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Soil microbial resource limitation along a subarctic ecotone from birch forest to tundra heath

Neurauter, Markus ; Yuan, Mingyue LU ; Hicks, Lettice LU and Rousk, Johannes LU (2023) In Soil Biology & Biochemistry 177.
Abstract
Soil microorganisms regulate the decomposition of organic matter. However, microbial activities can also be rate-limited by the resource in lowest supply. Arctic ecosystems are being exposed to pronounced climate warming, with arctic greening, treeline advance and shrubification resulting in increased plant-derived carbon (C) inputs to soils, and faster rates of decomposition releasing mineral nutrients, potentially shifting the limiting factor for microbial growth. Here we used a “space-for-time” approach across a subarctic ecotone (birch forest, tree line, shrub and tundra sites). N and P fertilization treatments were also applied in the field, to test whether changes in resource limitation could be induced through nutrient loading of... (More)
Soil microorganisms regulate the decomposition of organic matter. However, microbial activities can also be rate-limited by the resource in lowest supply. Arctic ecosystems are being exposed to pronounced climate warming, with arctic greening, treeline advance and shrubification resulting in increased plant-derived carbon (C) inputs to soils, and faster rates of decomposition releasing mineral nutrients, potentially shifting the limiting factor for microbial growth. Here we used a “space-for-time” approach across a subarctic ecotone (birch forest, tree line, shrub and tundra sites). N and P fertilization treatments were also applied in the field, to test whether changes in resource limitation could be induced through nutrient loading of soils. In these soils, we measured the responses of bacterial and fungal growth as well as soil respiration to full factorial additions of C, nitrogen (N) and phosphorus (P) (“limiting factor assays”: LFA) to infer how the limiting factor for microbial growth would be affected by future climate change. We found that bacteria were triple-limited by C, N and P, while fungi were co-limited by C and N, with no shift in the limiting factor for bacterial or fungal growth across the ecotone. However, bacterial responses to the LFA were stronger in the tundra, showing 9-fold stronger increases in response to LFA-CNP addition compared to that in the forest. In contrast, fungal responses to the LFA were stronger in the forest, showing a 120% higher growth in response to LFA-CN addition, with no detectable response to LFA-CN addition in the tundra. These contrasting results suggested competitive interactions for resources between the two decomposer groups. Fertilization in the field shifted the bacterial resource limitation, but had no effect on the limiting factor for fungal growth. Together, our findings suggest that resource limitations for soil microorganisms will not change due to future warming, but rather affect degrees of fungal-to-bacterial dominance. (Less)
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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Soil Biology & Biochemistry
volume
177
article number
108919
pages
12 pages
publisher
Elsevier
external identifiers
  • scopus:85144345858
ISSN
0038-0717
DOI
10.1016/j.soilbio.2022.108919
language
English
LU publication?
yes
id
558d9396-9310-44b9-96c6-fc338278cc45
date added to LUP
2022-12-26 07:43:12
date last changed
2024-05-16 12:21:24
@article{558d9396-9310-44b9-96c6-fc338278cc45,
  abstract     = {{Soil microorganisms regulate the decomposition of organic matter. However, microbial activities can also be rate-limited by the resource in lowest supply. Arctic ecosystems are being exposed to pronounced climate warming, with arctic greening, treeline advance and shrubification resulting in increased plant-derived carbon (C) inputs to soils, and faster rates of decomposition releasing mineral nutrients, potentially shifting the limiting factor for microbial growth. Here we used a “space-for-time” approach across a subarctic ecotone (birch forest, tree line, shrub and tundra sites). N and P fertilization treatments were also applied in the field, to test whether changes in resource limitation could be induced through nutrient loading of soils. In these soils, we measured the responses of bacterial and fungal growth as well as soil respiration to full factorial additions of C, nitrogen (N) and phosphorus (P) (“limiting factor assays”: LFA) to infer how the limiting factor for microbial growth would be affected by future climate change. We found that bacteria were triple-limited by C, N and P, while fungi were co-limited by C and N, with no shift in the limiting factor for bacterial or fungal growth across the ecotone. However, bacterial responses to the LFA were stronger in the tundra, showing 9-fold stronger increases in response to LFA-CNP addition compared to that in the forest. In contrast, fungal responses to the LFA were stronger in the forest, showing a 120% higher growth in response to LFA-CN addition, with no detectable response to LFA-CN addition in the tundra. These contrasting results suggested competitive interactions for resources between the two decomposer groups. Fertilization in the field shifted the bacterial resource limitation, but had no effect on the limiting factor for fungal growth. Together, our findings suggest that resource limitations for soil microorganisms will not change due to future warming, but rather affect degrees of fungal-to-bacterial dominance.}},
  author       = {{Neurauter, Markus and Yuan, Mingyue and Hicks, Lettice and Rousk, Johannes}},
  issn         = {{0038-0717}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Soil Biology & Biochemistry}},
  title        = {{Soil microbial resource limitation along a subarctic ecotone from birch forest to tundra heath}},
  url          = {{http://dx.doi.org/10.1016/j.soilbio.2022.108919}},
  doi          = {{10.1016/j.soilbio.2022.108919}},
  volume       = {{177}},
  year         = {{2023}},
}