2018
Murguia-Flores, Fabiola; Arndt, Sandra; Ganesan, Anita L; Murray-Tortarolo, Guillermo; Hornibrook, Edward R C
Soil Methanotrophy Model (MeMo v1.0): A process-based model to quantify global uptake of atmospheric methane by soil Journal Article
In: Geoscientific Model Development, vol. 11, no. 6, pp. 2009–2032, 2018, ISSN: 19919603.
Abstract | Links | BibTeX | Tags: metanotrophy, methane
@article{Murguia-Flores2018,
title = {Soil Methanotrophy Model (MeMo v1.0): A process-based model to quantify global uptake of atmospheric methane by soil},
author = {Fabiola Murguia-Flores and Sandra Arndt and Anita L Ganesan and Guillermo Murray-Tortarolo and Edward R C Hornibrook},
doi = {10.5194/gmd-11-2009-2018},
issn = {19919603},
year = {2018},
date = {2018-01-01},
journal = {Geoscientific Model Development},
volume = {11},
number = {6},
pages = {2009--2032},
abstract = {Soil bacteria known as methanotrophs are the sole biological sink for atmospheric methane (CHtextlesssubtextgreater4textless/subtextgreater), a powerful greenhouse gas that is responsible for ~ 20 % of the human-driven increase in radiative forcing since pre-industrial times. Soil methanotrophy is controlled by a plethora of different factors, including temperature, soil texture and moisture or nitrogen content, resulting in spatially and temporally heterogeneous rates of soil methanotrophy. As a consequence, the exact magnitude of the global soil sink, as well as its temporal and spatial variability remains poorly constrained. We developed a process-based model (Methanotrophy Model; MeMo v1.0) to simulate and quantify the uptake of atmospheric CHtextlesssubtextgreater4textless/subtextgreater by soils on the global scale. MeMo builds on previous models by Ridgwell et al. (1999) and Curry (2007) by introducing several advances, including: (1) a general analytical solution of the one-dimensional diffusion-reaction equation in porous media, (2) a refined representation of nitrogen inhibition on soil methanotrophy, and (3) updated factors governing the influence of soil moisture and temperature on CHtextlesssubtextgreater4textless/subtextgreater oxidation rates. We show that the improved representation of these key drivers of soil methanotrophy resulted in a better fit to observational data. A global simulation of soil methanotrophy for the period 1990-2009 using MeMo yielded an average annual sink of 34.3 ± 4.3 Tg CHtextlesssubtextgreater4textless/subtextgreater yrtextlesssuptextgreater−1textless/suptextgreater. Warm and semiarid regions (tropical deciduous forest, dense and open shrubland) had the highest CHtextlesssubtextgreater4textless/subtextgreater uptake rates of 630 and 580 mg CHtextlesssubtextgreater4textless/subtextgreater mtextlesssuptextgreater−2textless/suptextgreater ytextlesssuptextgreater−1textless/suptextgreater, respectively. In these regions, favorable annual soil moisture content (~ 20 % saturation) and low seasonal temperature variations (variations textless ~ 6 textordmasculineC) provided optimal conditions for soil methanotrophy and soil-atmosphere gas exchange. In contrast to previous model analyses, but in agreement with recent observational data, MeMo predicted low fluxes in wet tropical regions because of refinements in describing the influence of excess soil moisture on methanotrophy. Tundra and boreal forest had the lowest simulated CHtextlesssubtextgreater4textless/subtextgreater uptake rates of 179 and 187 mg CHtextlesssubtextgreater4textless/subtextgreater mtextlesssuptextgreater−2textless/suptextgreater ytextlesssuptextgreater−1textless/suptextgreater, respectively, due to their marked seasonality driven by temperature. Soil uptake of atmospheric CHtextlesssubtextgreater4textless/subtextgreater was attenuated by up to 10 % in regions receiving high rates of nitrogen deposition. Globally, nitrogen deposition reduced soil uptake of atmospheric CHtextlesssubtextgreater4textless/subtextgreater by 0.34 Tg ytextlesssuptextgreater−1textless/suptextgreater, which is an order of magnitude lower than reported previously. In addition to improved characterisation of the contemporary soil sink for atmospheric CHtextlesssubtextgreater4textless/subtextgreater, MeMo provides an opportunity to quantify more accurately the relative importance of soil methanotrophy in the global CHtextlesssubtextgreater4textless/subtextgreater cycle in the past and its capacity to contribute to reduction of atmospheric CHtextlesssubtextgreater4textless/subtextgreater levels under future global change scenarios.},
