through numerous outreach activities with children's museums in both South Carolina and California, High Schools and public interest groups such as the Sierra Club. Last Modified: 06/07/2016 Submitted by: Sean P Place