Responses of autotrophic and heterotrophic rates of plankton from a subtropical coastal site to short-term temperature modulations

We investigated the responses of plankton collected throughout a seasonal cycle from a eutrophic, subtropical coastal site near Xiamen, China to short-term temperature modulations from the in situ ambient temperature. We used linear mixed effect models to estimate the tempera- ture coefficients (i.e. activation energy) and tested the hypothesis that the activation energies of autotrophic rates (i.e. phytoplankton growth and photosynthesis) are lower than those of heterotro- phic rates (i.e. microzooplankton grazing and community respiration). However, we found that there were no significant differences of activation energy (~0.65 eV) between autotrophic and het- erotrophic rates. Based on both physiological and statistical grounds, we argue that the inherent ac- tivation energies of phytoplankton photosynthesis and growth rates may not be lower than 0.65 eV in some instances.