diversity can be obtained by comparison of both traditional and molecular
technologies.
In a preliminary study of 11 selected high mountain Pyrenean lakes, the
microeukaryotes major taxa found belonged to 9 high-rank taxonomic groups and
26 eukaryal classes. Predominant groups, both in abundance and in occurrence,
were Chrysophyceae, Cryptophyta, uncultured Alveolata, pennate diatoms of the
class Fragilariophyceae, Chlorophyceae, Dinophyceae and Fungi of the
Chytridiomycota clade among others (Triadó-Margarit and Casamayor 2012) with
most of the OTUs found exclusively affiliated to clusters formed by uncultured
microorganisms. The genetic diversity within the Cryptophyta and Chlorophyceae
was low and these groups also have the highest relatedness to cultured species.
Cryptophyta contained the OTUs with the highest ubiquity in the dataset, but in
general, most of the microeukaryote OTUs (>75% of them) were found at only one
lake, highlighting the high potential of the whole Pyrenean lacustrine district to
contain a high number of new microeukaryotes taxa. Overall, this study and a recent
study in the Alps and Himalayan mountains (Kammerlander et al. 2015) unveiled
the high mountain lakes habitat as an important biodiversity reservoir of genetically
rich Stramenopiles (mostly Chrysophyceae), Alveolata (Ciliophora) and
Opisthokonta (Fungi). A comparison with the community composition of marine
and freshwater molecular samples (Fig. 7.11) shows the consistent dominance of
Chrysophyceae in high-altitude lakes and Artic lakes (Charvet et al. 2012). Overall,
Chrysophyceae were more widely distributed in lakes with high oligotrophic
conditions. Trophic status modulates the changes in freshwater eukaryote community composition, and eutrophic lakes are less species-rich. Perturbation such as
higher availability of reactive nitrogen introduced by atmospheric deposition may
also change the community structure of the most sensible species (Kammerlander
et al. 2015). Thus, preserving the cold and (ultra)oligotrophic characteristics of the
high mountain lakes environment may be of great interest for the study of the
ecology and evolution of such idiosyncratic protists but, again, field experimentation should be carried out to confirm these findings.
In fact, the genetic novelty level after a GenBank database search (TriadóMargarit and Casamayor 2012) showed that many of the 18S rRNA gene sequences
recovered in the Pyrenean survey were below the species-level cut-off most widely
accepted for microeukaryotes (i.e. 98% identity, Caron et al. 2009). Mostly in the
case of Rhizaria-Cercomonads, a set of small (about 10 lm) free-living heterotrophic flagellates difficult to identify under the microscope for species identity, for
which c. 90% of the sequences would be new species, and StramenopilesChrysophyceae with 30–40% of the sequences potentially as new species.
Conversely, Pyrenean Cryptophyta and Chlorophyceae showed very low genetic
novelty (<3% and <5% of new species, respectively). Other taxa with substantial
novelty were found within the Opisthokonta (Fungi). Fungi have been invoked as a
target group to develop a microbial perspective on conservation biology because
both it is important by itself and the fact that fungi biodiversity and their ecosystems
roles can benefit conservation in general (Griffith 2012; Heilmann-Clausen et al.
2015).
7 Towards a Microbial Conservation Perspective …
173
technologies.
In a preliminary study of 11 selected high mountain Pyrenean lakes, the
microeukaryotes major taxa found belonged to 9 high-rank taxonomic groups and
26 eukaryal classes. Predominant groups, both in abundance and in occurrence,
were Chrysophyceae, Cryptophyta, uncultured Alveolata, pennate diatoms of the
class Fragilariophyceae, Chlorophyceae, Dinophyceae and Fungi of the
Chytridiomycota clade among others (Triadó-Margarit and Casamayor 2012) with
most of the OTUs found exclusively affiliated to clusters formed by uncultured
microorganisms. The genetic diversity within the Cryptophyta and Chlorophyceae
was low and these groups also have the highest relatedness to cultured species.
Cryptophyta contained the OTUs with the highest ubiquity in the dataset, but in
general, most of the microeukaryote OTUs (>75% of them) were found at only one
lake, highlighting the high potential of the whole Pyrenean lacustrine district to
contain a high number of new microeukaryotes taxa. Overall, this study and a recent
study in the Alps and Himalayan mountains (Kammerlander et al. 2015) unveiled
the high mountain lakes habitat as an important biodiversity reservoir of genetically
rich Stramenopiles (mostly Chrysophyceae), Alveolata (Ciliophora) and
Opisthokonta (Fungi). A comparison with the community composition of marine
and freshwater molecular samples (Fig. 7.11) shows the consistent dominance of
Chrysophyceae in high-altitude lakes and Artic lakes (Charvet et al. 2012). Overall,
Chrysophyceae were more widely distributed in lakes with high oligotrophic
conditions. Trophic status modulates the changes in freshwater eukaryote community composition, and eutrophic lakes are less species-rich. Perturbation such as
higher availability of reactive nitrogen introduced by atmospheric deposition may
also change the community structure of the most sensible species (Kammerlander
et al. 2015). Thus, preserving the cold and (ultra)oligotrophic characteristics of the
high mountain lakes environment may be of great interest for the study of the
ecology and evolution of such idiosyncratic protists but, again, field experimentation should be carried out to confirm these findings.
In fact, the genetic novelty level after a GenBank database search (TriadóMargarit and Casamayor 2012) showed that many of the 18S rRNA gene sequences
recovered in the Pyrenean survey were below the species-level cut-off most widely
accepted for microeukaryotes (i.e. 98% identity, Caron et al. 2009). Mostly in the
case of Rhizaria-Cercomonads, a set of small (about 10 lm) free-living heterotrophic flagellates difficult to identify under the microscope for species identity, for
which c. 90% of the sequences would be new species, and StramenopilesChrysophyceae with 30–40% of the sequences potentially as new species.
Conversely, Pyrenean Cryptophyta and Chlorophyceae showed very low genetic
novelty (<3% and <5% of new species, respectively). Other taxa with substantial
novelty were found within the Opisthokonta (Fungi). Fungi have been invoked as a
target group to develop a microbial perspective on conservation biology because
both it is important by itself and the fact that fungi biodiversity and their ecosystems
roles can benefit conservation in general (Griffith 2012; Heilmann-Clausen et al.
2015).
7 Towards a Microbial Conservation Perspective …
173