Sub-Surface Carbon Stocks in Northern Taiga Landscapes Exposed in the Batagay Megaslump, Yana Upland, Yakutia

Abstract

The most massive and fast-eroding thaw slump of the Northern Hemisphere located in the Yana Uplands of Northern Yakutia was investigated to assess in detail the cryogenic inventory and carbon pools of two distinctive Ice Complex stratigraphic units and the uppermost cover deposits. Differentiating into modern and Holocene near-surface layers (active layer and shielding layer), highest total carbon contents were found in the active layer (18.72 kg m−2), while the shielding layer yielded a much lower carbon content of 1.81 kg m−2. The late Pleistocene upper Ice Complex contained 10.34 kg m−2 total carbon, and the mid-Pleistocene lower Ice Complex 17.66 kg m−2. The proportion of organic carbon from total carbon content is well above 70% in all studied units with 94% in the active layer, 73% in the shielding layer, 83% in the upper Ice Complex and 79% in the lower Ice Complex. Inorganic carbon is low in the overall structure of the deposits.

Sulfur Isotope Geochemistry of Ice‐Wedges in Yakutia, East Siberia

“…For example, microbial sulfate reduction enriches soil water sulfate in heavy sulfur isotopes, whereas oxidation of 34 S‐depleted sulfide minerals decreases the δ 34 S value of soil water sulfate. As a result, plant sulfur can be isotopically distinct from atmospheric sulfate, where an active biogeochemical sulfur cycle is sustained [20–24, 99]. In this study, most ice‐wedges, with the exception of the Syrdakh wedge, show no significant δ 34 S offset between dissolved sulfate and POM sulfur on average (Figure 4), but the correlation between these two sulfur isotopic proxies is weak (Figure 7A).…”

“…The paleoenvironmental implications of this sulfur isotope variation are discussed in the next section (see discussion in Section 5.2). Although unrelated to sulfur isotopes, the negligible POM content of the lower Batagay ice complex, compared with that of the upper ice complex, could be attributed to limited vegetation development due to rapid sedimentation [100] and/or temporal changes in vegetation type [101].…”

Microbial and Geochemical Evidence of Permafrost Formation at Mamontova Gora and Syrdakh, Central Yakutia

“…The total carbon (TC) in soils and soil particles of the ice (in wt%) was detected by an elemental analyzer (Vario EL CHNS analyser, Germany) The standard deviation for TC was ±0.1% for repeated measurements. Inorganic carbon content in Quaternary deposits of North-Eastern Russia is typically less than 10-15% of TC (Schirrmeister et al, 2011), while recent studies show larger values up to 22% at Batagay IC (Shepelev at al., 2020). Ice wedge samples were melted at room temperature and filtered through pre-weighed filters.…”

Retrogressive Thaw Slumps on Ice‐Rich Permafrost Under Degradation: Results From a Large‐Scale Laboratory Simulation

“…With a length of more than 1,000 m, a width of 800 and 60 m high headwalls in 2019, this mega-RTS is representative of three typical cryolithological types of permafrost at a single site. It is characterized by its ice-rich Yedoma permafrost close to the surface, underlain by ice-poor sands, while at its base a pure groundice layer is present (Shepelev et al, 2020). In close association with the erosion of RTS, small mud flows settling on gentle slopes are observed from melted ice-wedge network and contribute to the transport of sediments, dissolved elements, and meltwater from the melting of ice wedges (Figure 1a).…”