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Bacterial production measured by leucine and thymidine incorporation rates in French lakes

par Petit, M.;Servais, Pierre ;Lavandier, Pierre
Référence Freshwater biology, 42, 3, page (513-524)
Publication Publié, 1999

Article révisé par les pairs

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Résumé :

1. Production of heterotrophic bacterioplankton was estimated monthly by the tritiated thymidine and leucine incorporation methods during the draining and filling of the mesotrophic Lake Pareloup (over a 2.5-years sampling program). 2. Rates of 3H-leucine (leu) and 3H-thymidine (thy DNA) incorporation generally paralleled each other but the ratio of leu/thy DNA incorporation rates was higher for the draining period (34.5 mean) than during and after filling (11.5 mean). 3. After draining, the highest ratios were observed during periods of low temperature and low bacterial specific activity, while DNA labeling by 3H-thymidine was reduced. However, bacterial production estimates obtained by 3H-leucine (BPL) and 3H-thymidine (BPT) incorporation methods were generally well correlated and the average BPL/BPT ratio was equal to 0.78. 4. In addition, both methods were applied during a diel cycle in three lakes of different trophic status. An increase of leu/thy DNA incorporation rates was noted from the oligotrophic to the eutrophic system. In the absence of Cyanobacteria, BPL and BPT values were quite concordant on average. 5. In situations of unbalanced growth, BPL and BPT values can diverge but when considered over a sufficient period of time they were found to be in agreement.