Estimated storage of amorphous silica in soils of the circum-Arctic tundra region

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Estimated storage of amorphous silica in soils of the circum-Arctic tundra region. / Alfredsson, H.; Clymans, W.; Hugelius, G.; Kuhry, P.; Conley, D. J.

In: Global Biogeochemical Cycles, Vol. 30, No. 3, 01.03.2016, p. 479-500.

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Alfredsson, H. ; Clymans, W. ; Hugelius, G. ; Kuhry, P. ; Conley, D. J. / Estimated storage of amorphous silica in soils of the circum-Arctic tundra region. In: Global Biogeochemical Cycles. 2016 ; Vol. 30, No. 3. pp. 479-500.

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TY - JOUR

T1 - Estimated storage of amorphous silica in soils of the circum-Arctic tundra region

AU - Alfredsson, H.

AU - Clymans, W.

AU - Hugelius, G.

AU - Kuhry, P.

AU - Conley, D. J.

PY - 2016/3/1

Y1 - 2016/3/1

N2 - We investigated the vertical distribution, storage, landscape partitioning, and spatial variability of soil amorphous silica (ASi) at four different sites underlain by continuous permafrost and representative of mountainous and lowland tundra, in the circum-Arctic region. Based on a larger set of data, we present the first estimate of the ASi soil reservoir (0-1 m depth) in circum-Arctic tundra terrain. At all sites, the vertical distribution of ASi concentrations followed the pattern of either (1) declining concentrations with depth (most common) or (2) increasing/maximum concentrations with depth. Our results suggest that a set of processes, including biological control, solifluction and other slope processes, cryoturbation, and formation of inorganic precipitates influence vertical distributions of ASi in permafrost terrain, with the capacity to retain stored ASi on millennial timescales. At the four study sites, areal ASi storage (0-1 m) is generally higher in graminoid tundra compared to wetlands. Our circum-Arctic upscaling estimates, based on both vegetation and soil classification separately, suggest a storage amounting to 219 ± 28 and 274 ± 33 Tmol Si, respectively, of which at least 30% is stored in permafrost. This estimate would account for about 3% of the global soil ASi storage while occupying an equal portion of the global land area. This result does not support the hypothesis that the circum-Arctic tundra soil ASi reservoir contains relatively higher amounts of ASi than other biomes globally as demonstrated for carbon. Nevertheless, climate warming has the potential to significantly alter ASi storage and terrestrial Si cycling in the Arctic.

AB - We investigated the vertical distribution, storage, landscape partitioning, and spatial variability of soil amorphous silica (ASi) at four different sites underlain by continuous permafrost and representative of mountainous and lowland tundra, in the circum-Arctic region. Based on a larger set of data, we present the first estimate of the ASi soil reservoir (0-1 m depth) in circum-Arctic tundra terrain. At all sites, the vertical distribution of ASi concentrations followed the pattern of either (1) declining concentrations with depth (most common) or (2) increasing/maximum concentrations with depth. Our results suggest that a set of processes, including biological control, solifluction and other slope processes, cryoturbation, and formation of inorganic precipitates influence vertical distributions of ASi in permafrost terrain, with the capacity to retain stored ASi on millennial timescales. At the four study sites, areal ASi storage (0-1 m) is generally higher in graminoid tundra compared to wetlands. Our circum-Arctic upscaling estimates, based on both vegetation and soil classification separately, suggest a storage amounting to 219 ± 28 and 274 ± 33 Tmol Si, respectively, of which at least 30% is stored in permafrost. This estimate would account for about 3% of the global soil ASi storage while occupying an equal portion of the global land area. This result does not support the hypothesis that the circum-Arctic tundra soil ASi reservoir contains relatively higher amounts of ASi than other biomes globally as demonstrated for carbon. Nevertheless, climate warming has the potential to significantly alter ASi storage and terrestrial Si cycling in the Arctic.

KW - amorphous Si storage

KW - circum-Arctic tundra

KW - landscape distribution

KW - permafrost

KW - upscaling

KW - wetland

U2 - 10.1002/2015GB005344

DO - 10.1002/2015GB005344

M3 - Article

VL - 30

SP - 479

EP - 500

JO - Global Biogeochemical Cycles

T2 - Global Biogeochemical Cycles

JF - Global Biogeochemical Cycles

SN - 0886-6236

IS - 3

ER -