Abstract

Basalt weathering is a key control over the global carbon cycle, though in situ measurements of carbon cycling are lacking. In an experimental, vegetation-free hillslope containing 330 m3 of ground basalt scoria, we measured real-time inorganic carbon dynamics within the porous media and seepage flow. The hillslope carbon flux (0.6-5.1 mg C m-2 h-1) matched weathering rates of natural basalt landscapes (0.4-8.8 mg C m-2 h-1) despite lacking the expected field-based impediments to weathering. After rainfall, a decrease in CO2 concentration ([CO2]) in pore spaces into solution suggested rapid carbon sequestration but slow reactant supply. Persistent low soil [CO2] implied that diffusion limited CO2 supply, while when sufficiently dry, reaction product concentrations limited further weathering. Strong influence of diffusion could cause spatial heterogeneity of weathering even in natural settings, implying that modeling studies need to include variable soil [CO2] to improve carbon cycling estimates associated with potential carbon sequestration methods.

LanguageEnglish (US)
Pages203-206
Number of pages4
JournalGeology
Volume45
Issue number3
DOIs
StatePublished - 2017

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weathering rate
pore space
weathering
basalt
hillslope
carbon sequestration
carbon
soil
inorganic carbon
carbon flux
carbon cycle
in situ measurement
seepage
porous medium
rainfall
vegetation
modeling
product
method

ASJC Scopus subject areas

  • Geology

Cite this

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title = "CO2 diffusion into pore spaces limits weathering rate of an experimental basalt landscape",
abstract = "Basalt weathering is a key control over the global carbon cycle, though in situ measurements of carbon cycling are lacking. In an experimental, vegetation-free hillslope containing 330 m3 of ground basalt scoria, we measured real-time inorganic carbon dynamics within the porous media and seepage flow. The hillslope carbon flux (0.6-5.1 mg C m-2 h-1) matched weathering rates of natural basalt landscapes (0.4-8.8 mg C m-2 h-1) despite lacking the expected field-based impediments to weathering. After rainfall, a decrease in CO2 concentration ([CO2]) in pore spaces into solution suggested rapid carbon sequestration but slow reactant supply. Persistent low soil [CO2] implied that diffusion limited CO2 supply, while when sufficiently dry, reaction product concentrations limited further weathering. Strong influence of diffusion could cause spatial heterogeneity of weathering even in natural settings, implying that modeling studies need to include variable soil [CO2] to improve carbon cycling estimates associated with potential carbon sequestration methods.",
author = "Haren, {Joost van} and Katerina Dontsova and Barron-Gafford, {Greg A.} and Troch, {Peter A.} and Jon Chorover and Delong, {Stephen B.} and Breshears, {David D.} and Huxman, {Travis E.} and Pelletier, {Jon D.} and Saleska, {Scott R.} and Xubin Zeng and Joaquin Ruiz",
year = "2017",
doi = "10.1130/G38569.1",
volume = "45",
pages = "203--206",
journal = "Geology",
issn = "0091-7613",
publisher = "Geological Society of America",
number = "3",

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T1 - CO2 diffusion into pore spaces limits weathering rate of an experimental basalt landscape

AU - Haren,Joost van

AU - Dontsova,Katerina

AU - Barron-Gafford,Greg A.

AU - Troch,Peter A.

AU - Chorover,Jon

AU - Delong,Stephen B.

AU - Breshears,David D.

AU - Huxman,Travis E.

AU - Pelletier,Jon D.

AU - Saleska,Scott R.

AU - Zeng,Xubin

AU - Ruiz,Joaquin

PY - 2017

Y1 - 2017

N2 - Basalt weathering is a key control over the global carbon cycle, though in situ measurements of carbon cycling are lacking. In an experimental, vegetation-free hillslope containing 330 m3 of ground basalt scoria, we measured real-time inorganic carbon dynamics within the porous media and seepage flow. The hillslope carbon flux (0.6-5.1 mg C m-2 h-1) matched weathering rates of natural basalt landscapes (0.4-8.8 mg C m-2 h-1) despite lacking the expected field-based impediments to weathering. After rainfall, a decrease in CO2 concentration ([CO2]) in pore spaces into solution suggested rapid carbon sequestration but slow reactant supply. Persistent low soil [CO2] implied that diffusion limited CO2 supply, while when sufficiently dry, reaction product concentrations limited further weathering. Strong influence of diffusion could cause spatial heterogeneity of weathering even in natural settings, implying that modeling studies need to include variable soil [CO2] to improve carbon cycling estimates associated with potential carbon sequestration methods.

AB - Basalt weathering is a key control over the global carbon cycle, though in situ measurements of carbon cycling are lacking. In an experimental, vegetation-free hillslope containing 330 m3 of ground basalt scoria, we measured real-time inorganic carbon dynamics within the porous media and seepage flow. The hillslope carbon flux (0.6-5.1 mg C m-2 h-1) matched weathering rates of natural basalt landscapes (0.4-8.8 mg C m-2 h-1) despite lacking the expected field-based impediments to weathering. After rainfall, a decrease in CO2 concentration ([CO2]) in pore spaces into solution suggested rapid carbon sequestration but slow reactant supply. Persistent low soil [CO2] implied that diffusion limited CO2 supply, while when sufficiently dry, reaction product concentrations limited further weathering. Strong influence of diffusion could cause spatial heterogeneity of weathering even in natural settings, implying that modeling studies need to include variable soil [CO2] to improve carbon cycling estimates associated with potential carbon sequestration methods.

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