Nitrogen transport in a tundra landscape : the effects of early and late growing season lateral N inputs on arctic soil and plant N pools and N2O fluxes
Rasmussen, Laura H. ; Zhang, Wenxin LU
; Ambus, Per
; Michelsen, Anders
; Jansson, Per Erik
; Kitzler, Barbara
and Elberling, Bo
(2022)
In Biogeochemistry
157(1).
p.69-84
- Abstract
Understanding N budgets of tundra ecosystems is crucial for projecting future changes in plant community composition, greenhouse gas balances and soil N stocks. Winter warming can lead to higher tundra winter nitrogen (N) mineralization rates, while summer warming may increase both growing season N mineralization and plant N demand. The undulating tundra landscape is inter-connected through water and solute movement on top of and within near-surface soil, but the importance of lateral N fluxes for tundra N budgets is not well known. We studied the size of lateral N fluxes and the fate of lateral N input in the snowmelt period with a shallow thaw layer, and in the late growing season with a deeper thaw layer. We used 15N to... (More)
Understanding N budgets of tundra ecosystems is crucial for projecting future changes in plant community composition, greenhouse gas balances and soil N stocks. Winter warming can lead to higher tundra winter nitrogen (N) mineralization rates, while summer warming may increase both growing season N mineralization and plant N demand. The undulating tundra landscape is inter-connected through water and solute movement on top of and within near-surface soil, but the importance of lateral N fluxes for tundra N budgets is not well known. We studied the size of lateral N fluxes and the fate of lateral N input in the snowmelt period with a shallow thaw layer, and in the late growing season with a deeper thaw layer. We used 15N to trace inorganic lateral N movement in a Low-arctic mesic tundra heath slope in West Greenland and to quantify the fate of N in the receiving area. We found that half of the early-season lateral N input was retained by the receiving ecosystem, whereas half was transported downslope. Plants appear as poor utilizers of early-season N, indicating that higher winter N mineralization may influence plant growth and carbon (C) sequestration less than expected. Still, evergreen plants were better at utilizing early-season N, highlighting how changes in N availability may impact plant community composition. In contrast, later growing season lateral N input was deeper and offered an advantage to deeper-rooted deciduous plants. The measurements suggest that N input driven by future warming at the study site will have no significant impact on the overall N2O emissions. Our work underlines how tundra ecosystem N allocation, C budgets and plant community composition vary in their response to lateral N inputs, which may help us understand future responses in a warmer Arctic.
(Less)
- author
- Rasmussen, Laura H.
; Zhang, Wenxin
LU
; Ambus, Per
; Michelsen, Anders
; Jansson, Per Erik
; Kitzler, Barbara
and Elberling, Bo
- organization
- publishing date
- 2022
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Arctic tundra, Climate change, Nitrate, Solute transport, Winter N mineralization
- in
- Biogeochemistry
- volume
- 157
- issue
- 1
- pages
- 16 pages
- publisher
- Springer
- external identifiers
-
- scopus:85117256432
- ISSN
- 0168-2563
- DOI
- 10.1007/s10533-021-00855-y
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
- id
- 3401d381-fbbe-4a7e-a480-70cb474751d0
- date added to LUP
- 2021-10-26 14:28:37
- date last changed
- 2022-04-27 05:16:10
@article{3401d381-fbbe-4a7e-a480-70cb474751d0,
abstract = {{<p>Understanding N budgets of tundra ecosystems is crucial for projecting future changes in plant community composition, greenhouse gas balances and soil N stocks. Winter warming can lead to higher tundra winter nitrogen (N) mineralization rates, while summer warming may increase both growing season N mineralization and plant N demand. The undulating tundra landscape is inter-connected through water and solute movement on top of and within near-surface soil, but the importance of lateral N fluxes for tundra N budgets is not well known. We studied the size of lateral N fluxes and the fate of lateral N input in the snowmelt period with a shallow thaw layer, and in the late growing season with a deeper thaw layer. We used <sup>15</sup>N to trace inorganic lateral N movement in a Low-arctic mesic tundra heath slope in West Greenland and to quantify the fate of N in the receiving area. We found that half of the early-season lateral N input was retained by the receiving ecosystem, whereas half was transported downslope. Plants appear as poor utilizers of early-season N, indicating that higher winter N mineralization may influence plant growth and carbon (C) sequestration less than expected. Still, evergreen plants were better at utilizing early-season N, highlighting how changes in N availability may impact plant community composition. In contrast, later growing season lateral N input was deeper and offered an advantage to deeper-rooted deciduous plants. The measurements suggest that N input driven by future warming at the study site will have no significant impact on the overall N<sub>2</sub>O emissions. Our work underlines how tundra ecosystem N allocation, C budgets and plant community composition vary in their response to lateral N inputs, which may help us understand future responses in a warmer Arctic.</p>}},
author = {{Rasmussen, Laura H. and Zhang, Wenxin and Ambus, Per and Michelsen, Anders and Jansson, Per Erik and Kitzler, Barbara and Elberling, Bo}},
issn = {{0168-2563}},
keywords = {{Arctic tundra; Climate change; Nitrate; Solute transport; Winter N mineralization}},
language = {{eng}},
number = {{1}},
pages = {{69--84}},
publisher = {{Springer}},
series = {{Biogeochemistry}},
title = {{Nitrogen transport in a tundra landscape : the effects of early and late growing season lateral N inputs on arctic soil and plant N pools and N<sub>2</sub>O fluxes}},
url = {{http://dx.doi.org/10.1007/s10533-021-00855-y}},
doi = {{10.1007/s10533-021-00855-y}},
volume = {{157}},
year = {{2022}},
}