Life cycle strategies of planktic copepods in the high-Arctic Kongsfjord/ Spitsbergen with special reference to their overwintering strategies (diapause)

The life cycle strategies of small dominant calanoid (Pseudocalanus minutus and P. acuspes) and cyclopoid (Oithona similis) copepods will be investigated in a high-Arctic fjord on Svalbard. Vertical zooplankton samples will be taken continuously in the Kongsfjord close to Ny-Ålesund over a one-year period. Experiments with live specimens (egg production, nauplii hatching) and first physiological measurements (respiration) will be carried out in Longyearbyen at UNIS. Zooplankton samples will be analysed in terms of species abundance, stage and sex composition. Gonad maturation will be determined via morphological characteristics. Histological, biochemical and physiological investigations (food spectrum, gut epithel, lipid content and composition, respiration, level of ecdysteroid hormones) are supposed to characterize the activity and reproductive state of the species. These results will also allow to draw conclusions about their overwintering strategies (e.g. diapause). In addition, sediment samples will be examined for diapause stages (eggs, cysts).