Life history traits of copepods in a changing Arctic (RiS ID 6168)

Zooplankton communities of northern higher latitudes are dominated by large calanoid copepods of the genus Calanus spp. They are well adapted to the environment in which they live, making them indicators of factors that influence the health and productivi ty of marine ecosystems. Calanus spp. are considered to endure times of unfavorable environmental conditions in a state of arrested development, referred to as diapause. During diapause they rely on internal energy reserves, i.e. wax esters stored in larg e oil sacs, accumulated during the productive summer season. However, to date we have very limited knowledge regarding the overwintering physiology and adaptability of Calanus spp. to environmental changes. Although enzyme activity and gene expression can act as proxies for the physiological processes they drive, their temporal changes in polar copepods are yet to be clarified. Therefore, this study aims to track seasonal changes in enzyme activity, hemolymph pH and ion concentration, lipid and protein co ntent and gene expression patterns in C. glacialis, a key species in Arctic shelf seas. Its physiological mechanisms during diapause shall be elucidated in Svalbard waters over one year with a special emphasis on the polar night. Alongside the field study , the physiological response and overwintering success of critical copepod life stages to changes in temperature, food and light regime will be assessed in incubation experiments in the laboratory.