Inter-Research
Aquatic Microbial Ecology

ABSTRACT: Batch cultures of natural bacterial assemblages from 3 lakes were used to measure bacterial growth efficiency (BGE) from increments in biomass and oxygen uptake. As could be expected from previous results and a logistic growth model, the growth efficiency varied among experiments and changed over time in relation to growth phases. During each experiment a maximum efficiency (range from 38 to 76%), which often coincided with maximum growth rate, could be identified. However, a significant relationship between efficiency and growth rate was not present and 2 cases of high efficiency during the apparent stationary phase were observed. Calculations of BGE by averaging procedures like linear regression of biomass increase and oxygen uptake versus time or end-point data at an apparent stationary phase most often resulted in low efficiency estimates. The maximum BGE values were on average 1.6 to 1.8 times higher than values calculated from regressions. We suggest to identify the maximum value in future measurements of BGE to avoid an underestimation of BGE. These findings are discussed in relation to in situ growth efficiency.

KEY WORDS: Lake water cultures · Bacterial growth efficiency

Published in AME Vol. 12, No. 2 (1997) on April 10
Print ISSN: 0948-3055; Online ISSN: 1616-1564. Copyright © Inter-Research, Oldendorf/Luhe, 1997