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The responses of moss-associated nitrogen fixation and belowground microbial community to chronic Mo and P supplements in subarctic dry heaths

Rousk, Kathrin LU and Rousk, Johannes LU (2020) In Plant and Soil 451(1-2). p.261-276
Abstract

Aims: Although nitrogen (N) fixation by moss-associated bacteria is the main source of new N in N-limited ecosystems like arctic tundra, we do not know which nutrient, molybdenum (Mo) or phosphorus (P), is rate-limiting for sustaining this process in the long-term. Further, how moss-associated N2 fixation impacts the belowground microbial regulation of decomposition remains unresolved. Methods: Moss-associated N2 fixation and soil microbial process rates, abundance and community structure were assessed in long-term P and Mo field additions in the Subarctic during three years. Results: We found tendencies for stimulation of moss-associated N2 fixation by Mo in the short term, by P in the long-term, and... (More)

Aims: Although nitrogen (N) fixation by moss-associated bacteria is the main source of new N in N-limited ecosystems like arctic tundra, we do not know which nutrient, molybdenum (Mo) or phosphorus (P), is rate-limiting for sustaining this process in the long-term. Further, how moss-associated N2 fixation impacts the belowground microbial regulation of decomposition remains unresolved. Methods: Moss-associated N2 fixation and soil microbial process rates, abundance and community structure were assessed in long-term P and Mo field additions in the Subarctic during three years. Results: We found tendencies for stimulation of moss-associated N2 fixation by Mo in the short term, by P in the long-term, and tendencies for a stimulation of soil microbial activity by P. However, large variation in microbial activity within and below the moss exceeded any systematic variation induced by the field treatments. Our findings suggest that soil microbial activity is not limited by N at our site, and that Mo and P only occasionally limit N2 fixation during a growing season. Conclusions: Since increasing CO2 concentrations can induce nutrient limitation, the here reported transient limitation can easily shift into a chronic one with significant implications for ecosystem productivity and biogeochemistry.

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type
Contribution to journal
publication status
published
subject
keywords
Bryophytes, Cyanobacteria, Nitrogen fixation, Nutrient limitation, Soil fungal and bacterial growth
in
Plant and Soil
volume
451
issue
1-2
pages
16 pages
publisher
Springer
external identifiers
  • scopus:85084667584
ISSN
0032-079X
DOI
10.1007/s11104-020-04492-6
language
English
LU publication?
yes
id
b187a4b4-f33e-40e0-96eb-1ff27045d7c5
date added to LUP
2020-06-15 10:56:57
date last changed
2020-12-02 13:23:58
@article{b187a4b4-f33e-40e0-96eb-1ff27045d7c5,
  abstract     = {<p>Aims: Although nitrogen (N) fixation by moss-associated bacteria is the main source of new N in N-limited ecosystems like arctic tundra, we do not know which nutrient, molybdenum (Mo) or phosphorus (P), is rate-limiting for sustaining this process in the long-term. Further, how moss-associated N<sub>2</sub> fixation impacts the belowground microbial regulation of decomposition remains unresolved. Methods: Moss-associated N<sub>2</sub> fixation and soil microbial process rates, abundance and community structure were assessed in long-term P and Mo field additions in the Subarctic during three years. Results: We found tendencies for stimulation of moss-associated N<sub>2</sub> fixation by Mo in the short term, by P in the long-term, and tendencies for a stimulation of soil microbial activity by P. However, large variation in microbial activity within and below the moss exceeded any systematic variation induced by the field treatments. Our findings suggest that soil microbial activity is not limited by N at our site, and that Mo and P only occasionally limit N<sub>2</sub> fixation during a growing season. Conclusions: Since increasing CO<sub>2</sub> concentrations can induce nutrient limitation, the here reported transient limitation can easily shift into a chronic one with significant implications for ecosystem productivity and biogeochemistry.</p>},
  author       = {Rousk, Kathrin and Rousk, Johannes},
  issn         = {0032-079X},
  language     = {eng},
  number       = {1-2},
  pages        = {261--276},
  publisher    = {Springer},
  series       = {Plant and Soil},
  title        = {The responses of moss-associated nitrogen fixation and belowground microbial community to chronic Mo and P supplements in subarctic dry heaths},
  url          = {http://dx.doi.org/10.1007/s11104-020-04492-6},
  doi          = {10.1007/s11104-020-04492-6},
  volume       = {451},
  year         = {2020},
}