Quantifying pH buffering capacity in acidic, organic-rich Arctic soils: Measurable proxies and implications for soil carbon degradation

Jianqiu Zheng; Erin C. Berns-Herrboldt; Baohua Gu; Stan D. Wullschleger; David E. Graham

doi:10.1016/j.geoderma.2022.116003

Quantifying pH buffering capacity in acidic, organic-rich Arctic soils: Measurable proxies and implications for soil carbon degradation

Jianqiu Zheng, Erin C. Berns-Herrboldt, Baohua Gu, Stan D. Wullschleger, David E. Graham

Biosciences Division

Research output: Contribution to journal › Article › peer-review

11 Scopus citations

Abstract

Dynamic pH change promoted by biogeochemical reactions in Arctic tundra soils can be a major control on the production and release of CO₂ and CH₄, which contribute to rising global temperatures. Large quantities of soil organic matter (SOM) in these soils are susceptible to microbial decomposition, leading to pH changes during permafrost thaw. Soil pH buffering capacity (β) modulates the extent of pH change but has not been thoroughly studied and represented in predictive ecosystem scale biogeochemical models in Arctic tundra soils. In this study, we generated titration curves for 21 acidic tundra soils from three Arctic sites across northern Alaska, United States of America. Geochemical and hydrological soil properties were evaluated, and correlations with β were developed. Strong correlations between β and both gravimetric water content (Θ_g) (R² = 0.847, p < 0.001) and soil water retention (SWR) (R² = 0.849, p = 0.001) indicate that the ability of soil to retain water could be associated with its buffering properties. Correlations between β and soil organic carbon (SOC) and cation exchange capacity (CEC) were also explored, and relationships to SWR are discussed. These correlations were then used with existing soil databases reporting SOC, CEC, and SWR to estimate β across Alaska soils. We further demonstrated the quantitative relationships between β and the simulated rates of biogeochemical reactions and show that lower β leads to higher soil pH and more CH₄ production. Our study provides simple proxies for β in Arctic soils and highlights the importance and implications of representing soil buffering in predictive models, thereby enabling quantitative coupling between pH dynamics associated with biogeochemical reactions. Integrating β into predictive models of Arctic biogeochemical cycling may reduce model uncertainty and further our understanding of permafrost SOM degradation accelerated by warming.

Original language	English
Article number	116003
Journal	Geoderma
Volume	424
DOIs	https://doi.org/10.1016/j.geoderma.2022.116003
State	Published - Oct 15 2022

Funding

We thank Michael Philben and Xiangping Yin for assistance with various chemical analyses. We thank the Council Native Corporation and Sitnasuak Native Corporation for access to the Council and Teller Road research sites and permitted soil sampling. We appreciate the logistical support for field measurements provided by UIC Science in Utqiaġvik. The NGEE Arctic project is supported by the Office of Biological and Environmental Research in the US Department of Energy's Office of Science under contract DE-AC0500OR22725 with ORNL. Zheng is supported by COMPASS-FME, a multi-institutional project supported by the U.S. Department of Energy, Office of Science, Biological and Environmental Research as part of the Environmental System Science Program. The Pacific Northwest National Laboratory is operated for DOE by Battelle Memorial Institute under contract DE-AC05-76RL01830. Data generated in this study can be accessed on the NGEE-Arctic Data Repository https://doi.org/10.5440/1841590. The original research findings and interpretation in this study are detailed in the article/Supporting Information, and further inquiries can be directed to the corresponding author. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( https://energy.gov/downloads/doe-public-access-plan ). We thank Michael Philben and Xiangping Yin for assistance with various chemical analyses. We thank the Council Native Corporation and Sitnasuak Native Corporation for access to the Council and Teller Road research sites and permitted soil sampling. We appreciate the logistical support for field measurements provided by UIC Science in Utqiaġvik. The NGEE Arctic project is supported by the Office of Biological and Environmental Research in the US Department of Energy’s Office of Science under contract DE-AC0500OR22725 with ORNL. Zheng is supported by COMPASS-FME, a multi-institutional project supported by the U.S. Department of Energy , Office of Science, Biological and Environmental Research as part of the Environmental System Science Program. The Pacific Northwest National Laboratory is operated for DOE by Battelle Memorial Institute under contract DE-AC05-76RL01830 .

Funders	Funder number
COMPASS-FME
Office of Biological and Environmental Research in the US Department of Energy
UIC Science in Utqiaġvik
U.S. Department of Energy
Battelle	DE-AC05-76RL01830
Office of Science	DE-AC0500OR22725
Biological and Environmental Research
Oak Ridge National Laboratory

Keywords

Acid-base
Biogeochemistry
Buffering capacity
Organic matter
Water potential
pH

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10.1016/j.geoderma.2022.116003

