![Hier klicken, um den Treffer aus der Auswahl zu entfernen](images/unchecked.gif) |
Titel |
Organic Carbon and Nitrogen Storages of Soils Covering Yedoma Deposits in the Lena River Delta |
VerfasserIn |
Sebastian Zubrzycki, Lars Kutzbach, Anne Morgenstern, Guido Grosse, Eva-Maria Pfeiffer |
Konferenz |
EGU General Assembly 2014
|
Medientyp |
Artikel
|
Sprache |
Englisch
|
Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 16 (2014) |
Datensatznummer |
250087359
|
Publikation (Nr.) |
EGU/EGU2014-1393.pdf |
|
|
|
Zusammenfassung |
The Lena River Delta (LRD) is located in northeast Siberia and extends over a soil covered
area of around 21,500km2. LRD likely stores more than half of the entire soil organic
carbon (SOC) mass stored in deltas affected by permafrost. LRD consists of several
geomorphic units. Recent studies showed that the spatially dominating Holocene units of the
LRD (61% of the area) store around 240Tg of SOC and 12Tg of nitrogen (N) within the
first meter of ground. These units are a river terrace dominated by wet sedge polygons
and the active floodplains. About 50% of these reported storages are located in
the perennially frozen ground below 50cm depth and are excluded from intense
biogeochemical exchange with the atmosphere today. However, these storages are likely to
be mineralised in near future due to the projected temperature increases in this
region.
A substantial part of the LRD (1,712km2) belongs to the so-called Yedoma
Region, which formed during the Late Pleistocene. This oldest unit of the LRD is
characterised by extensive plains incised by thermo-erosional valleys and large thermokarst
depressions. Such depressions are called Alases and cover around 20% of the
area.
Yedoma deposits in the LDR are known to store high amounts of SOC. However, within
the LRD no detailed spatial studies on SOC and N in the soils overlying Yedoma and
thermokarst depressions were carried out so far.
We present here our “investigation in progress” on soils in these landscape units of the
LRD. Our first estimates, based on 69 pedons sampled in 2008, show that the mean SOC
stocks for the upper 30cm of soils on both units were estimated at 13.0kgm2 ±
4.8kgm2 on the Yedoma surfaces and at 13.1kgm2 ± 3.8kgm2 in the Alases. The
stocks of N were estimated at 0.69kgm2 ± 0.25kgm2and at 0.70kgm2 ±
0.18kgm2 on the Yedoma surfaces and in the Alases, respectively.
The estimated SOC and N pools for the depth of 30cm within the investigated part of the
LRD add to 20.9Tg and 1.1Tg, respectively. The Yedoma surfaces (1,313km2)
store 17.1± 6.3TgSOC and 0.9± 0.3TgN, whereas the Alases (287km2)
store 3.8± 1.1TgSOC and 0.2± 0.05TgN within the investigated depth of
30cm.
Further analyses of the soil core material collected in 2013 will provide SOC and N pool
estimates for a depth of 100cm including both, the seasonally active layer and the
perennially frozen ground. With continuing advanced analyses of an available digital
elevation model, slopes will be designated with their extents and inclinations since the planar
extents of slopes derived from satellite imagery do not correspond to the actual slope soil
surface area, which is vital for spatial SOC and N storage calculations as well as trace gas
release estimates. The actual soil surface area of slopes will be calculated prior to result
extrapolations. |
|
|
|
|
|