Altering the balance between bacterial production and protistan bacterivory triggers shifts in freshwater bacterial community composition
Simek, K.; Nedoma, J.; Pernthaler, J.; Posch, T.; Dolan, J.R. (2002). Altering the balance between bacterial production and protistan bacterivory triggers shifts in freshwater bacterial community composition. Antonie van Leeuwenhoek 81(1-4): 453-463 In: Antonie van Leeuwenhoek. Stichting Antonie van Leeuwenhoek: Amsterdam. ISSN 0003-6072; e-ISSN 1572-9699, more |   |
| Authors | | Top | - Simek, K.
- Nedoma, J.
- Pernthaler, J.
| - Posch, T.
- Dolan, J.R., more
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| Abstract | Bacterivorous protists are known to induce changes in bacterial community composition (BCC). We hypothesizedthat changes in BCC could be related quantitatively to a measure of grazing: the ratio of bacterial mortality togrowth rate. To test this hypothesis, we analyzed time-course changes in BCC, protistan grazing rate, and bacterialproduction from 3 in situ studies conducted in a freshwater reservoir and three laboratory studies. In the fieldexperiments, samples were manipulated to yield different levels of protistan bacterivory and incubated in dialysisbags. Laboratory investigations were continuous cultivation studies in which different bacterivorous protists wereadded to bacterial communities. BCC was assessed using 4-6 different rRNA-targeted oligonucleotide probes forcommunity analysis. Change in BCC was estimated as the sum of changes in the proportions of the twophylogenetic groups that showed the largest shifts. Analysis of a set of 22 estimates of shifts in the ratio of grazingto production rate over periods of 48-72 h and BCC showed that BCC was positively and tightly correlated(r2 = 0.784) with shifts in the ratio of grazing mortality to cell production. While the nature of a shift in BCC isunpredictable, the magnitude of the change can be related to changes in the balance between bacterial productionand protistan grazing. |
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