Newly initiated carbon stock, organic soil accumulation patterns and main driving factors in the High Arctic Svalbard, Norway

Abstract

High latitude organic soils form a significant carbon storage and deposition of these soils is largely driven by climate. Svalbard, Norway, has experienced millennial-scale climate variations and in general organic soil processes have benefitted from warm and humid climate phases while cool late Holocene has been unfavourable. In addition to direct effect of cool climate, the advancing glaciers have restricted the vegetation growth, thus soil accumulation. Since the early 1900’s climate has been warming at unprecedented rate, assumingly promoting organic soil establishment. Here we present results of multiple organic soil profiles collected from Svalbard. The profiles have robust chronologies accompanied by soil property analyses, carbon stock estimations and testate amoeba data as a proxy for soil moisture. Our results reveal relatively recent initiation of organic soils across the Isfjorden area. The initiation processes could be linked to glacier retreat, and improvement of growing conditions and soil stabilization. Carbon stock analyses suggested that our sites are hot spots for organic matter accumulation. Testate amoebae data suggested drying of soil surfaces, but the reason remained unresolved. If continued, such a process may lead to carbon release. Our data suggest that detailed palaeoecological data from the Arctic is needed to depict the on-going processes and to estimate future trajectories.

Accessing the Low-Polar Molecular Composition of Boreal and Arctic Peat-Burning Organic Aerosol via Thermal Analysis and Ultrahigh-Resolution Mass Spectrometry: Structural Motifs and Their Formation

“…Generally, oxidative conditions reveal higher mass losses than smoldering conditions, which can be explained by more efficient combustion of the peat, whereas during oxygen-depleted smoldering, thermally induced condensation and aromatization reactions lead to the formation of coke residue. , NOR has, in general, higher TGA residues because of its higher mineral content. The sampling location of NOR is in the high Arctic areas covered by ice or tundra with short vegetation . Short and inefficient growing seasons lead to comparatively low peat formation, which is why deposition of mineral soil has a higher impact on the peat composition of NOR than for the other samples.…”

“…The sampling location of NOR is in the high Arctic areas covered by ice or tundra with short vegetation. 60 Short and inefficient growing seasons lead to comparatively low peat formation, which is why deposition of mineral soil has a higher impact on the peat composition of NOR than for the other samples. Regardless of the applied measurement atmosphere, all peat samples reveal a similar mass loss step between 30 and 100 °C that can be attributed to the evaporation of residual water.…”

The ongoing lateral expansion of peatlands in Finland

“…According to our data the lateral expansion development closely followed these climate patterns suggesting that the expansion dynamics in a bigger picture was controlled by climate. However, recent studies have shown a current drying trend in the peatlands of the North (Juselius et al., 2022; Zhang et al., 2020) that could have an adverse effect on the peatland expansion. It can also be hypothesized that during dry and warm climate periods, the peatland margins may have actually retreated instead of expanding due to peat oxidation.…”

The complex composition of organic aerosols emitted during burning varies between Arctic and boreal peat

“…The vegetation at the Svalbard study site (NOR) is characterized as herbaceous moss tundra. Notably, this peatland (NOR) is near a bird cliff which has a strong fertilizing effect, leading to an increased nitrogen content in the peat 57 . Naturally occurring wildfires have been reported for boreal peatlands in Finland and permafrost peatlands 89,90 , but not for Svalbard.…”

“…4a), NOR(−) shows a broad distribution of nitrogen-and sulfur-containing compounds between H/C = 0.6-2 and O/C = 0-0.5, while FIB(−) shows an ellipse-shaped distribution with moderate to high O/C ratios in the chemical space of phenol-like compounds, which were also observed as main products of Sphagnum moss decay in soil organic matter (SOM) analysis of a permafrost bog 56 . The high abundance of nitrogen-containing species in NOR is likely a result of the unique location of the peatland, close to a bird cliff ("Combustion conditions"), which increases the nitrogen content in the peat and consequently in the emitted PM (Supplementary Table 1) 57 . Both intersections also contain a small number of organophosphorus compounds (CHOP and CHN 1 OP), which have previously also been characterized by ESI(−) 21 T FT-ICR MS analysis of wildfire smoke, but with higher H/C ratios 41 .…”