“Salars” are found in the central depression of the Andean Altiplano region of Chile. Salars are formed by the upwelling of groundwater, which evaporates at the ground surface to form salt-rich flat lakes. Salars are a scarce source of surface water that sustains unique aquatic and terrestrial ecosystems. Located at approximately 4 Km above sea level, Salars are subjected to severe environmental conditions including low humidity and extreme temperature/wind patters (Figure 1). Nevertheless, thin layers of bacteria and microalgae (diatoms and cyanobacteria) are at the base of the food chain in these ecosystems and can be found below the water-sediment interface of the lakes. Recent observations at the Salar del Huasco (Chile) suggest the Salars have a special value in the context of climate change mitigation, because these aquatic ecosystems are a sink of atmospheric CO2. This study uses field observations and numerical models to characterize and quantify the mechanism governing CO2 flux (FCO2) in/out the Salars. In particular, this study focuses on the importance of algae growth in response to the wind-induced turbulence in water, considering the diurnal and seasonal variability of the atmospheric conditions. Preliminary results suggest that carbon is a limiting factor for algal growth in these aquatic systems, and the rate at which atmospheric CO2 diffuses across the air-water interface (AWI) is driven by algal production. Figure 1 shows a time series of the flux of atmospheric CO2 into the Huasco Salar. The main source of carbon to the Salars is groundwater and concentrations are small compared atmospheric CO2. Thus, atmospheric CO2 could be stored in the biomass of the Salars. Further, the implications of these unique ecosystems in the regional carbon cycle and their potential as engineered “phyto-lungs” will be discussed.

Mechanisms governing algal remediation of atmospheric CO2 in shallow saline lakes of the Chilean Altiplano region

254th National Meeting (2017)

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