Mineral properties, microbes, transport, and plant-input profiles control vertical distribution and age of soil carbon stocks

Dwivedi, Dipankar; Riley, William J.; Torn, M. S.; Spycher, Nicolas; Maggi, Federico; Tang, Jinyun

doi:10.1016/j.soilbio.2016.12.019

Cited by 75 publications

(76 citation statements)

References 114 publications

(37 reference statements)

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“…In many cases it adjoins the meandering river floodplain from the Holocene climatic optimum. Many examples supported by literature also indicate that fluvial processes have a direct impact on biogeochemical dynamics [6][7][8].…”

Section: Introductionmentioning

confidence: 88%

Morphogenesis of a Floodplain as a Criterion for Assessing the Susceptibility to Water Pollution in an Agriculturally Rich Valley of a Lowland River

Sieczka

Bujakowski

Falkowski

et al. 2018

Water

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This study presents the results of the influence of the specific geological landforms occurring in a lowland river floodplain on the recharge and drainage conditions in an agricultural area. Particular attention has been paid to the presence of the buried erosional channels of flood waters, which may constitute the preferential paths for migration of agricultural contaminants. Moreover, the changes of effective infiltration which affect the hydrogeological regime of the tested area were analyzed. Priority was also given to the use of laboratory techniques in order to determine the parameters influencing the contaminant migration in the soil-water environment for the purpose of hydrogeological modeling. Laboratory tests, based on a column experiment, were performed in a Trautwein apparatus with reference to the constant head procedure, using conservative and reactive markers. The parameters of advection, dispersion, and sorption, obtained in the laboratory experiment were then used as the input data for the hydrodynamic model of groundwater flow and contaminant migration in the research area. Based on the created digital model of groundwater flow, the multi-variant analysis of the effect of specific geological features on the conditions of contaminant transport in a valley was performed. The presented tools and methods contributed to a significant increase in the accuracy of recognizing zones susceptible to water pollution and should be adopted in other valley areas exposed to contamination.

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Section: Introductionmentioning

confidence: 88%

Morphogenesis of a Floodplain as a Criterion for Assessing the Susceptibility to Water Pollution in an Agriculturally Rich Valley of a Lowland River

Sieczka

Bujakowski

Falkowski

et al. 2018

Water

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“…On the other hand, because soil microbial activity in deep layers is limited by fresh and labile substrates, the input of fresh DOC may stimulate SOC decomposition in deep soils (Fontaine et al, 2007;Rumpel and Kogel-Knabner, 2011). Therefore, besides transport in the soil column by advection and diffusion, two main processes control DOC dynamics: (1) biological production and consumption and (2) adsorption to and desorption from soil minerals, and these processes in turn impact SOC cycling along the soil profile (Dwivedi et al, 2017;Kaiser and Kalbitz, 2012).…”

Section: Introductionmentioning

confidence: 99%

ORCHIDEE-SOM: modeling soil organic carbon (SOC) and dissolved organic carbon (DOC) dynamics along vertical soil profiles in Europe

et al. 2018

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Abstract. Current land surface models (LSMs) typically represent soils in a very simplistic way, assuming soil organic carbon (SOC) as a bulk, and thus impeding a correct representation of deep soil carbon dynamics. Moreover, LSMs generally neglect the production and export of dissolved organic carbon (DOC) from soils to rivers, leading to overestimations of the potential carbon sequestration on land. This common oversimplified processing of SOC in LSMs is partly responsible for the large uncertainty in the predictions of the soil carbon response to climate change. In this study, we present a new soil carbon module called ORCHIDEE-SOM, embedded within the land surface model ORCHIDEE, which is able to reproduce the DOC and SOC dynamics in a vertically discretized soil to 2 m. The model includes processes of biological production and consumption of SOC and DOC, DOC adsorption on and desorption from soil minerals, diffusion of SOC and DOC, and DOC transport with water through and out of the soils to rivers. We evaluated ORCHIDEE-SOM against observations of DOC concentrations and SOC stocks from four European sites with different vegetation covers: a coniferous forest, a deciduous forest, a grassland, and a cropland. The model was able to reproduce the SOC stocks along their vertical profiles at the four sites and the DOC concentrations within the range of measurements, with the exception of the DOC concentrations in the upper soil horizon at the coniferous forest. However, the Published by Copernicus Publications on behalf of the European Geosciences Union. 938M. Camino-Serrano et al.: ORCHIDEE-SOM model was not able to fully capture the temporal dynamics of DOC concentrations. Further model improvements should focus on a plant-and depth-dependent parameterization of the new input model parameters, such as the turnover times of DOC and the microbial carbon use efficiency. We suggest that this new soil module, when parameterized for global simulations, will improve the representation of the global carbon cycle in LSMs, thus helping to constrain the predictions of the future SOC response to global warming.

