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Research article - Peer-reviewed, 2021

Site-specific responses of fungal and bacterial abundances to experimental warming in litter and soil across arctic and alpine tundra

Hallin, Sara; Jeanbille, Mathilde; Engelbrecht Clemmensen, Karina; Juhanson, Jaanis; Michelsen, Anders; Cooper, Elisabeth J.; Henry, Greg H.R.; Hofgaard, Annika; Hollister, Robert D.; Jónsdóttir, Ingibjörg S.; Klanderud, Kari; Tolvanen, Anne

Abstract

Vegetation change of the Arctic tundra due to global warming is a well-known process, but the implication for the belowground microbial communities, key in nutrient cycling and decomposition, is poorly understood. We characterized the fungal and bacterial abundances in litter and soil layers across 16 warming experimental sites at 12 circumpolar locations. We investigated the relationship between microbial abundances and nitrogen (N) and carbon (C) isotopic signatures, indicating shifts in microbial processes with warming. Microbial abundances were 2–3 orders of magnitude larger in litter than in soil. Local, site-dependent responses of microbial abundances were variable, and no general effect of warming was detected. The only generalizable trend across sites was a dependence between the warming response ratios and C:N ratio in controls, highlighting a legacy of the vegetation on the microbial response to warming. We detected a positive effect of warming on the litter mass and δ15N, which was linked to bacterial abundance under warmed conditions. This effect was stronger in experimental sites dominated by deciduous shrubs, suggesting an altered bacterial N-cycling with increased temperatures, mediated by the vegetation, and with possible consequences on ecosystem feedbacks to climate change.

Keywords

tundra; warming; litter; soil; microbial abundance; stable isotopes

Published in

Arctic science
2021,

Authors' information

Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Jeanbille, Mathilde
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Michelsen, Anders
University of Copenhagen
Cooper, Elisabeth J.
University of Tromso, the Arctic University of Norway (UiT)
Henry, Greg H.R.
University of British Columbia
Hofgaard, Annika
Norwegian Institute for Nature Research (NINA)
Hollister, Robert D.
Grand Valley State University
Jónsdóttir, Ingibjörg S.
University of Iceland
Klanderud, Kari
Norwegian University of Life Sciences
Tolvanen, Anne
Natural Resources Institute Finland (LUKE)

UKÄ Subject classification

Soil Science

Publication Identifiers

DOI: https://doi.org/10.1139/as-2020-0053

URI (permanent link to this page)

https://res.slu.se/id/publ/115606