Fluvial carbon dioxide emission from the Lena River basin during the spring flood

Greenhouse gas (GHG) emission from inland waters of permafrost-affected regions is one of the key factors of circumpolar aquatic ecosystem response to climate warming and permafrost thaw. Riverine systems of central and eastern Siberia contribute a significant part of the water and carbon (C) export to the Arctic Ocean, yet their C exchange with the atmosphere remains poorly known due to lack of in situ GHG concentration and emission estimates. Here we present the results of continuous in situ pCO2 measurements over a 2600 km transect of the Lena River main stem and lower reaches of 20 major tributaries (together representing a watershed area of 1 661 000 km2, 66 % of the Lena's basin), conducted at the peak of the spring flood. The pCO2 in the Lena (range 400-1400 μatm) and tributaries (range 400-1600 μatm) remained generally stable (within ca. 20 %) over the night-day period and across the river channels. The pCO2 in tributaries increased northward with mean annual temperature decrease and permafrost increase; this change was positively correlated with C stock in soil, the proportion of deciduous needleleaf forest, and the riparian vegetation. Based on gas transfer coefficients obtained from rivers of the Siberian permafrost zone (kCombining double low line4.46 md-1), we calculated CO2 emission for the main stem and tributaries. Typical fluxes ranged from 1 to 2 gCm-2d-1 (>99 % CO2, <1 % CH4), which is comparable with CO2 emission measured in the Kolyma, Yukon, and Mackenzie rivers and permafrost-affected rivers in western Siberia. The areal C emissions from lotic waters of the Lena watershed were quantified by taking into account the total area of permanent and seasonal water of the Lena basin (28 000 km2 ). Assuming 6 months of the year to be an open water period with no emission under ice, the annual C emission from the whole Lena basin is estimated as 8.3±2.5 TgCyr-1, which is comparable to the DOC and dissolved inorganic carbon (DIC) lateral export to the Arctic Ocean

Origin of elemental carbon in snow from western Siberia and northwestern European Russia during winter-spring 2014, 2015 and 2016

Short-lived climate forcers have been proven important both for the climate and human health. In particular, black carbon (BC) is an important climate forcer both as an aerosol and when deposited on snow and ice surface because of its strong light absorption. This paper presents measurements of elemental carbon (EC; a measurement-based definition of BC) in snow collected from western Siberia and northwestern European Russia during 2014, 2015 and 2016. The Russian Arctic is of great interest to the scientific community due to the large uncertainty of emission sources there. We have determined the major contributing sources of BC in snow in western Siberia and northwestern European Russia using a Lagrangian atmospheric transport model. For the first time, we use a recently developed feature that calculates deposition in backward (so-called retroplume) simulations allowing estimation of the specific locations of sources that contribute to the deposited mass

Effect of permafrost thawing on organic carbon and trace element colloidal speciation in the thermokarst lakes of western Siberia

To examine the mechanisms of carbon mobilization and biodegradation during permafrost thawing and to establish a link between organic carbon (OC) and other chemical and microbiological parameters in forming thermokarst (thaw) lakes, we studied the biogeochemistry of OC and trace elements (TEs) in a chronosequence of small lakes that are being formed due to permafrost thawing in the northern part of western Siberia. Twenty lakes and small ponds of various sizes and ages were sampled for dissolved and colloidal organic carbon, metals and culturable heterotrophic bacterial cell number. We observed a sequence of ecosystems from peat thawing and palsa degradation due to permafrost subsidence in small ponds to large, km-size lakes that are subject to drainage to, finally, the khasyrey (drained lake) formation. There is a systematic evolution of both total dissolved and colloidal concentration of OC and TEs in the lake water along with the chronosequence of lake development that may be directly linked to the microbial mineralization of dissolved organic matter and the liberation of the inorganic components (Fe, Al, and TEs) from the organo-mineral colloids. &lt;br&gt;&lt;br&gt; In this chronosequence of lake development, we observed an apparent decrease in the relative proportion of low molecular weight &lt;1 kDa (1 kDa ~ 1 nm) OC concentration along with a decrease in the concentration of total dissolved (&lt;0.45 μm) OC. This decrease was accompanied by an increase in the small size organic ligands (probably autochthonous exometabolites produced by the phytoplankton) and a simultaneous decrease in the proportion of large-size organic (humic) complexes of allochthonous (soil) origin. This evolution may be due to the activity of heterotrophic bacterioplankton that use allochthonous organic matter and dissolved nutrients originating from peat lixiviation. Most insoluble TEs demonstrate a systematic decrease in concentration during filtration (5 μm, 0.45 μm) exhibiting a similar pattern among different samples. At the same time, there is an increase in the relative proportion of large size particles over the &lt;1 kDa fraction for most insoluble elements along the chronosequence of lake evolution. TEs are likely to be bound to colloidal OC and coprecipitate with the mineral (Fe, Al) part of the colloids. Upon progressive consumption of dissolved OC by the heterotrophic bacteria, there is liberation of Fe, Al, and insoluble TEs in the water column that may be subjected to coagulation in the form of particles or large-size mineral colloids

