Several experiments have been performed on three congeneric species of the calanoid copepod Acartia to determine the effects of small-scale turbulence on metabolic rates. Both inorganic nitrogen and phosphorus excretion rates significantly increased ∼60% under turbulent (shaker) versus non-turbulent (standing) conditions. These results agree with previous indirect evidence in laboratory microcosms and could be mediated by an increment in the frequency of escape reactions by turbulent motion mechanical stimulation.