Microbial biodiversity in saline shallow lakes of the Monegros Desert, Spain

Abstract

The Monegros Desert contains one of the largest sets of inland saline lakes in Europe constituting a threatened landscape of great scientific and ecological value with large number of reported endemisms. We analyzed bacteria, archaea, and microbial eukaryotes from 11 saline lakes in winter and spring by rRNA gene fingerprinting and sequencing covering large salinity (2.7-22.1%) and temperature ranges (1.5-35.3 °C). The highest ecological diversity (Shannon-Weaver index) was found in protists and the lowest in Archaea. Eukaryotes showed higher ecological diversity at intermediate salinities, whereas Bacteria and Archaea did not. The genetic diversity was broad and with remarkable novelty. The highest novelty was found in Archaea at the lowest saline concentrations, whereas for bacteria and protists, no differences were observed along the gradient. Euryarchaeota of the enigmatic group DHVEG-6 and phylotypes distantly related to well-known haloarchaea were present in several sites. Recurrent presence of bacterial phylotypes distantly related to Psychroflexus and Cryomorphaceae initially isolated from polar marine habitats was observed. Saline lakes contained chlorophyta, among other new groups, substantially different from green algae previously reported in marine or freshwater. The great scientific and ecological value found for macroorganisms can be extended to the idiosyncratic microorganisms inhabiting such unique habitat in Europe.

High occurrence of Pacearchaeota and Woesearchaeota (Archaea superphylum DPANN) in the surface waters of oligotrophic high‐altitude lakes

“…Pacearchaeota is also rarely found in hot springs and marine plankton. Interestingly, Woesearchaeota were spread in several inland saline lakes of the Monegros desert (Casamayor et al ., ). For most of the archaeal lineages, the primers 515f and 806r (Caporaso et al ., ) showed a full coverage of the sequences on the SILVA 119 and 123 databases (SILVA TestPrime, Klindworth et al ., ).…”

“…These biases were not detected for the primers pair 344f‐915r usually used in environmental DGGE studies (e.g. Casamayor et al ., ). Therefore, we can rule out a major effect of priming bias in the present study but the results obtained in former studies in the area should be carefully analysed.…”

Deep sequencing uncovers protistan plankton diversity in the Portuguese Ria Formosa solar saltern ponds

“…An edge weight (sequence similarity) of 90 % was chosen to discriminate between the different swarms ◂ Novel diversity in solar salterns Investigating genetic novelty in molecular datasets is an ascending subject in diversity research (Lynch et al 2012;Casamayor et al 2013;Triadó-Margarit and Casamayor 2013). Several approaches exist to target this issue: while Casamayor et al (2013) and Triadó-Margarit and Casamayor (2013) explored genetic novelty of their DGGEsequences by BLAST identity searches, retaining and relating the closest environmental match and the closest cultured match, Lynch et al (2012) proposed a strategy suitable for high-throughput data. They conducted network analyses of their bacterial data, combining taxonomic affiliation, sequence similarity to a BLAST hit, as well as sequence similarity information between sequences and were able to identify numerous sequence clusters of phylogenetic novelty.…”

Environmental distribution of two widespread uncultured freshwater Euryarchaeota clades unveiled by specific primers and quantitative PCR

“…In cold and mesophilic environments, methanogens and extreme halophiles (Haloarchaea) have been studied for Quantitative distribution of uncultured Euryarchaeota 864 a long time and have well-known functional roles. Methanogens are active key players in anoxic waters and sediments (Garcia et al, 2000), and Euryarchaeota show prevalence over other archaeal phyla for high-salinity environments such as the MSBL-1 candidate order, the Halobacteriaceae and the DHVEG-6 clade (van der Wielen et al, 2005;Auguet et al, 2010;Casamayor et al, 2013). The most widely encountered uncultured euryarchaeotal lineages found in freshwater environments are the MEG and DSEG lineages, along with the Marine Benthic Group D (MBG-D) (Galand et al, 2006;Barberán et al, 2011;Borrel et al, 2012).…”