7.3.1 Bacteria
The major bacterial taxa present in high mountain Pyrenean lakes are characteristic
of the plankton present in worldwide freshwater environments and different from
the oceans (Fig. 7.3, data from Barberán and Casamayor 2010). Bacteroidetes,
Betaproteobacteria and Actinobacteria are the predominant groups in high-altitude
lakes, with a significantly higher proportion of Betaproteobacteria and a lower
proportion of Alphaproteobacteria than in lowland freshwaters (Barberán and
Casamayor 2010). Also, the lakes’ ecosystems can be synoptically sorted according
to the evolutionary history contained in the whole bacterial assemblages without the
0
0
500
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1500
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2500
Number of OTUs
Bacteria
0
0.5
1.0
1.5
2.0
2.5
200
400
600
800
Archaea
Number of sequences (*10 )
5
1 0
15
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25
30
35
Archaea
0
0
500
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2500
10
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10
3
OTU Rank
Abundance
10
4
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Bacteria
Archaea
0
Fig. 7.2 Rank abundance (top) and rarefaction curves (bottom) for bacterial and archaeal OTUs
inhabiting three connected shallow Pyrenean lakes communities within the Aigüestortes i Estany
de Sant Maurici National Park. From Vila-Costa et al. (2013) with kind permission from Oxford
University Press
164
E.O. Casamayor