We evaluated the microbial diversity and metabolome profile of an uncommon hypersaline elastic microbial mat from Cuatro Ciénegas Basin (CCB) in the Chihuahuan Desert of Coahuila, México. We collected ten samples on a small scale transect (1.5-m) and described its microbial diversity through NGS-based ITS and 16S rDNA gene sequencing. A very low number of taxa comprised a considerable proportion of the mat and were shared across all sampling points, whereas the rare biosphere was more phylogenetically diverse (Faith’s Phylogenetic Diversity (FPD) index) and phylogenetically disperse (using a null model distribution of Phylogenetic Species Clustering (nmdPSC)) than the abundant (high read count) taxa for both analyzed libraries. We also found a distinctive metabolome profile for each sample and were able to tentatively annotate several classes of compounds with relevant biological properties.

We evaluated the microbial diversity and metabolomic signatures of a hypersaline elastic microbial mat from Cuatro Cienegas Basin (CCB) in the Chihuahuan Desert of Coahuila, Mexico. We collected ten samples within a small scale (1.5-meters transect) and found a high microbial diversity through NGS-based ITS and 16S rRNA gene sequencing. A very low number of taxa were abundant and shared between all sites, whereas the rare biosphere was more phylogenetically diverse (FPD index) and phylogenetically disperse (PSC index) than the abundant taxa for both analyzed libraries. In regard to potential biotic interactions (Pearson analysis), there were more positive correlations than negative. We also found a distinctive metabolomic signature for each sample and were able to tentatively annotate several classes of compounds with relevant biological properties. Together, these results reveal cohesive, diverse and fluctuating microbial communities, where abundant and rare taxa appear to have different ecological roles.

Pozas Rojas is a hydrological system comprising nine isolated shallow ponds and a deep lagoon, which were temporally merged in 2010 by increased rainfall due to a tropical cyclone. In this work, we assess which components, biotic interactions, or environment filtering effects, drive the assembly of microbial communities after a natural perturbation. Arsenic, pH, and temperature are among the most significant environmental variables between each pond, clustering the samples in two main groups, whereas microbial composition is diverse and unique to each site, with no core at the operational taxonomic unit level and only 150 core genera when studied at the genus level. Los Hundidos lagoon has the most differentiated community, which is highly similar to the epipelagic Mediterranean Sea communities. On the other hand, the shallow ponds at the Pozas Rojas system resemble more to epicontinental hydrological systems, such as some cold rivers of the world and the phreatic mantle from Iowa. Overall, despite being a sole of water body 2 years prior to the sampling, interspecific interactions, rather than environmental selection, seem to play a more important role in Pozas Rojas, bolstered by founder effects on each poza and subsequent isolation of each water body.