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title = "Quantifying pH buffering capacity in acidic, organic-rich Arctic soils: Measurable proxies and implications for soil carbon degradation",

abstract = "Dynamic pH change promoted by biogeochemical reactions in Arctic tundra soils can be a major control on the production and release of CO2 and CH4, which contribute to rising global temperatures. Large quantities of soil organic matter (SOM) in these soils are susceptible to microbial decomposition, leading to pH changes during permafrost thaw. Soil pH buffering capacity (β) modulates the extent of pH change but has not been thoroughly studied and represented in predictive ecosystem scale biogeochemical models in Arctic tundra soils. In this study, we generated titration curves for 21 acidic tundra soils from three Arctic sites across northern Alaska, United States of America. Geochemical and hydrological soil properties were evaluated, and correlations with β were developed. Strong correlations between β and both gravimetric water content (Θg) (R2 = 0.847, p < 0.001) and soil water retention (SWR) (R2 = 0.849, p = 0.001) indicate that the ability of soil to retain water could be associated with its buffering properties. Correlations between β and soil organic carbon (SOC) and cation exchange capacity (CEC) were also explored, and relationships to SWR are discussed. These correlations were then used with existing soil databases reporting SOC, CEC, and SWR to estimate β across Alaska soils. We further demonstrated the quantitative relationships between β and the simulated rates of biogeochemical reactions and show that lower β leads to higher soil pH and more CH4 production. Our study provides simple proxies for β in Arctic soils and highlights the importance and implications of representing soil buffering in predictive models, thereby enabling quantitative coupling between pH dynamics associated with biogeochemical reactions. Integrating β into predictive models of Arctic biogeochemical cycling may reduce model uncertainty and further our understanding of permafrost SOM degradation accelerated by warming.",

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T1 - Quantifying pH buffering capacity in acidic, organic-rich Arctic soils

T2 - Measurable proxies and implications for soil carbon degradation

AU - Zheng, Jianqiu

AU - Berns-Herrboldt, Erin C.

AU - Gu, Baohua

AU - Wullschleger, Stan D.

AU - Graham, David E.

PY - 2022/10/15

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N2 - Dynamic pH change promoted by biogeochemical reactions in Arctic tundra soils can be a major control on the production and release of CO2 and CH4, which contribute to rising global temperatures. Large quantities of soil organic matter (SOM) in these soils are susceptible to microbial decomposition, leading to pH changes during permafrost thaw. Soil pH buffering capacity (β) modulates the extent of pH change but has not been thoroughly studied and represented in predictive ecosystem scale biogeochemical models in Arctic tundra soils. In this study, we generated titration curves for 21 acidic tundra soils from three Arctic sites across northern Alaska, United States of America. Geochemical and hydrological soil properties were evaluated, and correlations with β were developed. Strong correlations between β and both gravimetric water content (Θg) (R2 = 0.847, p < 0.001) and soil water retention (SWR) (R2 = 0.849, p = 0.001) indicate that the ability of soil to retain water could be associated with its buffering properties. Correlations between β and soil organic carbon (SOC) and cation exchange capacity (CEC) were also explored, and relationships to SWR are discussed. These correlations were then used with existing soil databases reporting SOC, CEC, and SWR to estimate β across Alaska soils. We further demonstrated the quantitative relationships between β and the simulated rates of biogeochemical reactions and show that lower β leads to higher soil pH and more CH4 production. Our study provides simple proxies for β in Arctic soils and highlights the importance and implications of representing soil buffering in predictive models, thereby enabling quantitative coupling between pH dynamics associated with biogeochemical reactions. Integrating β into predictive models of Arctic biogeochemical cycling may reduce model uncertainty and further our understanding of permafrost SOM degradation accelerated by warming.

AB - Dynamic pH change promoted by biogeochemical reactions in Arctic tundra soils can be a major control on the production and release of CO2 and CH4, which contribute to rising global temperatures. Large quantities of soil organic matter (SOM) in these soils are susceptible to microbial decomposition, leading to pH changes during permafrost thaw. Soil pH buffering capacity (β) modulates the extent of pH change but has not been thoroughly studied and represented in predictive ecosystem scale biogeochemical models in Arctic tundra soils. In this study, we generated titration curves for 21 acidic tundra soils from three Arctic sites across northern Alaska, United States of America. Geochemical and hydrological soil properties were evaluated, and correlations with β were developed. Strong correlations between β and both gravimetric water content (Θg) (R2 = 0.847, p < 0.001) and soil water retention (SWR) (R2 = 0.849, p = 0.001) indicate that the ability of soil to retain water could be associated with its buffering properties. Correlations between β and soil organic carbon (SOC) and cation exchange capacity (CEC) were also explored, and relationships to SWR are discussed. These correlations were then used with existing soil databases reporting SOC, CEC, and SWR to estimate β across Alaska soils. We further demonstrated the quantitative relationships between β and the simulated rates of biogeochemical reactions and show that lower β leads to higher soil pH and more CH4 production. Our study provides simple proxies for β in Arctic soils and highlights the importance and implications of representing soil buffering in predictive models, thereby enabling quantitative coupling between pH dynamics associated with biogeochemical reactions. Integrating β into predictive models of Arctic biogeochemical cycling may reduce model uncertainty and further our understanding of permafrost SOM degradation accelerated by warming.

KW - Acid-base

KW - Biogeochemistry

KW - Buffering capacity

KW - Organic matter

KW - Water potential

KW - pH

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DO - 10.1016/j.geoderma.2022.116003

M3 - Article

AN - SCOPUS:85132792280

SN - 0016-7061

VL - 424

JO - Geoderma

JF - Geoderma

M1 - 116003

ER -

Quantifying pH buffering capacity in acidic, organic-rich Arctic soils: Measurable proxies and implications for soil carbon degradation

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Keywords

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