Phylogenetic Clustering Reveals Selective Events Driving the Turnover of Bacterial Community in Alpine Tundra Soils

Shahnavaz, Bahar; Zinger, Lucie; Lavergne, Se ́bastien; Choler, Philippe; Geremia, R.

doi:10.1657/1938-4246-44.2.232

Cited by 9 publications

(11 citation statements)

References 33 publications

(55 reference statements)

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“…In our study, seasonal variations appeared to play a more important role in influencing bacterial and fungal communities than site variations, which is in agreement with previous studies at sites with similar seasonal characteristics (Björk et al, 2008 ; Shahnavaz et al, 2012 ).…”

Section: Discussionsupporting

confidence: 93%

“…At both A and F, we observed a loss of Chloroflexi and Actinobacteria phylotypes in the winter soil samples, whereas Bacteroidetes and Burkholderiales (class β-Proteobacteria) increased. The high relative abundance of copiotrophs under the winter snow suggests high metabolic versatility and adaptation to changing substrates, as noted also by Shahnavaz et al ( 2012 ). The T-RFLP profiles confirmed these trends and indicated that the winter bacterial community is replaced following the spring thaw by a different community.…”

Section: Discussionsupporting

confidence: 67%

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Structures of Microbial Communities in Alpine Soils: Seasonal and Elevational Effects

2015

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Microbial communities in alpine environments are exposed to several environmental factors related to elevation and local site conditions and to extreme seasonal variations. However, little is known on the combined impact of such factors on microbial community structure. We assessed the effects of seasonal variations on soil fungal and bacterial communities along an elevational gradient (from alpine meadows to a glacier forefield, 1930–2519 m a.s.l.) over 14 months. Samples were taken during all four seasons, even under the winter snowpack and at snowmelt. Microbial community structures and abundances were investigated using Terminal Restriction Fragment Length Polymorphism (T-RFLP) and quantitative PCR (qPCR) of the 16S and 18S rRNA genes. Illumina sequencing was performed to identify key bacterial groups in selected samples. We found that the soil properties varied significantly with the seasons and along the elevational gradient. For example, concentrations of soluble nutrients (e.g., NH4+-N, SO42−-S, PO43−-P) significantly increased in October but decreased drastically under the winter snowpack. At all times, the alpine meadows showed higher soluble nutrient concentrations than the glacier forefield. Microbial community structures at the different sites were strongly affected by seasonal variations. Under winter snowpack, bacterial communities were dominated by ubiquitous groups (i.e., beta-Proteobacteria, which made up to 25.7% of the total reads in the glacier forefield). In the snow-free seasons, other groups (i.e., Cyanobacteria) became more abundant (from 1% under winter snow in the glacier forefield samples to 8.1% in summer). In summary, elevation had a significant effect on soil properties, whereas season influenced soil properties as well as microbial community structure. Vegetation had a minor impact on microbial communities. At every elevation analyzed, bacterial, and fungal community structures exhibited a pronounced annual cycle.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 67%

Structures of Microbial Communities in Alpine Soils: Seasonal and Elevational Effects

2015

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“…Similar findings by Vestgarden and Austnes (2009) were attributed to soil micro-organisms from shallow snow sites being adapted to fluctuating winter temperatures. That microbial communities differ in composition along natural snow cover gradients (Zinger et al 2009, Shahnavaz et al 2012, and in general show a higher resistance to freezing-thawing processes in cold regions (Henry 2007, Matzner and has been shown in studies along steep environmental gradients. Our study system with a snow lie history that was modified due to the snow fence relatively recently suggests that the winter microbial community composition can adapt to changes in snow cover over much shorter time periods.…”

