This project aims to improve understanding for the causal relationship between long-term changes of environmental factors elicited by climate change, i.e. temperature and ocean acidification, and organismal performance of an ecologically and economically highly important group of aquatic arthropods. Physiological, biochemical and molecular methods will be used to study how these environmental factors acutely and chronically affect molecular signalling mechanisms of hormonal regulation, growth, acid-base and ion regulation in various life stages of decapod crustacean species from temperate and subpolar latitudes. The life stages and species are expected to show differences in thermal tolerance and in their capacity for hormonal, acid-base and ion regulation, which would reflect differences in the sensitivities to climate change scenarios. This project explicitly addresses drivers of the EU Strategy for Marine and Maritime Research, the Life+ Programme and a major theme of the Cooperation Programme. It will be particularly useful in assessing and predicting vulnerabilities to the increasing environmental pressures on ocean ecosystems and biodiversity due to climate change. Training in molecular cell biology and endocrinology at Colorado State University, Fort Collins, USA and Bodega Marine Laboratory, UC Davis, USA will significantly foster the applicant’s career development and reintegration into the European Research Area at the Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany.