Inter-Research
Aquatic Microbial Ecology

ABSTRACT: The effect of temperature on the incorporation of ³H-leucine (³H-Leu) and ³H-thymidine (³H-TdR) by bacterioplankton and bacterial isolates from marine, estuarine, and freshwater habitats was examined. There was a significant, positive correlation between in situ temperature and molar Leu:TdR incorporation by bacterioplankton in oceanic and lagoonal environments. Temperature manipulation experiments showed that Q₁₀ values for Leu incorporation by bacterial assemblages and isolates were significantly higher than corresponding Q₁₀ values for TdR incorporation. Evidence indicated that the temperature-dependence of Leu:TdR ratios was not a function of community composition, unbalanced growth, non-specific labelling of macromolecules, or substrate limitation. Thus, Leu and TdR incorporation appear to be affected by temperature differently. These experiments indicate that Leu and/or TdR conversion factors, for estimating bacterial production, are not constant with respect to temperature.

KEY WORDS: Temperature · Leucine · Thymidine · Bacterial production

Published in AME Vol. 11, No. 3 (1996) on December 31
Print ISSN: 0948-3055; Online ISSN: 1616-1564. Copyright © Inter-Research, Oldendorf/Luhe, 1996