Vertical pattern of organic matter decomposability in cryoturbated permafrost-affected soils
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Vertical pattern of organic matter decomposability in cryoturbated permafrost-affected soils. / Beer, Christian; Knoblauch, Christian; Hoyt, Alison M.; Hugelius, Gustaf; Palmtag, Juri; Mueller, Carsten W.; Trumbore, Susan.
I: Environmental Research Letters, Bind 17, Nr. 10, 104023, 2022.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Vertical pattern of organic matter decomposability in cryoturbated permafrost-affected soils
AU - Beer, Christian
AU - Knoblauch, Christian
AU - Hoyt, Alison M.
AU - Hugelius, Gustaf
AU - Palmtag, Juri
AU - Mueller, Carsten W.
AU - Trumbore, Susan
PY - 2022
Y1 - 2022
N2 - Permafrost thaw will release additional carbon dioxide into the atmosphere resulting in a positive feedback to climate change. However, the mineralization dynamics of organic matter (OM) stored in permafrost-affected soils remain unclear. We used physical soil fractionation, radiocarbon measurements, incubation experiments, and a dynamic decomposition model to identify distinct vertical pattern in OM decomposability. The observed differences reflect the type of OM input to the subsoil, either by cryoturbation or otherwise, e.g. by advective water-borne transport of dissolved OM. In non-cryoturbated subsoil horizons, most OM is stabilized at mineral surfaces or by occlusion in aggregates. In contrast, pockets of OM-rich cryoturbated soil contain sufficient free particulate OM for microbial decomposition. After thaw, OM turnover is as fast as in the upper active layer. Since cryoturbated soils store ca. 450 Pg carbon, identifying differences in decomposability according to such translocation processes has large implications for the future global carbon cycle and climate, and directs further process model development.
AB - Permafrost thaw will release additional carbon dioxide into the atmosphere resulting in a positive feedback to climate change. However, the mineralization dynamics of organic matter (OM) stored in permafrost-affected soils remain unclear. We used physical soil fractionation, radiocarbon measurements, incubation experiments, and a dynamic decomposition model to identify distinct vertical pattern in OM decomposability. The observed differences reflect the type of OM input to the subsoil, either by cryoturbation or otherwise, e.g. by advective water-borne transport of dissolved OM. In non-cryoturbated subsoil horizons, most OM is stabilized at mineral surfaces or by occlusion in aggregates. In contrast, pockets of OM-rich cryoturbated soil contain sufficient free particulate OM for microbial decomposition. After thaw, OM turnover is as fast as in the upper active layer. Since cryoturbated soils store ca. 450 Pg carbon, identifying differences in decomposability according to such translocation processes has large implications for the future global carbon cycle and climate, and directs further process model development.
KW - Lena-Delta
KW - transport
KW - fractionation
KW - carbon
KW - residence time
KW - radiocarbon
KW - CARBON STOCKS
KW - RADIOCARBON
KW - LANDSCAPE
KW - BUDGETS
KW - SIBERIA
KW - STORAGE
KW - ISLAND
KW - DELTA
KW - SITE
U2 - 10.1088/1748-9326/ac9198
DO - 10.1088/1748-9326/ac9198
M3 - Journal article
VL - 17
JO - Environmental Research Letters
JF - Environmental Research Letters
SN - 1748-9326
IS - 10
M1 - 104023
ER -
ID: 322654754