Modern Stromatolite Ecosystems at Alkaline and Hypersaline High-Altitude Lakes in the Argentinean Puna

Farı́as, Marı́a Eugenia; Poiré, Daniel Gustavo; Arrouy, María Julia; Albarracín, Virginia Helena

doi:10.1007/978-94-007-0397-1_19

Cited by 27 publications

(23 citation statements)

References 19 publications

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“…The presence of these minerals was confirmed by X-ray diffraction, which further showed that aragonite dominated over calcite (see Ref. [21]). …”

Section: Resultsmentioning

confidence: 74%

“…To the best of our knowledge, this is so far the highest altitude where actively forming stromatolites have been found. Following the preliminary characterization by Farías and colleagues [21], this study provides a more detailed description of the stromatolites with respect to the characteristics of their habitat, composition of their mineral phase and microbiota, and some aspects of microbial activity and physiology. We compare the Socompa stromatolites with other modern stromatolites, and hypothesize how the combined effects of the environment and the in situ microbial activity determine the stromatolites formation.…”

Section: Introductionmentioning

confidence: 99%

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The Discovery of Stromatolites Developing at 3570 m above Sea Level in a High-Altitude Volcanic Lake Socompa, Argentinean Andes

et al. 2013

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We describe stromatolites forming at an altitude of 3570 m at the shore of a volcanic lake Socompa, Argentinean Andes. The water at the site of stromatolites formation is alkaline, hypersaline, rich in inorganic nutrients, very rich in arsenic, and warm (20–24°C) due to a hydrothermal input. The stromatolites do not lithify, but form broad, rounded and low-domed bioherms dominated by diatom frustules and aragonite micro-crystals agglutinated by extracellular substances. In comparison to other modern stromatolites, they harbour an atypical microbial community characterized by highly abundant representatives of Deinococcus-Thermus, Rhodobacteraceae, Desulfobacterales and Spirochaetes. Additionally, a high proportion of the sequences that could not be classified at phylum level showed less than 80% identity to the best hit in the NCBI database, suggesting the presence of novel distant lineages. The primary production in the stromatolites is generally high and likely dominated by Microcoleus sp. Through negative phototaxis, the location of these cyanobacteria in the stromatolites is controlled by UV light, which greatly influences their photosynthetic activity. Diatoms, dominated by Amphora sp., are abundant in the anoxic, sulfidic and essentially dark parts of the stromatolites. Although their origin in the stromatolites is unclear, they are possibly an important source of anaerobically degraded organic matter that induces in situ aragonite precipitation. To the best of our knowledge, this is so far the highest altitude with documented actively forming stromatolites. Their generally rich, diverse and to a large extent novel microbial community likely harbours valuable genetic and proteomic reserves, and thus deserves active protection. Furthermore, since the stromatolites flourish in an environment characterized by a multitude of extremes, including high exposure to UV radiation, they can be an excellent model system for studying microbial adaptations under conditions that, at least in part, resemble those during the early phase of life evolution on Earth.

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“…The presence of these minerals was confirmed by X-ray diffraction, which further showed that aragonite dominated over calcite (see Ref. [21]). …”

Section: Resultsmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

The Discovery of Stromatolites Developing at 3570 m above Sea Level in a High-Altitude Volcanic Lake Socompa, Argentinean Andes

et al. 2013

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“…There are currently no meteorological stations in the region of the Laguna Verde Complex, and the climatic information for the Puna region is limited; Table 1 provides meteorological and environmental data reported from the Pascua Lama-Veladero mining district, which lies , 230 km to the southwest of (and at a comparable altitude to) the Laguna Verde Complex, as well as data reported from elsewhere in the Puna region (Fernandez-Zenoff et al 2006;Ordoñez et al 2009;Farías et al 2011). A meteorological station has been acquired and will be installed at Laguna Negra in 2014, as part of an ongoing environmental monitoring project.…”

Section: Environmental and Climate Datamentioning

confidence: 97%

“…Modern stromatolites have been described by Farías et al (2011) for Socompa and Tolar Grande (Salta and Jujuy provinces, Argentina, respectively) and similar modern and recent (Holocene) microbialites have also been described by Risacher and Eugster (1979), Jones and Renault (1994), Rouchy et al (1996) and Valero-Garcés et al (1999 for the Altiplano-Puna region of Chile and Bolivia. Although such terms as pisoids (Risacher and Eugster 1979;Jones and Renault 1994), dendroidal oncolites (Wade and García Pichel 2003) and stromatolitic oncoids (Garcia-Pichel et al 2004) have been used for similar structures, here we refer to them generally as oncoids, although this term does not always reflect the morphological complexity of these structures.…”

