Through their physiological processes, mesozooplankton can contribute significantly to the marine biogeochemical cycling of carbon and nitrogen. However some of these processes have been poorly parameterised in ecosystem models. Respiration in particular has been measured in terms of basal respiration which is related to temperature but independent of other metabolic activities such as feeding. This project will investigate the response of copepod physiology to food quality and temperature. A range of food quality (phytoplankton N:P ratio) will be achieved through sampling a latitudinal transect in the Atlantic Ocean (Atlantic Meridional Transect cruise, October 2010), a coastal time series station 20 km south of Plymouth, UK (spring, summer, autumn, winter sampling 2010-2011), and maintaining continuous cultures of selected species of phytoplankton under N and P limitation. Copepod (Calanus spp. and Oithona spp.) feeding rate, egg production, excretion and respiration rate will be determined across this range of food quality. The influence of temperature on copepod respiration rate will be determined using a temperature gradient block and planar optodes. This physiological data will be placed in the context of the Continuous Plankton Recorder (CPR) Survey's 80 year dataset of the ecology and biogeography of plankton in the North Atlantic, and contribute to the Dynamic Green Ocean Model Project to better parameterise the PlankTOM10 model. This poster will give an overview of the project before focusing on the results of coastal copepod feeding experiments undertaken in preparation for the AMT cruise.