Dorador, Cristina (2007) Microbial communities in high altitude altiplanic wetlands in northern Chile: phytogeny, diversity and function. (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, Germany, 166 pp.

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Abstract

The phylogeny, diversity and function of microbial communities from several altiplanic wetlands was examined using an array of different but complimentary techniques. Results highlighted that microbial diversity exhibited a specific pattern in each wetland. Bacteria were dominant over Archaea in both freshwater and saline systems. Bacterial and archaeal diversity were both higher in sediment than in water samples. Lago Chungará, Laguna de Piacota and Bofedal de Parinacota are freshwater wetlands located at high altitude (>4400 m) in the north of Chile. They support microbial communities closely related to psychrophilic bacteria (e.g. Psychrobacter sp., Pseudomonas congelans, Flavobacterium psychrolimnae) in water and Proteobacteria and Actinobacteria in sediment samples. Salar de Huasco and Salar de Ascotán are located further south at an altitude of 3800 m and exhibit a wide range of salinities (varying between freshwater to 120 gL-1 of total dissolved salts). Microbial communities in these sites were characterized by bacteria tolerant to salt (e.g. halophilic Bacteria: Halomonas sp., halophilic Archaea: Halorubrum sp.). Cytophaga-Flavobacteria-Bacteroidetes was the most frequent group reported at the sites. In-depth studies focussing on the Salar de Huasco revealed a particular diversity of Archaea, characterized by a number of sequences related to uncultured groups and ammonia-oxidizing Crenarchaeota. Cyanobacteria from the Salar de Huasco were closely related to Cyanobacteria previously described from Antarctica. Isolates of halophilic bacteria and phototrophic bacteria displayed an elevated tolerance to different salt concentrations. The particular microbial diversity found in high altitude wetlands provides a new and exciting area of research.

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