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oai:www.ideals.illinois.edu:2142/85977 2023-07-11 col_2142_5131 col_2142_14839 com_2142_5130 com_2142_14838 com_2142_13459 com_2142_8903

Atul Jain Yang, Xiaojuan 2015-09-28T14:52:25Z 2015-09-28T14:52:25Z 10000-01-01 2009 2009 In the second part of this thesis, a comprehensive model of terrestrial nitrogen (N) dynamics is developed and coupled with the geographically explicit terrestrial C cycle model of ISAM. Observations from the Long-term Intersite Decomposition Experiment (LIDET) dataset were compiled for the calibration and validation of the decomposition submodel. The terrestrial C-N cycle model was then used to evaluate how the introduction of N dynamics and interactions between C, N and climate influences terrestrial C sources and sinks in response to changes over the 20th century in global environmental factors including atmospheric CO2 concentrations, N deposition, climate and land use. This study shows (i) The terrestrial C sink from CO2 fertilization effect is reduced due to the limitation of N (by 0.53GtC/yr in the 1990s), (ii) the positive feedback between climate warming and terrestrial C cycle is attenuated due to the interactions between C, N and climate (by 0.34 GtC/yr in the 1990s), (iii) an enhanced terrestrial sink associated with N deposition (of 0.26 GtC/yr in the 1990s) and (iv) an enhanced source associated with changes in land use due to N limitation (of 0.08 GtC/yr in the 1990s). This study also suggests that the C sink associated with increasing atmospheric CO2 in subtropics is overestimated and the C source associated with changes in temperature and precipitation in higher latitude regions is underestimated when terrestrial N dynamics are not considered. This study highlights the importance of including the N dynamics when assessing terrestrial C sources and sinks with coupled C-climate system models. Made available in DSpace on 2015-09-28T14:52:25Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3363120.pdf: 3139244 bytes, checksum: 58b64f8fcf643f600a05bad6492e9866 (MD5) Previous issue date: 2009 Embargo set by: Seth Robbins for item 87258 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 151 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009. http://hdl.handle.net/2142/85977 (MiAaPQ)AAI3363120 eng Biogeochemistry Examining the Role of Climate, Carbon and Nitrogen Interactions in the Terrestrial Biosphere text Atmospheric Sciences Atmospheric Sciences University of Illinois at Urbana-Champaign Dissertation Ph.D.