Physicochemical Parameters Affecting the Distribution and Diversity of the Water Column Microbial Community in the High-Altitude Andean Lake System of La Brava and La Punta.

Reynaldo Núñez Salazar,Carlos Aguirre,Humberto Prieto,Carlos Salinas,Manuel Paneque,Jorge Soto,Pamela Salinas

doi:10.3390/microorganisms8081181

Reynaldo Núñez Salazar, Carlos Aguirre + Show 5 more

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https://doi.org/10.3390/microorganisms8081181

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Abstract

Due to the low incidence of precipitation attributed to climate change, many high-altitude Andean lakes (HAALs) and lagoons distributed along the central Andes in South America may soon disappear. This includes La Brava–La Punta, a brackish lake system located south of the Salar de Atacama within a hyper-arid and halophytic biome in the Atacama Desert. Variations in the physicochemical parameters of the water column can induce changes in microbial community composition, which we aimed to determine. Sixteen sampling points across La Brava–La Punta were studied to assess the influence of water physicochemical properties on the aquatic microbial community, determined via 16S rRNA gene analysis. Parameters such as pH and the concentrations of silica, magnesium, calcium, salinity, and dissolved oxygen showed a more homogenous pattern in La Punta samples, whereas those from La Brava had greater variability; pH and total silica were significantly different between La Brava and La Punta. The predominant phyla were Proteobacteria, Bacteroidetes, Actinobacteria, and Verrucomicrobia. The genera Psychroflexus (36.85%), Thiomicrospira (12.48%), and Pseudomonas (7.81%) were more abundant in La Brava, while Pseudospirillum (20.73%) and Roseovarius (17.20%) were more abundant in La Punta. Among the parameters, pH was the only statistically significant factor influencing the diversity within La Brava lake. These results complement the known microbial diversity and composition in the HAALs of the Atacama Desert.

Highlights

Pristine high-altitude Andean lakes (HAALs) can be found along the central Andes of South America [1,2]
The diversity and composition of microbes varied at different sampling points depending on the physicochemical parameters that result from the recharge and discharge of the lake system and the isolated bodies formed during the dry season [7,62]
This study is the first to simultaneously analyze the aquatic microbial diversity and composition of the La Brava and La Punta HAALs located in the southern section of the Salar of Atacama

Summary

Introduction

Pristine high-altitude Andean lakes (HAALs) can be found along the central Andes of South America [1,2]. This aquifer facilitates the formation of wetlands and salty meadows and flows through a salt interface that ends up forming the shallow and saline La Brava–La Punta lake system [6]. This shallow lake ecosystem suffers from a decline in water levels resulting from permanent evaporation (137.48 ± 0.09 mm per year [5]), which causes it to recede or disappear during the dry season [7,8,9]. Other extreme conditions, such as low nutrient availability [2], influence the microbial community composition [11]

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