A new data set for estimating organic carbon storage to 3 m depth in soils of the northern circumpolar permafrost region

Abstract

Abstract. High-latitude terrestrial ecosystems are key components in the global carbon cycle. The Northern Circumpolar Soil Carbon Database (NCSCD) was developed to quantify stocks of soil organic carbon (SOC) in the northern circumpolar permafrost region (a total area of 18.7 × 10 6 km 2 ). The NCSCD is a geographical information system (GIS) data set that has been constructed using harmonized regional soil classification maps together with pedon data from the northern permafrost region. Previously, the NCSCD has been used to calculate SOC storage to the reference depths 0-30 cm and 0-100 cm (based on 1778 pedons). It has been shown that soils of the northern circumpolar permafrost region also contain significant quantities of SOC in the 100-300 cm depth range, but there has been no circumpolar compilation of Published by Copernicus Publications. G. Hugelius et al.:A new data set for estimating organic carbon storage pedon data to quantify this deeper SOC pool and there are no spatially distributed estimates of SOC storage below 100 cm depth in this region. Here we describe the synthesis of an updated pedon data set for SOC storage (kg C m −2 ) in deep soils of the northern circumpolar permafrost regions, with separate data sets for the 100-200 cm (524 pedons) and 200-300 cm (356 pedons) depth ranges. These pedons have been grouped into the North American and Eurasian sectors and the mean SOC storage for different soil taxa (subdivided into Gelisols including the sub-orders Histels, Turbels, Orthels, permafrost-free Histosols, and permafrost-free mineral soil orders) has been added to the updated NCSCDv2. The updated version of the data set is freely available online in different file formats and spatial resolutions that enable spatially explicit applications in GIS mapping and terrestrial ecosystem models. While this newly compiled data set adds to our knowledge of SOC in the 100-300 cm depth range, it also reveals that large uncertainties remain. Identified data gaps include spatial coverage of deep (> 100 cm) pedons in many regions as well as the spatial extent of areas with thin soils overlying bedrock and the quantity and distribution of massive ground ice. An open access data-portal for the pedon data set and the GIS-data sets is available online at http://bolin.su.se/data/ncscd/. The NCSCDv2 data set has a digital object identifier

Dissolved organic carbon and nitrogen release from boreal Holocene permafrost and seasonally frozen soils of Alaska

“…This has important implications for projected releases from the near-surface permafrost soils which underlie ∼34% of Alaska, more than half of which are predicted to thaw by 2090 (Pastick et al 2015). Carbon ( figure 1(b), Hugelius et al 2013aHugelius et al , 2013b and nitrogen (Harden et al 2012) contents of permafrost soils are spatially variable and thus DOC and TDN release with permafrost thaw will vary accordingly. Histels are estimated to have the greatest mean SOC storage (Hugelius et al 2014) and Turbels to have the greatest mean N storage (Harden et al 2012) in the upper 2 m of circumpolar soils.…”

Permafrost soils and carbon cycling

“…However, as concerns about global warming increased, this raised fears that the organic carbon stored in permafrost-region soils might become a source of rather than a sink for atmospheric carbon (Oechel et al, 1993). Consequently, a series of studies was conducted in the northern circumpolar regions to explore the depth distribution of stored biogenic carbon in Gelisols (Michaelson et al, 1996Ping et al, 1998Ping et al, , 2008bBockheim and Hinkel, 2007;Bockheim et al, 1999;Tarnocai et al, 2009;Hugelius et al, 2010Hugelius et al, , 2013aStrauss et al, 2012Strauss et al, , 2013. Generally, on gentle to moderate slopes of glaciated uplands, SOM was cryoturbated to depths of mostly 80 to 120 cm.…”

“…At present, the largest spatially distributed soils data set from the northern circumpolar region is the Northern Circumpolar Soil Carbon Database (NCSCD), which was initially developed for the estimate. The NCSCD was recently updated with new data for soil depths of 1-3 m as well as deeper Yedoma and deltaic-alluvium deposits (Hugelius et al, 2013a, b). Hugelius et al (2014) used the updated NCSCD to produce the current best overall estimate of 1307 Pg C stored in permafrost region soils (0-3 m depth together with carbon in the deeper Yedoma and deltaic deposits).…”

PALADYN v1.0, a comprehensive land surface–vegetation–carbon cycle model of intermediate complexity

“…In high northern latitudes, the model carbon content is higher than in the HSWD dataset (Fig. 26) but lower than in the NCSCD soil carbon dataset for the permafrost region (Hugelius et al, 2013a, b;Tarnocai et al, 2009) (Fig. 27).…”

“…However, an attempt has been made to estimate the peatland area and carbon using the equilibrium spinup described above. The estimated peatland area from this idealized approach is compared to NCSCD data (Hugelius et al, 2013a, b;Tarnocai et al, 2009) in Fig. 28.…”