keywords = {metanotrophy, methane},
pubstate = {published},
tppubtype = {article}
}
Soil bacteria known as methanotrophs are the sole biological sink for atmospheric methane (CHtextlesssubtextgreater4textless/subtextgreater), a powerful greenhouse gas that is responsible for ~ 20 % of the human-driven increase in radiative forcing since pre-industrial times. Soil methanotrophy is controlled by a plethora of different factors, including temperature, soil texture and moisture or nitrogen content, resulting in spatially and temporally heterogeneous rates of soil methanotrophy. As a consequence, the exact magnitude of the global soil sink, as well as its temporal and spatial variability remains poorly constrained. We developed a process-based model (Methanotrophy Model; MeMo v1.0) to simulate and quantify the uptake of atmospheric CHtextlesssubtextgreater4textless/subtextgreater by soils on the global scale. MeMo builds on previous models by Ridgwell et al. (1999) and Curry (2007) by introducing several advances, including: (1) a general analytical solution of the one-dimensional diffusion-reaction equation in porous media, (2) a refined representation of nitrogen inhibition on soil methanotrophy, and (3) updated factors governing the influence of soil moisture and temperature on CHtextlesssubtextgreater4textless/subtextgreater oxidation rates. We show that the improved representation of these key drivers of soil methanotrophy resulted in a better fit to observational data. A global simulation of soil methanotrophy for the period 1990–2009 using MeMo yielded an average annual sink of 34.3 ± 4.3 Tg CHtextlesssubtextgreater4textless/subtextgreater yrtextlesssuptextgreater−1textless/suptextgreater. Warm and semiarid regions (tropical deciduous forest, dense and open shrubland) had the highest CHtextlesssubtextgreater4textless/subtextgreater uptake rates of 630 and 580 mg CHtextlesssubtextgreater4textless/subtextgreater mtextlesssuptextgreater−2textless/suptextgreater ytextlesssuptextgreater−1textless/suptextgreater, respectively. In these regions, favorable annual soil moisture content (~ 20 % saturation) and low seasonal temperature variations (variations textless ~ 6 textordmasculineC) provided optimal conditions for soil methanotrophy and soil-atmosphere gas exchange. In contrast to previous model analyses, but in agreement with recent observational data, MeMo predicted low fluxes in wet tropical regions because of refinements in describing the influence of excess soil moisture on methanotrophy. Tundra and boreal forest had the lowest simulated CHtextlesssubtextgreater4textless/subtextgreater uptake rates of 179 and 187 mg CHtextlesssubtextgreater4textless/subtextgreater mtextlesssuptextgreater−2textless/suptextgreater ytextlesssuptextgreater−1textless/suptextgreater, respectively, due to their marked seasonality driven by temperature. Soil uptake of atmospheric CHtextlesssubtextgreater4textless/subtextgreater was attenuated by up to 10 % in regions receiving high rates of nitrogen deposition. Globally, nitrogen deposition reduced soil uptake of atmospheric CHtextlesssubtextgreater4textless/subtextgreater by 0.34 Tg ytextlesssuptextgreater−1textless/suptextgreater, which is an order of magnitude lower than reported previously. In addition to improved characterisation of the contemporary soil sink for atmospheric CHtextlesssubtextgreater4textless/subtextgreater, MeMo provides an opportunity to quantify more accurately the relative importance of soil methanotrophy in the global CHtextlesssubtextgreater4textless/subtextgreater cycle in the past and its capacity to contribute to reduction of atmospheric CHtextlesssubtextgreater4textless/subtextgreater levels under future global change scenarios.
