Effect of temperature on "Paracartia grani nauplii" growth rates estimated through direct and indirect methods

Abstract

Activity of the enzymes aminoacyl-tRNA synthetases (AARS) and weight-specific growth rates of naupliar stages of the planktonic marine copepod Paracartia grani were measured at different temperatures (12 to 28 ºC) in the laboratory, in order to assess the effect of temperature on both somatic growth and protein synthesis rates. A secondary aim consisted on the validation of the AARS method (Yebra and Hernández-León, 2004) as index of in situ growth rate for the naupliar stages. The nauplii were reared feeding on saturating concentrations of either the autotrophic algae Rhodomonas baltica or the heterotrophic dinoflagellate Oxyrrhis marina. Measurements of length growth rate and enzymatic activity were compared at the different temperatures. Temperature significantly affected somatic growth and AARS activities (r2=0.95-0.99, p<0.001). Specific AARS activity showed a highly significant correlation (r2=0.96, p<0.001) with the direct measurement of growth rates in the laboratory.