Carbon Sequestration Related to Soil Physical and Chemical Properties in the High Arctic

Abstract

The diverse aspects of climate change are anticipated to be most pronounced at high latitudes (IPCC, 2013). Among them, increasing temperature, extended growing season, and changes in precipitation regimes affect both above and belowground functioning of Arctic ecosystems (Post et al., 2009). Arctic soils are an important reservoir in the global carbon (C) budget, storing an estimated 1,035 ± 150 Pg C in the top 3 m as soil organic C (SOC; Hugelius et al., 2014). Climate change may drastically alter the reactivity and size of this reservoir via the response of two opposing processes: on the one hand, the thawing of permafrost accelerates C release from the soil, on the other hand, increased vegetation growth results in a greater C input into the soil (Jeong et al., 2018;Zimov et al., 2006).Boundaries between the high and low Arctic were defined by a combination of physical and biological characteristics according to Bliss (1997). While the high Arctic is dominated by arctic deserts with prevailing cushion, rosette and graminoid growth forms, various forms of tundra dominate the low Arctic, where woody and graminoid growth forms are common. Scientific attention has focused primarily on the larger areal component of Arctic soils, that is, the low Arctic. However, the high Arctic environment with low temperatures and precipitation and a short growing season (all of which contribute to quite low net production and sparse ground cover; e.g., Chapin, 1987;Jones & Henry, 2003;Svoboda & Henry, 1987), is potentially even more threatened by climate change (Ravolainen et al., 2020). High Arctic soils may store only 1% of the Abstract Arctic soils are an important reservoir of soil organic carbon (SOC) and their role in determining arctic ecosystem functioning in global carbon budgets requires closer attention. We investigated the coupling of soil properties and SOC stabilization mechanisms in high Arctic terrestrial habitats differing in vegetation cover and organic matter input. We focused on soil physical and chemical properties in glacier foreland, soil crust, dry tundra, wet tundra, and bird cliff meadow habitats on Svalbard (Norway). Concurrently, we performed physical fractionation to determine the amount of SOC stabilized by mineral associations or occlusion in macro and microaggregates. Initial stages of soil development (glacier foreland and soil crust habitats) exhibited characteristically high bulk density and pH, and low moisture and nutrient contents, whereas more developed soils (dry and wet tundra habitats) showed opposite trends. Contrastingly, bird cliff meadow showed low bulk density, intermediate moisture, and very high nutrient content. The amount of SOC stabilized by mineral associations and occlusion in aggregates generally increased with vegetation cover; hence, the more developed habitats supported higher contents of stabilized SOC. However, SOC was stabilized in aggregates even in initial stages of soil development. SOC content in most fractions correlated positively with contents of dissolved organ...

Breaking the Ecosystem Balance Over the Tibetan Plateau

“…In contrast, soil degradation, owing to soil thermal regime and instability, which particularly over sensitive permafrost regions at high altitudes and latitudes store approximately 50% of the world's SOC (C. C. Mu et al., 2020), will emit more CO 2 into the atmosphere and reduce the SOC storage (C. Mu et al., 2016). SOC decreases as soil BD and pH increases, due to the decrease in soil aggregate stability and soil porosity (Jílková et al., 2021). A weakening soil aggregates combined with the changes in the sources of Ca 2+ , Mg 2+ , and Na + , can induce a weakening SOC protection to against biodegradation (L. Chen et al., 2019).…”

Tardigrade distribution in soils of high Arctic habitats

“… 2021 , Jílková et al. 2021 ) and the observed differences in nutrient content among polar habitats can show more pronounced effects on tardigrades than in the previous studies, i.e. in coniferous soils of central Sweden (Hyvönen and Persson 1996 ) and oak, laurel and pine forests of California (Sánchez‐Moreno et al., 2008 ).…”

“…We focused on five contrasting habitats that represented a natural gradient of succession, vegetation cover, moisture, nutrients, and soil texture: (1) glacier foreland, (2) soil crust, (3) fell field under bird cliff, (4) dry tundra, and (5) wet tundra (Figures 2 and 3 , Jílková et al. 2021 ).…”

“…stoniness, BD, soil water content (SWC), water‐holding capacity (WHC), total organic carbon (TOC), total nitrogen (TN), and soil texture were collected and analyzed as described in Jílková et al. ( 2021 ) and they are summarized in Tables 1 and 2 .…”

“…Samples for physico-chemical soil properties, i.e. stoniness, BD, soil water content (SWC), water-holding capacity (WHC), total organic carbon (TOC), total nitrogen (TN), and soil texture were collected and analyzed as described in Jílková et al (2021) and they are summarized in Tables 1 and 2. All samples were obtained during July 2017, covering the first half of the growing season (Karlsen et al 2022).…”