Estimation and Sensitivity of Carbon Storage in Permafrost of North-Eastern Yakutia

Abstract

Organic carbon derived from permafrost can provide a substrate for greenhouse gas production where the buried carbon pool thaws and mobilizes into biogeochemical cycles. Much attention has focused on the permafrost carbon of the Yedoma region of Siberia due to the wide distribution of organic and ice‐rich deposits. Here, we present a new estimation of carbon storage in the upper 25 m of permafrost in north‐eastern Yakutia based on a novel database of total carbon (TC) content, bulk density and ice content of permafrost, and a new map of Quaternary deposits derived from drilling data. The stratigraphic units contain 0.6–2.1% TC, with the highest concentrations in the Holocene cover layer and Late Pleistocene Yedoma superhorizon. The largest carbon pool is found in the Pliocene/Middle Pleistocene Olyor superhorizon. The TC pool of Yedoma is estimated to be 1.5–2 times less than that calculated previously. The TC pool of the study area is 31.2 ± 15.2 Pg C spread across 88 000 km2, with a mean specific carbon content of approximately 14.3 kg C m−3. Carbon storage is estimated excluding the ice‐wedge volume and, due to the limited data for Yedoma and Alas deposits, we present a maximal assessment of the carbon pool for the Yedoma region. Refinement of the size of the Yedoma TC pool is critical for quantifying the scale of permafrost feedback to the carbon cycle. Copyright © 2017 John Wiley & Sons, Ltd.

The Molecular Composition of Humic Substances Isolated From Yedoma Permafrost and Alas Cores in the Eastern Siberian Arctic as Measured by Ultrahigh Resolution Mass Spectrometry

“…The data on the yields of alkali‐extracted OM (Table , Figure ) obtained in this study have shown much higher content of this OM in the alas core as compared to the yedoma core. These data are consistent with published results on the higher total carbon density in alas as compared to yedoma layers in the Kolyma River Basin (Shmelev et al, ; Webb et al, ). The higher rates of recent (Holocene) accumulation of OC within the alas sediment formed in the thermokarst lake might account for this difference (Anthony et al, ).…”

“…This makes yedoma deposits particularly susceptible to rapid thaw during warmer climatic periods. The thaw of yedoma over Holocene history leads to its local subsidence giving rise to formation of thermokarst lakes (Shmelev et al, ). The studies on evolution of the thermokarst lakes (Anthony et al, ) have shown their changing role in CH 4 and CO 2 emission: starting from strong CH 4 emission during thaw of Pleistocene yedoma sediments, followed by strong CO 2 uptake due to high primary productivity leading to formation of organic‐rich Holocene sediments, and finally by establishing neutral (peatland type) gaseous exchange of alas sediments formed as a result of complete drain and refreezing of Holocene sediments.…”

Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions

“…The region is mostly flat terrain and consists of different geological regions [74] ( Figure 5). The western and southern part is dominated by fine-grained and ice-rich late Pleistocene yedoma deposits interspersed with thermokarst basins and river valleys and an abundance of thermokarst lakes and basins (Yedoma-Alas Complex) [75].…”

Variability in above- and belowground carbon stocks in a Siberian larch watershed

“…The average carbon density of deep permafrost from yedoma deposits in the Y4 watershed (13.5 kg C m −3 ) was similar to values reported for yedoma in pan-Arctic summary studies (10 +7/−6 kg C m −3 , Strauss et al, 2013;13.0 ± 0.75 kg C m −3 after correction for ice volume, Walter Anthony et al, 2014) and at taiga sites within 100 km of Chersky (12.3-15.4 kg C m −3 after correction for ice volume, Walter Anthony et al, 2014, and references therein; 14.3 kg C m −3 , Shmelev et al, 2017). Carbon density was almost twice as high in the alas, which is consistent with findings indicating that alas and thermokarst soils store substantially more 4290 E. E. Webb et al: Variability in above-and belowground carbon stocks C (∼ 40-70 %; Walter Anthony et al, 2014;Strauss et al, 2013;Siewert et al, 2015) than undisturbed yedoma, a difference that is likely due to higher rates of recent (Holocene) C accumulation at the alas site (Walter Anthony et al, 2014).…”