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“…[O 2 ] a is atmospheric oxygen concentration (set to 8.45 mol m −3 ), S is dissolvable organic carbon (DOC) concentration (set to 3 mol m −3 ; we note that SUPECA is able to accommodate more specific carbon compounds (like in Riley et al, 2014), yet our recent analysis (Dwivedi et al, 2017) suggests that a lumped DOC is sufficient for simple applications like the one we present here), and M is soil mineral sorbent concentration (with variable values). All concentrations are defined with units (mol m −3 ).…”

Section: Discussionmentioning

confidence: 99%

“…Among these, developing better model structures and mathematical formulations have been identified as priorities. One proposed structural improvement is to include explicit microbial dynamics (Wieder et al, 2015b), which may enable better predictions of global soil carbon stocks (Wieder et al, 2013), priming effects (Sulman et al, 2014), vertical soil carbon profiles Dwivedi et al, 2017), and respiratory temperature sensitivity (Tang and Riley, 2015). A second proposal is to explicitly resolve ecosystem nutrient cycles, following the hypothesis that the potential for increasing land ecosystem carbon uptake from atmospheric CO 2 fertilization could be limited by nutrient availability (Vitousek, 1982;Shi et al, 2016;Wieder et al, 2015c).…”

Section: Introductionmentioning

confidence: 99%

“…A common feature that underlies these two proposed model structural improvements is substrate-consumer interactions, which affect microbial substrate decomposition (Grant et al, 1993;Tang and Riley, 2013a;Riley et al, 2014;Le Roux et al, 2016), mineral soil interactions with adsorptive substrates (Smith, 1979;Grant et al, 1993;Resat et al, 2012;Tang and Riley, 2015;Dwivedi et al, 2017), and plantmicrobe competition for nutrients (Grant, 2013;Zhu et al, 2016aZhu et al, , b, 2017. In soil, because there are many consumers competing for many substrates in different places at different times, soil biogeochemical models must be able to scale consistently across space, time, and processes.…”

Section: Introductionmentioning

confidence: 99%

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SUPECA kinetics for scaling redox reactions in networks of mixed substrates and consumers and an example application to aerobic soil respiration

Tang

Riley

2017

Geosci. Model Dev.

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Abstract. Several land biogeochemical models used for studying carbon-climate feedbacks have begun explicitly representing microbial dynamics. However, to our knowledge, there has been no theoretical work on how to achieve a consistent scaling of the complex biogeochemical reactions from microbial individuals to populations, communities, and interactions with plants and mineral soils. We focus here on developing a mathematical formulation of the substrate-consumer relationships for consumer-mediated redox reactions of the form A+B E → products, where products could be, e.g., microbial biomass or bioproducts. Under the quasi-steady-state approximation, these substrate-consumer relationships can be formulated as the computationally difficult full equilibrium chemistry problem or approximated analytically with the dual Monod (DM) or synthesizing unit (SU) kinetics. We find that DM kinetics is scaling inconsistently for reaction networks because (1) substrate limitations are not considered, (2) contradictory assumptions are made regarding the substrate processing rate when transitioning from single-to multi-substrate redox reactions, and (3) the product generation rate cannot be scaled from one to multiple substrates. In contrast, SU kinetics consistently scales the product generation rate from one to multiple substrates but predicts unrealistic results as consumer abundances reach large values with respect to their substrates. We attribute this deficit to SU's failure to incorporate substrate limitation in its derivation. To address these issues, we propose SUPECA (SU plus the equilibrium chemistry approximation -ECA) kinetics, which consistently imposes substrate and consumer mass balance constraints. We show that SUPECA kinetics satisfies the partition principle, i.e., scaling invariance across a network of an arbitrary number of reactions (e.g., as in Newton's law of motion and Dalton's law of partial pressures). We tested SUPECA kinetics with the equilibrium chemistry solution for some simple problems and found SU-PECA outperformed SU kinetics. As an example application, we show that a steady-state SUPECA-based approach predicted an aerobic soil respiration moisture response function that agreed well with laboratory observations. We conclude that, as an extension to SU and ECA kinetics, SUPECA provides a robust mathematical representation of complex soil substrate-consumer interactions and can be applied to improve Earth system model (ESM) land models.

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Mineral properties, microbes, transport, and plant-input profiles control vertical distribution and age of soil carbon stocks

Cited by 75 publications

References 114 publications

Morphogenesis of a Floodplain as a Criterion for Assessing the Susceptibility to Water Pollution in an Agriculturally Rich Valley of a Lowland River

Morphogenesis of a Floodplain as a Criterion for Assessing the Susceptibility to Water Pollution in an Agriculturally Rich Valley of a Lowland River

ORCHIDEE-SOM: modeling soil organic carbon (SOC) and dissolved organic carbon (DOC) dynamics along vertical soil profiles in Europe

SUPECA kinetics for scaling redox reactions in networks of mixed substrates and consumers and an example application to aerobic soil respiration

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