Previous Article | Next Article ![]()
Applied and Environmental Microbiology, November 1998, p. 4299-4306, Vol. 64, No. 11
Max-Planck-Institut für marine
Mikrobiologie, D-28359 Bremen, Germany,1 and
Institut für Zoologie und Limnologie, University of
Innsbruck, Innsbruck, Austria2
Received 13 May 1998/Accepted 2 September 1998
The seasonal variations in community structure and cell morphology
of pelagic procaryotes from a high mountain lake (Gossenköllesee, Austria) were studied by in situ hybridization with rRNA-targeted fluorescently labeled oligonucleotide probes (FISH) and
image-analyzed microscopy. Compositional changes and biomass
fluctuations within the assemblage were observed both in summer and
beneath the winter ice cover and are discussed in the context of
physicochemical and biotic parameters. Proteobacteria of the beta
subclass (beta-proteobacteria) formed a dominant fraction of
the bacterioplankton (annual mean, 24% of the total counts), whereas
alpha-proteobacteria were of similar relative importance only during
spring (mean, 11%). Bacteria of the
Cytophaga-Flavobacterium cluster, although less abundant, constituted the largest fraction of the filamentous morphotypes during
most of the year, thus contributing significantly to the total
microbial biomass. Successive peaks of threadlike and rod-shaped archaea were observed during autumn thermal mixing and the period of
ice cover formation, respectively. A set of oligonucleotide probes
targeted to single phylotypes was constructed from 16S rRNA-encoding
gene clone sequences. Three distinct populations of uncultivated
microbes, affiliated with the alpha- and beta-proteobacteria, were
subsequently monitored by FISH. About one-quarter of all of the
beta-proteobacteria (range, 6 to 53%) could be assigned to only two
phylotypes. The bacterial populations studied were annually recurrent,
seasonally variable, and vertically stratified, except during
the periods of lake overturn. Their variability clearly exceeded the
fluctuations of the total microbial assemblage, suggesting that the apparent stability of total bacterioplankton abundances may mask highly dynamic community fluctuations.
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Seasonal Community and Population Dynamics of
Pelagic Bacteria and Archaea in a High Mountain Lake
*
Corresponding author. Mailing address: Max Planck
Institute for Marine Microbiology, Celsiusstr. 1, D-28359 Bremen,
Germany. Phone: 49 421 2028 940. Fax: 49 421 2028.580. E-mail: jperntha{at}mpi-bremen.de.
This article has been cited by other articles:
| J. Bacteriol. | Microbiol. Mol. Biol. Rev. | Eukaryot. Cell | All ASM Journals |
|---|