Рубрики:
DISSOLVED ORGANIC-MATTER
SCOTS PINE FORESTS
BOREAL FOREST
ISOTOPE GEOCHEMISTRY
PYROGENIC CARBON
ARCTIC TUNDRA
STATE C-13
FIRE
CHARCOAL
ECOSYSTEMS
Кл.слова (ненормированные):
active layer -- benzene polycarboxylic acid method -- black carbon -- catchment -- forest tundra -- permafrost -- raised bogs -- soil organic carbon -- thermokarst -- topography
DISSOLVED ORGANIC-MATTER
SCOTS PINE FORESTS
BOREAL FOREST
ISOTOPE GEOCHEMISTRY
PYROGENIC CARBON
ARCTIC TUNDRA
STATE C-13
FIRE
CHARCOAL
ECOSYSTEMS
Кл.слова (ненормированные):
active layer -- benzene polycarboxylic acid method -- black carbon -- catchment -- forest tundra -- permafrost -- raised bogs -- soil organic carbon -- thermokarst -- topography
Аннотация: Boreal permafrost soils store large amounts of organic carbon (OC). Parts of this carbon (C) might be black carbon (BC) generated during vegetation fires. Rising temperature and permafrost degradation is expected to have different consequences for OC and BC, because BC is considered to be a refractory subfraction of soil organic matter. To get some insight into stocks, variability, and characteristics of BC in permafrost soils, we estimated the benzene polycarboxylic acid (BPCA) method-specific composition and storage of BC, i.e. BPCA-BC, in a 0.44 km(2)-sized catchment at the forest tundra ecotone in northern Siberia. Furthermore, we assessed the BPCA-BC export with the stream draining the catchment. The catchment is composed of various landscape units with south-southwest (SSW) exposed mineral soils characterized by thick active layer or lacking permafrost, north-northeast (NNE) faced mineral soils with thin active layer, and permafrost-affected raised bogs in plateau positions showing in part thermokarst formation. There were indications of vegetation fires at all landscape units. BC was ubiquitous in the catchment soils and BPCA-BC amounted to 0.6-3.0% of OC. This corresponded to a BC storage of 22-3440 g m(-2). The relative contribution of BPCA-BC to OC, as well as the absolute stocks of BPCA-BC were largest in the intact bogs with a shallow active layer followed by mineral soils of the NNE aspects. In both landscape units, a large proportion of BPCA-BC was stored within the permafrost. In contrast, mineral soils with thick active layer or lacking permafrost and organic soils subjected to thermokarst formation stored less BPCA-BC. Permafrost is, hence, not only a crucial factor in the storage of OC but also of BC. In the stream water BPCA-BC amounted on an average to 3.9% of OC, and a yearly export of 0.10 g BPCA-BC m(-2) was calculated, most of it occurring during the period of snow melt with dominance of surface flow. This suggests that BC mobility in dissolved and colloidal phase is an important pathway of BC export from the catchment. Such a transport mechanism may explain the high BC concentrations found in sediments of the Arctic Ocean.
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Полный текст
Держатели документа:
[Guggenberger, Georg
Rodionov, Andrej
Grabe, Matthias] Univ Halle Wittenberg, Inst Agr & Nutr Sci, D-06108 Halle, Germany
[Rodionov, Andrej] Brandenburg Tech Univ Cottbus, Chair Soil Protect & Recultivat, D-03013 Cottbus, Germany
[Shibistova, Olga
Mikheyeva, Natalia
Zrazhevskaya, Galina] RAS, VN Sukachev Inst Forest, Akademgorodok, Krasnoyarsk 660036, Russia
[Grabe, Matthias] Max Planck Inst Biogeochem, D-07745 Jena, Germany
[Kasansky, Oleg A.] RAS, SB, Field Stn Igarka, Permafrost Inst Yakutsk, Igarka 663200, Russia
[Fuchs, Hans] Univ Gottingen, Inst Forest Management & Yield Sci, D-37077 Gottingen, Germany
[Flessa, Heiner] Univ Gottingen, Inst Soil Sci & Forest Nutr, D-37077 Gottingen, Germany
Доп.точки доступа:
Guggenberger, G...; Rodionov, A...; Shibistova, O...; Grabe, M...; Kasansky, O.A.; Fuchs, H...; Mikheyeva, N...; Zrazhevskaya, G...; Flessa, H...