Increased seawater temperatures cause temporal shifts in catabolic pathways of Antarctic krill Euphausia superba

Antarctic krill (Euphausia superba) hold a central position in the Southern Ocean food web, yet little is known about how they might respond to anthropogenic climate change, in particular the projected rise of temperature in their habitat. Krill‘s life cycle and metabolism are timed closely to their highly seasonal environment. An elevation in sea water temperature has the potential to desynchronize krill physiology with essential cornerstones in the course of the year. The aim of this study was to elucidate the direct effects of rising sea water temperatures on Antarctic krill catabolism. To this end, krill were exposed to gradually increasing temperatures from 0.5°C to 7°C over a period of four months. Analysis of morphometry, respiration, elemental composition and activity of four key enzymes suggest an earlier onset of protein catabolism and an extended period of lipid oxidation to meet increased energy demands. These temporal shifts may interfere with the buildup of essential energy reserves for winter during the highly productive summer season