EAPS

Title: A metabolic constraint on the biogeography of marine species

Abstract: Oxygen played a key role in the evolution of marine ecosystems. However, oxygen has not generally been considered a major constraint on the contemporary biogeography of species outside regions of exceptionally low O2. I will present a combination of physiological, climate, and species distribution data, to argue that the limits of several diverse species ranges are governed by the ratio of oxygen supply and demand, even in the well-oxygenated Atlantic Ocean. These limits correspond to an energetic requirement for organismal activity of about 2-5 times that at rest, a ratio that is shared by most terrestrial species. This metabolic constraint is rapidly tightened in the presence of climate warming due to the combination of warmer water and less O2. I will use Earth System Models to investigate and compare the loss of aerobically viable habitat in two periods of interest – the climate change projected for the 21st century and the end-Permian mass extinction.