Ref ID : 982
David Glaser; Simultaneous consumption of bacteria and dissolved organic matter by Tetrahymena pyriformis. Microbial Ecology 15:189-201, 1988
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The addition of ciliated protozoa to aquatic microcosms and bench-scale sewage treatment plants increase decomposition rates. This is surprising, in as much as protozoa consume bacteria, which are the primary decomposers. One possible mechanism of the increase in decomposition rate is the direct consumption of dissolved organic matter by protozoa that are feeding primarily on bacteria. This possibility was explored experimentally in two-stage continuous cultures, with glucose limiting Escherichia coli in the first stage and E. coli limiting Tetrahymena pyriformis in the second. Glycine and histidine were the test nutrients. The results of adding them to the second stages suggested that direct uptake by ciliates does not affect the dynamics of dissolved amino acids in pelagic environments or activated sludge plants. Ciliates might, however, affect the dynamics of amino acid pools in environments high in nutrients and ciliates, perhaps including some microenvironments near decomposing material of in benthic sediments. Direct uptake of dissolved amino acids by ciliates probably does not affect ciliate or bacterial populations substantially.