Microbial communities and primary succession in high altitude mountain environments

Abstract

In high mountain environments, microbial communities are key players of soil formation and pioneer plant colonization and growth. In the last 10 years, many researches have been carried out to highlight their contribution. Bacteria, fungi, archaea, and algae are normal inhabitants of the most common habitats of high altitude mountains, such as glacier surfaces, rock wall surfaces, boulders, glacier waters, streams, and mineral soils. Here, microbial communities are the first colonizers, acting as keystone players in elemental transformation, carbon and nitrogen fixation, and promoting the mineral soil fertility and pioneer plant growth. Especially in high mountain environments, these processes are fundamental to assessing pedogenetic processes in order to better understand the consequences of rapid glacier melting and climate change. This review highlights the most important researches on the field, with a particular view on mountain environments, from glaciers to pioneer plant growth.

Ecosystem engineers: Biofilms and the ontogeny of glacier floodplain ecosystems

“…Thus, biofilms may be important in determining where vegetation can develop ( Figure 5; Miller & Lane, 2019). Additionally, biofilms should increase the amount of soil nutrients available for plants to grow (Ciccazzo, Esposito, Borruso, & Brusetti, 2016;Kaštovská, Elster, Stibal, & Šantrů cková, 2005;Schulz et al, 2013), which further explains why terraces are not fully covered by vegetation (see the upper-right part of Figure 5b). This effect may be a lateral one related to terraces but also a longitudinal one due to the attenuation described above.…”

“…These conditions allow biofilms to trigger their engineering feedbacks, in which biostabilization increases fertilization, and vice versa. These feedbacks drive an increase of the organic matter content of sediments (Miller & Lane, 2019), promoting primary succession (Ciccazzo et al, 2016;Raab et al, 2012) (Figure 6c).…”

Emerging from the ice‐fungal communities are diverse and dynamic in earliest soil developmental stages of a receding glacier

“…Glacier forefields provide valuable areas for studying the development and colonization of newly exposed soils. Micro‐organisms are the first life forms to colonize freshly exposed substrates and play a tremendous role in soil formation (Sigler et al, ; Sigler and Zeyer, ; Sigler and Zeyer, ; Nicol et al, ; Bardgett et al, ; Nemergut et al, ; Schmidt et al, ; Ciccazzo et al, ). Biological soil crusts consist of typical pioneer organisms (bacteria including cyanobacteria, fungi, algae and lichens) colonizing the soil surface and subsurface.…”

Prokaryotic community shifts during soil formation on sands in the tundra zone

“…While the succession of plant communities is relatively well studied, information on the prokaryotic community assemblage during soil formation is still lacking. It is known that the first organisms to colonize parent rock are phototrophs, diazotrophs, chemolithotrophs and heterotrophs, whose taxonomic composition depends on the substrate properties [4,8]. Several bacterial phyla have been suggested to be associated with the initial stages of soil formation, mainly Bacteroidetes [3] and Cyanobacteria [12,13].…”

“…Available nitrogen is a limiting factor of plant growth, especially on lean substrates in cold environments [14–16]. Prokaryotes are able to perform nitrogen fixation, which leads to the accumulation of available nitrogen during inhabitation of barren substrates, such as rocks and sands [4]. Both archaeal and bacterial ammonia oxidizers produce nitrate (NO 3 − ), which appears to be a crucial form of nitrogen for plants in the tundra zone [17].…”