Marked Succession of Cyanobacterial Communities Following Glacier Retreat in the High Arctic

Abstract

Cyanobacteria are important colonizers of recently deglaciated proglacial soil but an in-depth investigation of cyanobacterial succession following glacier retreat has not yet been carried out. Here, we report on the successional trajectories of cyanobacterial communities in biological soil crusts (BSCs) along a 100-year deglaciation gradient in three glacier forefields in central Svalbard, High Arctic. Distance from the glacier terminus was used as a proxy for soil age (years since deglaciation), and cyanobacterial abundance and community composition were evaluated by epifluorescence microscopy and pyrosequencing of partial 16S rRNA gene sequences, respectively. Succession was characterized by a decrease in phylotype richness and a marked shift in community structure, resulting in a clear separation between early (10-20 years since deglaciation), mid (30-50 years), and late (80-100 years) communities. Changes in cyanobacterial community structure were mainly connected with soil age and associated shifts in soil chemical composition (mainly moisture, SOC, SMN, K, and Na concentrations). Phylotypes associated with early communities were related either to potentially novel lineages (< 97.5% similar to sequences currently available in GenBank) or lineages predominantly restricted to polar and alpine biotopes, suggesting that the initial colonization of proglacial soil is accomplished by cyanobacteria transported from nearby glacial environments. Late communities, on the other hand, included more widely distributed genotypes, which appear to establish only after the microenvironment has been modified by the pioneering taxa.

Strong in combination: Polyphasic approach enhances arguments for cold‐assigned cyanobacterial endemism

“…The frozen habitats might then provide a pool of propagules for microbial colonization, which is supported by the fact that microbial assemblages in ice and soil habitats are relatively similar (Kaštovská et al, 2007;Wynn-Williams, 1990). This has recently been supported by , Pessi, Pushkareva, et al (2018), who found that cyanobacteria transported from nearby glacial environments are the main colonizers of ice-free soil following glacier retreat. On a worldwide scale, various factors regarding longrange dispersal of microorganisms between and across both polar regions have also been identified: Atmospheric circulation can transport spores or even cells over large distances (Elster, Delmas, Petit, & Reháková, 2007;González-Toril et al, 2009), and marine migratory birds, which are known to cross the two hemispheres (Schlichting, Speziale, & Zink, 1978), may introduce alien strains.…”

“…; Pessi, Pushkareva, et al. ). In contrast, in alpine habitats, the community composition appears to shift markedly along chrono‐sequences, indicating that each soil environment selects for its phototrophic community (Frey, Bühler, Schmutz, Zumsteg, & Furrer, ).…”

“…(), Pessi, Pushkareva, et al. (), who found that cyanobacteria transported from nearby glacial environments are the main colonizers of ice‐free soil following glacier retreat. On a worldwide scale, various factors regarding long‐range dispersal of microorganisms between and across both polar regions have also been identified: Atmospheric circulation can transport spores or even cells over large distances (Elster, Delmas, Petit, & Reháková, ; González‐Toril et al., ), and marine migratory birds, which are known to cross the two hemispheres (Schlichting, Speziale, & Zink, ), may introduce alien strains.…”

“…Currently, terrestrial aspects of cold ecosystems with high BSC coverage found at Hochtor (European Alps), Geopol, Ny-Ålesund (both Arctic, Svalbard), and Livingston Island (Antarctica) have been addressed (Jung, Briegel-Williams, Simon, Thyssen, & Büdel, 2018;Rippin et al, 2018;Williams, Borchhardt, et al, 2017), but the cyanobacterial community composition received little attention. In Svalbard high bacterial abundance was found in vegetated soils, this was strongly related to the availability of organic matter, inorganic nutrients, and moisture supply (Kaštovská, Elster, Stibal, & Šantrůčková, 2005;Pessi, Pushkareva, et al 2018). In contrast, in alpine habitats, the community composition appears to shift markedly along chrono-sequences, indicating that each soil environment selects for its phototrophic community (Frey, Bühler, Schmutz, Zumsteg, & Furrer, 2013).…”

Disappearing Kilimanjaro snow—Are we the last generation to explore equatorial glacier biodiversity?

“…Also equatorial, glacier-fed streams present unique hydraulic patterns when compared to temperate regions, and taxon richness in glacier-fed streams of the Ecological Reserve of Antisana (Ecuador) will be significantly reduced following glacier shrinking (Cauvy-Fraunié et al, 2013). But these equatorial glaciers are also unique ecosystems and may be sources of nutrients and first migrants in cold water streams (Bagshaw et al, 2013;Dresch et al, 2019;Pessi et al, 2018).…”