Section: Introductionmentioning

confidence: 92%

Microbialites in a High-Altitude Andean Lake: Multiple Controls on Carbonate Precipitation and Lamina Accretion

Gómez¹,

Kah²,

Bartley³

et al. 2014

PALAIOS

128

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Microbialites comprise the mineralized record of early life on Earth and preserve a spectrum of fabrics that reflect complex physical, chemical, and biological interactions. The relatively rarity of microbialites in modern environments, however, challenges our interpretation of ancient structures. Here we report the occurrence of microbial mats, mineral precipitates, and oncoids in the Laguna Negra, a high-altitude hypersaline Andean lake in Catamarca Province, Argentina. Laguna Negra is a Ca-Na-Cl brine where abundant carbonate precipitation takes place. Extreme environmental conditions, including high UV radiation, elevated salinity, and temperature extremes, restrict multicellular life so that mineralization reflects a combination of local hydrologic conditions, lake geochemistry, and microbial activity. The resulting carbonates consist of micritic laminae, botryoidal cement fans, and isopachous cement laminae that are strikingly similar to those observed in Proterozoic stromatolites, providing insight into mechanisms of mineralization. Here, increased saturation with respect to carbonate minerals reflects mixing of spring-fed inlets and lake waters, favoring microbialite formation and preservation. This highlights the importance of hydrological mixing zones in microbialite formation and as taphonomic windows to record microbial activity. Recent discoveries of minerals related to evaporating playa-lake systems on Mars further highlights the potential of Laguna Negra to provide critical insight into biosignature preservation in both terrestrial and extraterrestrial settings.

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“…The HAAL ecosystems are systems of shallow lakes formed during the Tertiary geological period (Seufferheld et al, 2008;Farias et al, 2011). These ecosystems are unique not only for their geographical characteristics and broad range of extreme environments but also for their abundant biodiversity (Fernandez Zenoff et al, 2006;Dib et al, 2008;Seufferheld et al, 2008;Flores et al, 2009;Ordoñez et al, 2009;Albarracín et al, 2011;Farias et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Genome comparison of two Exiguobacterium strains from high altitude andean lakes with different arsenic resistance: identification and 3D modeling of the Acr3 efflux pump

Ordoñez

Lanzarotti

Kurth

et al. 2015

Front. Environ. Sci.

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Arsenic exists in natural systems in a variety of chemical forms, including inorganic arsenite (As [III]) and arsenate (As [V]). The majority of living organisms have evolved various mechanisms to avoid occurrence of arsenic inside the cell due to its toxicity. Common core genes include a transcriptional repressor ArsR, an arsenate reductase ArsC, and arsenite efflux pumps ArsB and Acr3. To understand arsenic resistance we have performed arsenic tolerance studies, genomic and bioinformatic analysis of two Exiguobacterium strains, S17 and N139, from the high-altitude Andean Lakes. In these environments high concentrations of arsenic were described in the water due to a natural geochemical phenomenon, therefore, these strains represent an attractive model system for the study of environmental stress and can be readily cultivated. Our experiments show that S17 has a greater tolerance to arsenite (10 mM) than N139, but similar growth in arsenate (150 mM). We sequenced the genome of the two Exiguobacterium and identified an acr3 gene in S17 as the only difference between both species regarding known arsenic resistance genes. To further understand the Acr3 we modeled the 3D structure and identified the location of relevant residues of this protein. Our model is in agreement with previous experiments and allowed us to identify a region where a relevant cysteine lies. This Acr3 membrane efflux pump, present only in S17, may explain its increased tolerance to As(III) and is the first Acr3-family protein described in Exiguobacterium genus.

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Modern Stromatolite Ecosystems at Alkaline and Hypersaline High-Altitude Lakes in the Argentinean Puna

Cited by 27 publications

References 19 publications

The Discovery of Stromatolites Developing at 3570 m above Sea Level in a High-Altitude Volcanic Lake Socompa, Argentinean Andes

The Discovery of Stromatolites Developing at 3570 m above Sea Level in a High-Altitude Volcanic Lake Socompa, Argentinean Andes

Microbialites in a High-Altitude Andean Lake: Multiple Controls on Carbonate Precipitation and Lamina Accretion

Genome comparison of two Exiguobacterium strains from high altitude andean lakes with different arsenic resistance: identification and 3D modeling of the Acr3 efflux pump

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