Meeting Abstract
Understanding thermal ranges and limitations of organisms becomes important in light of climate change and observed effects on ecosystems as reported by the IPCC (Pörtner et al., IPCC 2014). This understanding also supports efforts to project climate-induced shifts in the distribution and productivity of marine species. For animals, the integrative concept of oxygen and capacity limited thermal tolerance (OCLTT) has successfully characterized the earliest thermal limits to performance and the consequences of such limits at ecosystem level. Steady state temperature dependent performance profiles trace the thermal window and indicate a key role for aerobic metabolism and energy budget in shaping the temperature dependence of steady state performances, from growth to exercise and reproduction. Recent modeling illustrates how routine energy demand characterizes the limits of the realized niche. Evolutionary adaptation is presently unable to keep animals in place; they rather follow the moving isotherms. Assessments across climate zones require consideration of how OCLTT principles were modulated on evolutionary timescales, e.g. in the tropics, in subpolar areas characterized by temperature variability and in permanently cold polar waters. Earlier work has proposed how these relationships have shaped the functional characteristics of survivors in mass extinction events during earth history (Pörtner et al., 2005, J. Geophys. Res., 110, C09S10) and contributed to the evolution of endothermy in mammals and birds (Pörtner, 2004, Physiol. Biochem. Zool. 77, 959-981, Clarke and Pörtner, 2010, Biol. Rev. 85, 703–727). It will be discussed how the knowledge of physiological principles can play a role in reducing uncertainty about projected impacts of climate variability and change.
