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Laguna Tebenquiche is one of the largest waterbodies in the Salar de Atacama. The prokaryotic microorganisms inhabiting this lake are subjected to extreme conditions such as high solar radiation due to a lower barometric pressure at high altitude, extreme daily temperature fluctuations, severe changes in salinity caused by net evaporation, and high arsenic concentrations in the water owing to volcanic events. The microbial community of Laguna Tebenquiche was studied using culture-dependent and culture-independent molecular methods and more recently, metagenomic analyses. These multifarious approaches allowed determination of the prokaryotic diversity in the various microbial ecosystems comprising Laguna Tebenquiche. Here, we describe the main results from the different approaches/analyses, the most relevant results for understanding the ecology of this extreme environment, and discuss future perspectives for diversity/microbial ecological studies.

Peatlands are plant formations established in an edaphic environment, mainly organic, characterized by a water condition of permanent saturation, which works as an oasis that promotes abundant biological diversity in the arid high-altitude environment. Peatlands present cultural, environmental, and economic social relevance because they are sources of life and development for people who live in and depend on these ecosystems. These wetlands have begun to dry up, consequently leading to the loss of natural resources (flora and fauna) and damage to the ancestral rights to natural resources (including water) of indigenous communities, due to the acquisition and exploitation of water rights for non-agricultural uses (mainly mining) that are endangering the sustainability and survival of these groups. The relationship between microbial diversity and function in soil is largely unknown, but biodiversity is assumed to influence ecosystem stability, productivity, and resilience toward stress and disturbance. In this chapter, we will present the first performed approach of microbial diversity in peatland soils.

Salar de Llamara is situated in the north of the Atacama Desert, which is the driest desert and one of the most irradiated places on Earth. Besides, its subterranean hypersaline waters contain a high content of arsenic, among other compounds such as heavy metals that are poisonous to life in the concentrations present. Despite these extreme conditions, diverse microbial communities flourish in gypsum stratified ecosystems (microbial mats and evaporitic domes).

The Salar de Atacama depression is a unique geomorphologic structure in northern Chile and is the oldest and largest evaporitic basin in that country. In the lowest region of the Atacama basin, groundwater surfaces forms a series of lakes that are exposed to the extreme conditions of the salar, including high ultraviolet radiation, low humidity, high water-column conductivity, and arsenic concentrations. Among these lakes, Laguna La Brava harbors a variety of living microbialites and microbial mats. Several studies have determined the microbial diversity and the genomic basis of the main metabolic pathways that allow these microbial ecosystems to thrive in such extreme conditions, which resemble Precambrian/Paleoproterozoic conditions. This chapter reviews the results published since these unusual ecosystems were first described 4 years ago.