Ecology of Heterotrophic Microflagellates. II. Bioenergetics and Growth

Abstract

The bioenergetics of growth of 6 species of heterotrophic (bacterivorous) microflagellates was studied in batch cultures. Maximum growth rates varied between 0.15 and 0.25 h-' among the species, but growth as slow as 0.028 h-' could be maintained. Yield (gross growth efficiency) was found to be ca. 30 % (volume) or, in 2 cases, 34 and 43 % (C basis) respectively; net growth efficiency (C) was 60 %. Respiratory and growth rates were directly proportional to consumption rate within the range of growth rates studied. Clearance (volume of water cleared for bacteria per unit time and measured in fractions of cell volume) ranged from about 5 X 104 to about 106 h-'; this large variation can in part be explained as a consequence of specialization to different food particle slzes. In general, the parameter values suggest that the type of flagellates studied may grow on and possibly control the concentration of bacteria found in marine plankton.