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- Hugelius, Gustaf, 1980-, et al.
(författare)
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Estimating soil organic carbon storage in periglacial terrain at very high resolution; a case study from the European Russian Arctic
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- 1 Introduction While recent research advances have significantly increased our understanding of SOC storage in the periglacial landscape, there are still many uncertainties. Local scale studies have shown that the landscape distribution of SOC is highly heterogeneous (e.g. Hugelius and Kuhry, 2009). Some landscape components, such as peat deposits or cryoturbated soil horizons, can dominate local SOC storage. However, there are no clear trends in landscape distribution and regional differences emerge (Kuhry et al., in prep.). We have conducted a very high resolution study of SOC storage in four study sites (Seida and Rogovaya 1-3) in discontinuous permafrost terrain, European Russian Arctic. Point pedon data is upscaled to areal coverage using two different upscaling tools, land cover classifications and soil maps. 2 Methods 2.1 Soil sampling and upscaling Soil sampling was performed (i) along landscape transects and (ii) according to a weighted, stratified random sampling program. Sampling was done in 10 cm increments to 1 m depth or to full depth of peat deposits in a total of 94 sites. Point pedon data is upscaled to areal coverage using two different upscaling tools: 1. Thematic land cover classifications based on multiresolution segmentation of high-resolution Quickbird imagery (2.44 m raster resolution, 17 separate land cover classes, software Definiens Professional 5.0) and: 2. High resolution thematic soil maps following World Reference Base for Soil Resources terminology (20 distinct soil types, median polygon size 1960 m2). Mean SOC storage for each land cover or soil type is multiplied by the areal coverage within the study areas to calculate total storage and landscape partitioning of SOC. Figure 1 illustrates the spatial resolution of the two upscaling tools. It also shows 4 pixels of Landsat TM resolution, representing the highest resolution of previous land cover based SOC storage studies in permafrost terrain. 3 results Preliminary calculations show that the estimates in the four different areas are between 38-58 kg C m-2 for land cover upscaling and between 37-49 kg C m-2 for soil map upscaling. Both upscaling methods yield higher estimates than what has previously been reported for this area (Hugelius and Kuhry, 2009). A majority of SOC is stored in Cryic Histosols or Folic/Histic Cryosols. Contiguous permafrost peat plateaus are present in all study areas, covering ~20-30 % of the landscape. The mean depth of peat deposits in the four plateaus is between 150-250 cm, but it is highly variable (recorded range 30-420 cm). There is no evidence of any significant deep burial of SOC through cryoturbation processes. References Hugelius G. and Kuhry P. 2009, Landscape partitioning and environmental gradient analyses of soil organic carbon in a permafrost environment. Global Biogeochemical Cycles, 23, GB3006, doi:10.1029/2008GB003419. Kuhry, P., Dorrepaal, E., Hugelius G., Schuur, E.A.G. and Tarnocai C., Potential remobilization of permafrost carbon under future global warming. Permafrost and Periglacial Processes, Submitted.
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| 2. |
- Hugelius, Gustaf, et al.
(författare)
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Soil Organic Carbon Pools in a Periglacial Landscape; a Case Study from the Central Canadian Arctic
- 2010
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Ingår i: Permafrost and Periglacial Processes. - : Wiley. - 1045-6740 .- 1099-1530. ; 21:1, s. 16-29
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Tidskriftsartikel (refereegranskat)abstract
- We investigated total storage and landscape partitioning of soil organic carbon (SOC) in continuous permafrost terrain, central Canadian Arctic. The study is based on soil chemical analyses of pedons sampled to 1-m depth at 35 individual sites along three transects. Radiocarbon dating of cryoturbated soil pockets, basal peat and fossil wood shows that cryoturbation processes have been occurring since the Middle Holocene and that peat deposits started to accumulate in a forest-tundra environment where spruce was present (∼6000 cal yrs BP). Detailed partitioning of SOC into surface organic horizons, cryoturbated soil pockets and non-cryoturbated mineral soil horizons is calculated (with storage in active layer and permafrost calculated separately) and explored using principal component analysis. The detailed partitioning and mean storage of SOC in the landscape are estimated from transect vegetation inventories and a land cover classification based on a Landsat satellite image. Mean SOC storage in the 0–100-cm depth interval is 33.8 kg C m−2, of which 11.8 kg C m−2 is in permafrost. Fifty-six per cent of the total SOC mass is stored in peatlands (mainly bogs), but cryoturbated soil pockets in Turbic Cryosols also contribute significantly (17%). Elemental C/N ratios indicate that this cryoturbated soil organic matter (SOM) decomposes more slowly than SOM in surface O-horizons.
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