Section: Discussionmentioning

confidence: 92%

Snow cover, freeze‐thaw, and the retention of nutrients in an oceanic mountain ecosystem

et al. 2015

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As the climate warms, winters with less snow and therefore more soil freeze‐thaw cycles are likely to become more frequent in oceanic mountain areas. It is a concern that this might impair the soil's ability to store carbon and nutrients, and lead to increased leaching losses of dissolved C and nutrients and subsequent changes in nutrient cycling and ecosystem productivity. Through a combination of laboratory and field experiments, we studied short‐term effects of changing winter conditions on carbon and nutrient leaching from two plant‐soil systems with contrasting snow conditions (shallow/intermittent vs. deep/persistent snow). In the laboratory we exposed cores (soil and vegetation) from sites with either intermittent or persistent winter snow cover to five different freeze‐thaw scenarios of realistic frequency and duration. Additionally, we set up a transplant experiment at our field site by reciprocally transplanting soil‐plant monoliths between sites with intermittent and persistent snow. Together, the field and laboratory experiments aimed to assess how carbon and nutrient leaching was affected by both historical snow conditions and short‐term (through freeze‐thaw scenarios and transplantation) changes in snow cover and thermal conditions. Both a greater number of freeze‐thaw cycles and longer duration of sub‐zero temperatures increased carbon and nutrient leaching from incubated soil cores. Cores from sites with persistent snow generally had lower nutrient losses under control conditions, but greater losses following induced freeze‐thaw cycles than cores from intermittent snow sites. The character of the leached dissolved organic carbon (DOC) suggested fresh organic material, such as live plant roots or microbes, as the source of carbon and nutrients. Nutrient losses from the plant‐soil systems in the field were greater at sites with persistent winter snow due to greater volumes of percolating water in spring. This suggests that increasingly severe and frequent soil freeze‐thaw events in oceanic mountain ecosystems can enhance the mobilization of C, N and P in labile forms but, in the absence of water fluxes, these nutrients would remain available for in‐situ cycling. Thus, under future warmer winter conditions, increased carbon and nutrient losses from oceanic mountain ecosystems could occur if winters with little snow coincide with wet spring conditions.

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“…Although not examined in this study, seasonal fluctuations are another important driver of soil microbial community structure and relative abundance of taxa in alpine environments (Lazzaro et al., ). While elevation and vegetation type significantly affect abiotic soil properties, seasonal fluctuations in resources can be equally important predictors of microbial community composition (Lazzaro et al., ; Shahnavaz, Zinger, Lavergne, Choler, & Geremia, ). Further, bacteria and fungi respond very differently to seasonal events including snowpack, snowmelt and peak growing season (Lazzaro et al., ; Zinger et al., ).…”

Section: Discussionmentioning

confidence: 99%

Shrub range expansion alters diversity and distribution of soil fungal communities across an alpine elevation gradient

et al. 2018

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Global climate and land use change are altering plant and soil microbial communities worldwide, particularly in arctic and alpine biomes where warming is accelerated. The widespread expansion of woody shrubs into historically herbaceous alpine plant zones is likely to interact with climate to affect soil microbial community structure and function; however, our understanding of alpine soil ecology remains limited. This study aimed to (i) determine whether the diversity and community composition of soil fungi vary across elevation gradients and to (ii) assess the impact of woody shrub expansion on these patterns. In the White Mountains of California, sagebrush (Artemisia rothrockii) shrubs have been expanding upwards into alpine areas since 1960. In this study, we combined observational field data with a manipulative shrub removal experiment along an elevation transect of alpine shrub expansion. We utilized next-generation sequencing of the ITS1 region for fungi and joint distribution modelling to tease apart effects of the environment and intracommunity interactions on soil fungi. We found that soil fungal diversity declines and community composition changes with increasing elevation. Both abiotic factors (primarily soil moisture and soil organic C) and woody sagebrush range expansion had significant effects on these patterns. However, fungal diversity and relative abundance had high spatial variation, overwhelming the predictive power of vegetation type, elevation and abiotic soil conditions at the landscape scale. Finally, we observed positive and negative associations among fungal taxa which may be important in structuring community responses to global change.

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Phylogenetic Clustering Reveals Selective Events Driving the Turnover of Bacterial Community in Alpine Tundra Soils

Cited by 9 publications

References 33 publications

Structures of Microbial Communities in Alpine Soils: Seasonal and Elevational Effects

Structures of Microbial Communities in Alpine Soils: Seasonal and Elevational Effects

Snow cover, freeze‐thaw, and the retention of nutrients in an oceanic mountain ecosystem

Shrub range expansion alters diversity and distribution of soil fungal communities across an alpine elevation gradient

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