Physiological adaptations of copepods from the North Sea and the North Atlantic to changing nutritional conditions

Abstract

Marine calanoid copepods, which constitute a major component of the marine food web, have to adapt to changing environmental conditions in order to efficiently use dietary components for growth and reproduction. Detailed knowledge on their feeding behaviour, their physiological responses to nutritional conditions, i.e. digestive and metabolic activities, and their functional responses, i.e. reproduction, is of major importance in order to better understand how diet affects growth and reproduction of copepods. The present thesis aims at elucidating physiological adaptations of calanoid copepod species to changing nutritional conditions and how these are related to different life cycle strategies, metabolic requirements and biochemical properties. For this purpose, species with different life strategies from the North Sea, i.e. Temora longicornis, Acartia clausi and Centropages typicus, and the St. Lawrence estuary, i.e. Calanus finmarchicus and Metridia longa, were investigated during several phytoplankton blooms. A comprehensive data set on digestive, metabolic and functional responses to changing nutritional conditions is presented and the data are discussed with respect to different life strategies.