Carbon and nitrogen budget of the calanoid copepod Temora stylifera: effect of concentration and composition of food

Abstract

The energy budget of Temora stylifera Dana, measured in C and N units, was determined for 2 phytoplanktonic diets and a range of concentrations. Excretion and respiration rates were strongly influenced by the type of food or its concentration after the second day. No maxima of rates of respiration or ingestion were achieved within the experimental range; maxima of faecal pellets and egg production were obtained at higher concentrations. Equations were developed to describe the pattern of response of each term of the budget to variations of food concentration. The difference between ingestion and expenses, 'G' , was also evaluated for various concentrations; it did not seem to increase when food was in excess. Reasons for imbalance of the equation are discussed. The differential nutritive value could be attributed to differences in the 2 algal diets; although Phaedoactylurn tricornuturn seemed inadequate for good survival and reproduction of T. stylifera, Hymenomonas elongata covered all nutritonal needs at low cell concentrations.