Life history traits of copepods in a changing Arctic : seasonal patterns in the physiology of Calanus glacialis

The Arctic experiences rapid environmental changes and to date, we cannot predict to what extent calanoid copepods can adapt to shifts in environmental conditions. On the Arctic shelf, the large species Calanus glacialis accumulates energy reserves in surface waters during the productive season and overwinters in diapause in deep waters. This thesis aims to investigate the physiology of C. glacialis in a comprehensive approach during activity and diapause in relation to environmental factors. This study revealed clear seasonal patterns in the physiology of C. glacialis. Enzymatic activities and extracellular pH (pHe) were high during the productive season, while catabolic activities were high and pHe low in winter. The usage of internal energy reserves was high in the end of overwintering. The timing of diapause is adjusted to the prevailing environmental conditions, which suggests that C. glacialis may be able to adjust to future climate driven changes in the environment.