Hyperexpansion of Genetic Diversity and Metabolic Capacity of Extremophilic Bacteria and Archaea in Ancient Andean Lake Sediments
The Andean Altiplano hosts a repertoire of high-altitude lakes with harsh conditions for life. These lakes are undergoing a process of desiccation caused by the current climate, leaving terraces exposed to extreme atmospheric conditions and serving as analogs to Martian paleolake basins.
Microbiomes in Altiplano lake terraces have been poorly studied, enclosing uncultured lineages and a great opportunity to understand environmental adaptation and the limits of life on Earth.
Here we examine the microbial diversity and function in ancient sediments (10.3–11 kyr BP (before present)) from a terrace profile of Laguna Lejía, a sulfur- and metal/metalloid-rich saline lake in the Chilean Altiplano.
We also evaluate the physical and chemical changes of the lake over time by studying the mineralogy and geochemistry of the terrace profile.
Study site and sampling area located in the Altiplano–Puna Plateau in the Central Andes. a and b show a sequential zoom of the location of Laguna Lejía (red pin) in northern Chile, where the Altiplano–Puna Volcanic Complex (APVC) is located. c shows the endorheic basin of Laguna Lejía surrounded by the active volcanoes Lascar and Simba. d shows the panoramic view of Laguna Lejía showing the terraces and the dry shore due to water retreat over the years. The white box indicates the location of the sampled sediment profile, located the first meter above the base of the terrace. e shows the ~1-m high vertical profile sampled. f and g zoom in the sampled profile and show the six sediment layers collected from the bottom (A) to top (F) based on their different color and texture. Starting from the first meter of the terrace, samples were collected from 1 to 1.07 m (A), 1.08 to 1.09 m (B), 1.10 to 1.35 m (C), 1.36 to 1.38 m (D), 1.39 to 1.70 m (E) and 1.71 to 1.95 m (F) high. Pictures a, b, and c are from Google Earth. — via PubMed
Maximum Likelihood unrooted phylogenies (model selected in IQ-TREE by Modelfinder) of the new a 572 bacterial genomes and b 19 archaeal genomes reconstructed from the Laguna Lejía terrace. Phylogenies were constructed using a concatenation of 30 ribosomal proteins. In brackets, the number of MAGs at the phylum level. — via PubMed
Hyperexpansion of genetic diversity and metabolic capacity of extremophilic bacteria and archaea in ancient Andean lake sediments, Microbiome. 2024; 12: 176. Published online 2024 Sep 17. doi: 10.1186/s40168-024-01878-x (open access) via PubMed
Astrobiology