DOI: 10.1111/gcb.12813
论文题名: Nitrogen limitation on land: How can it occur in Earth system models?
作者: Thomas R.Q. ; Brookshire E.N.J. ; Gerber S.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2015
卷: 21, 期: 5 起始页码: 1777
结束页码: 1793
语种: 英语
英文关键词: Biogeochemical modeling
; Carbon cycle
; Carbon-climate feedbacks
; Climate change
; Global biogeochemical models
; Land-surface models
; Model evaluation
; Terrestrial ecosystems modeling
Scopus关键词: biogeochemistry
; carbon cycle
; climate change
; climate feedback
; global change
; land surface
; nitrogen cycle
; terrestrial ecosystem
; nitrogen
; soil
; astronomy
; carbon sequestration
; chemistry
; ecosystem
; metabolism
; nitrogen cycle
; physiology
; soil
; theoretical model
; Carbon Sequestration
; Earth (Planet)
; Ecosystem
; Models, Theoretical
; Nitrogen
; Nitrogen Cycle
; Soil
英文摘要: The representation of the nitrogen (N) cycle in Earth system models (ESMs) is strongly motivated by the constraint N poses on the sequestration of anthropogenic carbon (C). Models typically implement a stoichiometric relationship between C and N in which external supply and assimilation by organisms are adjusted to maintain their internal stoichiometry. N limitation of primary productivity thus occurs if the N supply from uptake and fixation cannot keep up with the construction of tissues allowed by C assimilation. This basic approach, however, presents considerable challenges in how to faithfully represent N limitation. Here, we review how N limitation is currently implemented and evaluated in ESMs and highlight challenges and opportunities in their future development. At or near steady state, N limitation is governed by the magnitude of losses from the plant-unavailable pool vs. N fixation and there are considerable differences in how models treat both processes. In nonsteady-state systems, the accumulation of N in pools with slow turnover rates reduces N available for plant uptake and can be challenging to represent when initializing ESM simulations. Transactional N limitation occurs when N is incorporated into various vegetation and soil pools and becomes available to plants only after it is mineralized, the dynamics of which depends on how ESMs represent decomposition processes in soils. Other challenges for ESMs emerge when considering seasonal to interannual climatic oscillations as they create asynchronies between C and N demand, leading to transient alternations between N surplus and deficit. Proper evaluation of N dynamics in ESMs requires conceptual understanding of the main levers that trigger N limitation, and we highlight key measurements and observations that can help constrain these levers. Two of the biggest challenges are the mechanistic representation of plant controls on N availability and turnover, including N fixation and organic matter decomposition processes. © 2015 John Wiley & Sons Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/61874
Appears in Collections: 影响、适应和脆弱性
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作者单位: Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA, United States; Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, United States; Soil and Water Science Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States
Recommended Citation:
Thomas R.Q.,Brookshire E.N.J.,Gerber S.. Nitrogen limitation on land: How can it occur in Earth system models?[J]. Global Change Biology,2015-01-01,21(5)