Despite evidence for distribution shifts of single species and ecosystem changes as a reaction to climatic warming, little is known about direct implications of temperature changes on the role of physiology and adaptability for species distribution. In this study the effect of a short-term temperature increase on metabolic and lipid composition of liver tissue in the sub-Antarctic fish species Lepidonotothen squamifrons and the high-Antarctic species Trematomus hansoni were assessed using high-performance liquid chromatography and nuclear magnetic resonance spectroscopy. Data of this study seems to be the first data available for liver lipid composition of the two investigated species. Composition of succinate likewise phospholipid levels indicated temperature induced changes between 0 and 6 °C for T. hansoni and 2 and 9 °C for L. squamifrons. This complies well with observations of temperature dependent respiration, which indicated a rise in energy demand around 4 °C for the high- and sub-Antarctic species alike. Although changes in anaerobic metabolites found here were not significant, combination of results from this study and respiration experiments suggest that experimental temperature of 6 °C might be close to upper critical temperatures of T. hansoni, while L. squamifrons might be able to tolerate acute temperatures above 9 °C. Considering interspecies differences, higher total lipid and triacylglyceride levels support the suggestion of a higher degree of metabolic cold adaptation in high-Antarctic T. hansoni compared to sub-Antarctic L. squamifrons. The results of this study comply well with current ideas about temperature dependence of lipids and other metabolic compounds in fish. Recent suggestions about metabolic cold adaptation in Antarctic fish were confirmed and results indicated the existence of different degrees of cold adaptation in Antarctic fish, depending on variability of habitat temperature.
AWI Organizations > Biosciences > Integrative Ecophysiology