Greenhouse gases budgets an active role of microbial mats at a High altitude wetland ecosystem (Salar de Huasco, Chile). GEI_SALAR

Salar de Huasco is a high altitude wetland of the Andes plateau situated at 3,800 masl, characterized by high sun radiation <1,600 W m-2, extreme temperature changes (-12 -24ºC), wind stress (0-17 m s-1). The water source of the wetland is mainly groundwater springs, which generates streams and ponds surrounded by peatlands. These sites hold a rich aquatic life including diverse bacteria and archaea, which transiently forms more complex structures, such as microbial mats. Herein, we evaluate the contribution of these sites to carbon dioxide, methane and nitrous oxide greenhouse gases (GHG) by chromatography analyses of the water using headspace and extrapolation based on DRON flight for area estimations. The microbial community where survey using metagenomic and 16S rRNA barcode through massive sequencing (illumina). The results indicate that the spring, stream and ponds with microbial mats, have a differential contribution to GHG, characterized by a respectively increase of methane (55, 160, 5,099 g y-1) and a decrease of carbon dioxide emission (4,253, 3,182, 2,273 g y-1), and a sink of nitrous oxide (-25 - -61 g y-1). Metagenomic analyses indicate that the mats were dominated by bacteria (78%), Archaea (0.13%), Eukaryotes (2.9%) and viruses (0.3%). Archaea were mainly methanogens from diverse genera, e.g., Methanoregula, Methanosaeta, Methanosphaerula, Methanocorpusculum, Methanosarcina. This result was supported by 16S rRNA results, but fewer archaea were detected. In total our results suggest the relevance of microbial mats in carbon cycling in this high altitude wetland, representing a source of methane but a sink of nitrous oxide.