Molecular and morphological diversity of
prokaryotic communities in the pelagic
photic zone of lakes along an
eutrophication gradient in lakes
(Mazurian Lake District, Poland)
Ryszard J. Chróst, Adriana Mazurkiewicz
& Tomasz Adamczewski
Microbial Ecology Department, University of Warsaw
Miecznikowa 1, 02-096 Warsaw, Poland; [email protected]
10th Symposium on Aquatic Microbial Ecology, Faro (Portugal), 2007
Microbial diversity
Environmental resources
(organic matter and nutrients)
concentration and availability
and trophic interactions
Bacterial community composition,
cellular metabolic acitivity, growth
and biomass production rates
Major aim of the studies
•  Morphological and phylogenetic diversity of
prokaryotic communities in lakes along the
trophic status
Methods
•  epifluorescence microscopy and digital image analysis system
•  rDNA PCR
•  Denaturing Gradient Gel Electrophoresis (DGGE)
Study site
Mazurian Lake District
Warsaw
Mikołajki
Mikołajki – field laboratory
Trophic State Index (TSI) of the studied lakes
65
55
50
45
40
hypereutrophic
60
oligo/mesotrophic
Trophic state index
70
eutrophic
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Bacterial production & metabolically active cells
A. Bacterial production was positively proportional to the trophic state index of
the studied lakes
B. Percentage of the metabolically active bacteria decreased along the trophic
gradient of the studied lakes
Size distribution of bacterial cells
Percent contribution of small 0.2 - 0.5 µm cells decreased along the
trophic gradient of the studied lakes
rDNA - PCR - DGGE Phylogenotypes
Total numer of prokaryotic phylogenotypes in the photic layer of the
studied lakes decreased along their trophic gradient during summer
stratification period
α– and β–Proteobacteria
A. There was no relationship between percentage of α-Proteobacteria
phylogenotypes and the trophic state index of the studied lakes.
B. Percentage of β-Proteobacteria phylogenotypes was positively
proportional to the trophic gradient of lakes.
Cytophaga-Flavobacterium and
Cyanobacteria
A. Percentage of Cytophaga-Flavobacterium phylogenotypes decreased
along the trophic gradient of lakes.
B. There was no relationship between percentage of cyanobacterial
phylogenotypes and the trophic state index of the studied lakes.
rDNA - PCR - DGGE analysis of bacteria
Phylogenetic composition of prokaryotic communities
depended on the trophic status of the studied lakes
Conclusions
rDNA-PCR-DGGE analysis of prokaryotic communities
has shown that phylogenetic diversity of
microorganisms depended strongly on the trophic status
of the studied lakes
The contribution of Cytophaga-Flavobacterium and βProteobacteria to the total eubacterial phylogenotypes
strongly correlated with the trophic status of the studied
lakes
Prokaryotic communities living in lakes of the similar
trophic conditions displayed characteristic diversity of
microbial phylogenotypes
Thanks for your attention