The High‐Lakes Project

Abstract

[1] The High Lakes Project is a multidisciplinary astrobiological investigation studying high-altitude lakes between 4200 m and 6000 m elevation in the Central Andes of Bolivia and Chile. Its primary objective is to understand the impact of increased environmental stress on the modification of lake habitability potential during rapid climate change as an analogy to early Mars. Their unique geophysical environment and mostly uncharted ecosystems have added new objectives to the project, including the assessment of the impact of low-ozone/high solar irradiance in nonpolar aquatic environments, the documentation of poorly known ecosystems, and the quantification of the impact of climate change on lake environment and ecosystem. Data from 2003 to 2007 show that UV flux is 165% that of sea level with maximum averaged UVB reaching 4 W/m 2 . Short UV wavelengths (260-270 nm) were recorded and peaked at 14.6 mW/m 2 . High solar irradiance occurs in an atmosphere permanently depleted in ozone falling below ozone hole definition for 33-36 days and between 30 and 35% depletion the rest of the year. The impact of strong UVB and UV erythemally weighted daily dose on life is compounded by broad daily temperature variations with sudden and sharp fluctuations. Lake habitat chemistry is highly dynamical with notable changes in yearly ion concentrations and pH resulting from low and variable yearly precipitation. The year-round combination of environmental variables define these lakes as end-members. In such an environment, they host ecosystems that include a significant fraction of previously undescribed species of zooplankton, cyanobacterial, and bacterial populations.

Prokaryotic diversity pattern in high‐altitude ecosystems of the Chilean Altiplano

“…The lack of Bacteroidetes in Simba is a differential trait of that lake (Figure 4a). Conversely, in the lake located at the summit of the Licancabur volcano (located in the same geographical area of this study) [ Cabrol et al , 2007a, 2009a], the microbial community composition is similar to microbial communities described from high altitude lakes and characterized by a dominance of Bacteroidetes and Proteobacteria [ Escudero et al , 2007; Cabrol et al , 2007b]. Higher sulfate concentrations were reported from the Simba compared to Licancabur lake (2.5/0.59 gL −1 , respectively) [ Escudero et al , 2007] (Table 2), as well as lower pH (3.9–5.0/6.9–8.5).…”

Photolyases and Cryptochromes in UV‐resistant Bacteria from High‐altitude Andean Lakes

“…1200 J m −2 h −1 . The low latitude and high altitude at HAAL is responsible for a thin ozone layer and a clear sky that favor intense UV radiation, a pattern which is clearly observed in lakes such as the one on the summit of the Licancabur volcano (5917 m) and Laguna Blanca (4340 m) (Bolivia) .…”

Forged Under the Sun: Life and Art of Extremophiles from Andean Lakes

“…With almost unexplored ecosystems, they comprise shallow lakes and wetlands spreading out at up to 6000 m altitude, in a wide range of ecosystems from the Atacama Desert to the Altiplano‐Puna Plateau up to the High Andes. Being exposed to an array of severe climatic and physicochemical conditions, their indigenous microbial communities have managed to thrive in diverse niches: shallow water, sediments, microbial mats and microbialites . As HAAL microorganisms endure such extreme environmental contexts, it is not surprising that NASA has classified some of these lakes as model systems for prospecting life on other planets, a topic of utmost interest within astrobiology .…”