Premium
Nitrogen cycling and feedbacks in a global dynamic land model
Author(s) -
Gerber Stefan,
Hedin Lars O.,
Oppenheimer Michael,
Pacala Stephen W.,
Shevliakova Elena
Publication year - 2010
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2008gb003336
Subject(s) - cycling , environmental science , ecosystem , carbon cycle , nitrogen cycle , disturbance (geology) , ecosystem model , productivity , atmospheric sciences , greenhouse gas , terrestrial ecosystem , global change , climate change , carbon sequestration , nitrogen , primary production , ecology , carbon fibers , carbon dioxide , chemistry , computer science , biology , geology , history , paleontology , macroeconomics , archaeology , organic chemistry , algorithm , composite number , economics
Global anthropogenic changes in carbon (C) and nitrogen (N) cycles call for modeling tools that are able to address and quantify essential interactions between N, C, and climate in terrestrial ecosystems. Here we introduce a prognostic N cycle within the Princeton–Geophysical Fluid Dynamic Laboratory (GFDL) LM3V land model. The model captures mechanisms essential for N cycling and their feedbacks on C cycling: N limitation of plant productivity, the N dependence of C decomposition and stabilization in soils, removal of available N by competing sinks, ecosystem losses that include dissolved organic and volatile N, and ecosystem inputs through biological N fixation. Our model captures many essential characteristics of C‐N interactions and is capable of broadly recreating spatial and temporal variations in N and C dynamics. The introduced N dynamics improve the model's short‐term NPP response to step changes in CO 2 . Consistent with theories of successional dynamics, we find that physical disturbance induces strong C‐N feedbacks, caused by intermittent N loss and subsequent N limitation. In contrast, C‐N interactions are weak when the coupled model system approaches equilibrium. Thus, at steady state, many simulated features of the carbon cycle, such as primary productivity and carbon inventories, are similar to simulations that do not include C‐N feedbacks.