Molecular characterization of phototrophic microorganisms in the forefield of a receding glacier in the Swiss Alps

Abstract

Recently deglaciated areas are ideal environments to study soil formation and primary microbial succession where phototrophic microorganisms may play a role as primary producers. The aim of our study was to investigate the cyanobacterial and green algal community composition in three different successional stages of the Damma glacier forefield in the Swiss Alps using 16S rDNA and ITS rDNA clone libraries. Cyanobacterial target sequences varied along the glacier forefield, with the highest cyanobacterial 16S rRNA gene copies found in sparsely vegetated soils. Sequence analysis revealed that the phototrophic communities were distinct in each of the three soil environments. The majority of the cyanobacterial sequences retrieved from barren soils were related to the Oscillatoriales. The diversity in sparsely vegetated soils was low, and sequences closely related to Nostoc sp. dominated. The majority of the algal phylotypes are related to members of the Trebouxiophyceae known to live as symbiotic partners in lichens. We conclude that the community composition appears to shift markedly along the chronosequence, indicating that each soil environment selects for its phototrophic community. When cyanobacteria occur together with eukaryotic microalgae, they form a rich source of organic matter and may be important contributors of carbon in nutrient-deficient deglaciated soils.

Microbial communities and primary succession in high altitude mountain environments

“…Mineral soils and glacier stream sediments host a remarkably high microbial diversity, as shown in several researches (Nicol et al 2005;Branda et al 2010;Buzzini et al 2012;Frey et al 2013;Wilhelm et al 2013). Among the most common bacterial phyla, Acidobacteria seem to be more common in mineral soil with low carbon and nitrogen content, and neutral or alcaline pH, whereas Bacteroidetes seem to colonize acidic soil with organic matter supplied by mosses.…”

“…1). Consequently, bacteria, archaea, fungi, and algae are crucial and fundamental actors capable of enriching mineral soil of nitrogen and carbon (Jumpponen et al 2002;Nicol et al 2006;Zumsteg et al 2012;Frey et al 2013). On the other side, microbial respiration, methanogenesis, denitrification and anammox act as opposite processes, leading to a loss of nutrients and organic matter.…”

Potential sources of microbial colonizers in an initial soil ecosystem after retreat of an alpine glacier

“…However, inputs of C, N (as DON, nitrate and ammonium) and other nutrients (for example, sulphate and phosphate) from atmospheric deposition represent important inputs to nutrient and C pools, which are known to be small in barren soils (Bernasconi et al, 2011;Smittenberg et al, 2012). Therefore, these inputs may facilitate the establishment of pioneer microbial communities in the mineral debris (Frey et al, 2010(Frey et al, , 2013Brunner et al, 2011). The simultaneous investigation of bacterial and fungal communities present in atmospheric deposition, endogenous glacial habitats and barren soils revealed interesting patterns.…”

Nature of the Belowground Ecosystem and Its Development during Pedogenesis

“…For instance, Cyanobacterial community composition on the Damma glacier forefield was shown to be distinct in each of three (0-10, 60-70, and 110-120 years) successional stages and the community was largest at the initial site (Frey et al, 2013).These workers also found that the green algal community structure differed substantially between the younger and developed (110-120 years) soils. For instance, Cyanobacterial community composition on the Damma glacier forefield was shown to be distinct in each of three (0-10, 60-70, and 110-120 years) successional stages and the community was largest at the initial site (Frey et al, 2013).These workers also found that the green algal community structure differed substantially between the younger and developed (110-120 years) soils.…”

“…Phototrophic microorganisms (e.g., cyanobacteria and green algae) are early colonizers of recently deglaciated soil (Kastovska et al, 2005;Stibal et al, 2006;Frey et al, 2013) and can be a significant source of new organic C (Stibal et al, 2008;Anesio et al, 2009;Freeman et al, 2009) during early succession. Frey et al (2013) found that although cyanobacteria were highest in sparsely vegetated soils (60-70 years) on the Damma glacier, there was a substantial community present in barren soils (0-10 years).…”