Origin of elemental carbon in snow from western Siberia and northwestern European Russia during winter–spring 2014, 2015 and 2016

Short-lived climate forcers have been proven important both for the climate and human health. In particular, black carbon (BC) is an important climate forcer both as an aerosol and when deposited on snow and ice surface because of its strong light absorption. This paper presents measurements of elemental carbon (EC; a measurement-based definition of BC) in snow collected from western Siberia and northwestern European Russia during 2014, 2015 and 2016. The Russian Arctic is of great interest to the scientific community due to the large uncertainty of emission sources there. We have determined the major contributing sources of BC in snow in western Siberia and northwestern European Russia using a Lagrangian atmospheric transport model. For the first time, we use a recently developed feature that calculates deposition in backward (so-called retroplume) simulations allowing estimation of the specific locations of sources that contribute to the deposited mass. EC concentrations in snow from western Siberia and northwestern European Russia were highly variable depending on the sampling location. Modelled BC and measured EC were moderately correlated (R = 0.53–0.83) and a systematic region-specific model underestimation was found. The model underestimated observations by 42 % (RMSE  =  49 ng g−1) in 2014, 48 % (RMSE  =  37 ng g−1) in 2015 and 27 % (RMSE  =  43 ng g−1) in 2016. For EC sampled in northwestern European Russia the underestimation by the model was smaller (fractional bias, FB  &gt;  −100 %). In this region, the major sources were transportation activities and domestic combustion in Finland. When sampling shifted to western Siberia, the model underestimation was more significant (FB  &lt;  −100 %). There, the sources included emissions from gas flaring as a major contributor to snow BC. The accuracy of the model calculations was also evaluated using two independent datasets of BC measurements in snow covering the entire Arctic. The model underestimated BC concentrations in snow especially for samples collected in springtime

Spin resonance in a Luttinger liquid with spin-orbit interaction

Spin-orbit interaction in quantum wires leads to a spin resonance at low temperatures, even in the absence of an external dc magnetic field. We study the effect of electron-electron interaction on the resonance. This interaction is strong in quantum wires. We show that the electron-electron interaction changes the shape of the resonance curve and produces an additional cusp at the plasmon frequency. However, except for very strong electron-electron interaction these changes are weak since this interaction by itself does not break the spin-rotation symmetry that is violated weakly by the spin-orbit interaction and external magnetic field.Comment: 8 pages (including 3 pages of supplementary material), 2 figure

Investigation of correlation of generated nuclearactive particles in the protonantiproton annihilation at momenta 22.4 and 32 GeV / c

Separation of the individual events corresponding to antiproton-proton annihilation gives the possibility to carry out the analysis of multiparticle correlations for generated particles and to compare them with corresponding data for inelastic pp and non-annihilation p̃p interactions..

Using stable isotopes to assess surface water source dynamics and hydrological connectivity in a high-latitude wetland and permafrost influenced landscape

The research has been supported by the NERC/JPI SIWA project (NE/M019896/1); grant issued in accordance with Resolution of the Government of the Russian Federation No. 220 dated 9 April 2010, under Agreement No. 14.B25.31.0001 with Ministry of Education and Science of the Russian Federation dated 24 June 2013 (BIO-GEO-CLIM); grant RFBR No 17-05-00-348a; grant FCP “Kolmogorov” 14.587.21.0036, grant RNF No 15-17-1009, and grant RFBR No 17-55-16008. Stable water isotope data are available in the Natural Environment Research Council (NERC) Environmental Information Data Centre (EIDC) data repository (title: “Stable water isotopes in Western Siberian inland waters”, permanent identifier: https://doi.org/10.5285/ca17e364-638d-4949-befb-b18b3770aec6). We would like to acknowledge the Arctic-GRO and IAEA for their publicly available databases providing supporting data for our analyses. Stream flow data at Nikolskoe was provided by Sergey Vorobiev. Liliya Kovaleva is acknowledged for the artwork in Figure 9. We would like to thank the two anonymous reviewers and the handling editors for their constructive comments that improved the manuscript.Peer reviewedPublisher PD