Abstract

MONTOYA T, Haydee et al. Cryophilic communities of the Allincapac mountain glaciers, southern Peruvian Andes, Puno Department: Phenotypic variability of the cyanobacterium Nostoc commune (Nostocales, Nostocaceae). Arnaldoa [online]. 2019, vol.26, n.2, pp.657-674. ISSN 1815-8242.  http://dx.doi.org/10.22497/arnaldoa.261.26209.

Peruvian terrestrial ecosystems encompass an extension about 71 % of the world’s tropical glaciers. The cryosphere in the surroundings of Allincapac mountain glacier, Carabaya Cordillera, southern Peruvian Andes was evaluated between 4500 and 4700 m of altitude. Standard collections of cyanobacteria and microalgae were done by scraping the biofilms or crusts from cliffs or slopes of calcareous mountains. They were carried out in summer season (February 2018) and winter (August 2017). The thermogradients were between 0 and 10 °C and pH between 6.0 and 6.5. This extreme ecosystem, threatened by the climate change, has habitats colonized by litophilic, chasmolithic and subaerophytic communities. Colonization of cryophilic cyanobacteria and microalgae with dominance of colonial thalli of Nostoc commune showed their adaptation to freeze and desiccation, as well as deglaciation and hydration periods. Phenotypic variability in N. commune was recognized by its morphotypes (hormogonial stage, seriate and aseriate growth, sheath structure, heterocysts and akinetes development) during the stages of the life cycle. In addition, its phenotypic plasticity is favored by morphophysiological strategies against freeze and thaw, desiccation, ultraviolet radiation (complex mucilage), by its diazotrophic ability, and ecological strategies for propagation and survival (akinetes) in the highlands. Therefore, this cryophilic species can be considered as candidate for extraterrestrial experiments during space missions.

Keywords : cryosphere; biofilms; morphotypes; lithophilic; chasmolithic; subaerophytic.

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