Temperature-dependence of planktonic metabolism in the Subtropical North Atlantic Ocean

Abstract. The temperature dependence of planktonic metabolism in the Subtropical North Atlantic Ocean was assessed on the basis of measurements of gross primary production (GPP), community respiration (CR) and net community production (NCP), as well as experimental assessments of the response of CR to temperature manipulations. Metabolic rates were measured at 68 stations along three consecutive longitudinal transects completed during the Malaspina 2010 Expedition, in three different seasons. Temperatures gradients were observed in depth and at basin and seasonal scale. The results showed seasonal variability in the metabolic rates, being the highest rates observed during the spring transect. The overall mean integrated GPP/CR ratio was of 1.39 ± 0.27 decreasing from winter to summer and the NCP for the Subtropical North Atlantic Ocean during this cruises, was net autotrophy (NCP > 0) in about two-thirds of the total sampled communities (68.2%). Here, we reported the activation energies describing the temperature-dependence of planktonic community metabolism, which generally was higher for CR than for GPP in the Subtropical North Atlantic Ocean, as the metabolic theory of ecology predicts. Also, we performed an assessment of the activation energies describing the responses to in situ temperature at field (EaCR = 1.64 ± 0.36 eV) and those derive experimentally by temperature manipulations (EaCR = 1.45 ± 0.6 eV), which showed a great consistency.