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Spatiotemporal Assessment of GHG Emissions and Nutrient Sequestration Linked to Agronutrient Runoff in Global Wetlands
Author(s) -
Pasut Chiara,
Tang Fiona H. M.,
Hamilton David,
Riley William J.,
Maggi Federico
Publication year - 2021
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 - 10.1029/2020gb006816
Subject(s) - wetland , environmental science , greenhouse gas , nutrient , carbon sequestration , surface runoff , hydrology (agriculture) , carbon dioxide , ecology , geotechnical engineering , engineering , biology
Wetlands play a key role in regulating global greenhouse gas (GHG) emissions but anthropogenic impacts on nutrients may severely alter this balance. Recent assessments indicate that almost 22% of the global wetland area may be affected by agricultural runoff. In this work, we developed and applied a dynamic mechanistic reaction network model of soil organic matter linking the carbon (C), nitrogen (N), and sulfur (S) cycles at 0.5° × 0.5° spatial resolution across the globe. The model was used to estimate GHG emissions and nutrient sequestration rates in wetlands, driven by environmental stressors including N, P, and S fertilization. Wetland annual GHG emissions are estimated to be 136 ± 12.5 Tg C‐CH 4 , 589 ± 45.8 Tg C‐CO 2 , and 0.3 ± 0.04 Tg N‐N 2 O; in contrast, C, N, and S annual sequestration rates are estimated to be 576 ± 88.1 Tg C, 20 ± 4.4 Tg N, and 7.4 ± 0.8 Tg S, between 2000 and 2017. N fertilization inputs were responsible for 13% N 2 O emissions in wetlands in the Northern Hemisphere, while tropical wetlands were major reservoirs for C, N, and S. Temperature, net primary productivity, and methanogenic microorganisms exert the major control on GHG emissions. Wetland CH 4 and CO 2 emissions were found to have a hysteretic relationship with seasonal soil temperature, but not N 2 O. A global‐scale assessment is pivotal for best nutrient management practices, reducing nutrient losses, and controlling gas emissions.