| 1. |
- Kirpotin, Sergey N., et al.
(författare)
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Russian–EU collaboration via the mega-transect approach for large-scale projects : cases of RF Federal target Programme and SIWA JPI Climate EU Programme
- 2018
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Ingår i: International Journal of Environmental Studies. - : Routledge. - 0020-7233 .- 1029-0400. ; 75:3, s. 385-394
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Tidskriftsartikel (refereegranskat)abstract
- The mega-transect approach is a unique infrastructure which was developed in Tomsk State University for environmental monitoring and landscape-ecological research. The approach can be followed in all seasons, for field sampling, ground-based research on the field stations in combination with remote sensing and ecosystem manipulations. The mega-transect was established as a framework for the concept of Western Siberia as a natural mega-facility, a kind of natural equivalent to CERN’s Large Hadron Collider, to attract leading international research groups. The paper describes cases of Russian Federation Federal target Programme and Siberian Inland Waters Joint Programming Initiative Climate EU Programme as examples of the large-scale international projects which are now resulting.
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| 2. |
- Vorobyev, Sergey N., et al.
(författare)
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Floodplain carbon dioxide emissions strongly exceed those of the main river stem : a case study of the Ob river, western Siberia
- 2024
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Ingår i: Journal of Hydrology. - : Elsevier. - 0022-1694 .- 1879-2707. ; 638
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Tidskriftsartikel (refereegranskat)abstract
- The importance of floodplains in carbon (C) evasion from the lotic systems is especially important in continental plains of low runoff such as the organic-rich Western Siberian Lowland (WSL). To quantify the relative importance of the floodplain compared to main stem CO2 emissions, we monitored a large region of the Ob River's middle course (permafrost-free zone) over 3 months from spring to summer. We calculated seasonal water coverage using remote sensing, GIS and hydrologically-based approaches and measured CO2 emissions using floating chambers. There was a strongly pronounced seasonality in the water area's extent of the floodplain with water covering > 40 % of land during the ∼ 30 days of the most intensive spring flood (May – June) and subsequently declining to ≤ 10 % during summer (July-August). Maximal CO2 emissions were recorded in most shallow water bodies of the floodplain, notably in temporary flooded fens and birch forests. The CO2 emissions during the study period ranged from 0.2 ± 0.2 to 0.9 ± 0.2 g Cm−2 d−1 for the floodplain and 0.03 ± 0.34 g C m−2 d−1 for the Ob's main channel.CO2 emissions from the floodplain were ∼ 163 ± 20 t C per km for the river's main stem during the 95 day study period. The partial contributions of temporary flooded zones, main stem, and permanent lakes / secondary channels to total emissions (1820 km² area) were 70, 16, and 14 %, respectively. Over spring and summer seasons, contributions from flooded zones ranged from 43 to 99 % of total CO2 emissions from water surfaces of the Ob River's middle course. Extrapolation of obtained results to the entire territory of the Ob River floodplain indicates that not accounting for the floodplain emissions may sizably—up to an order of magnitude—underestimate the CO2 emissions from riverine systems in Western Siberia during open water period. Future work on the Ob River floodplain in the permafrost-bearing zone should be prioritized and would allow adequate upscaling of C emission from this environmentally important territory.
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| 3. |
- Vorobyev, Sergey N., et al.
(författare)
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Biogeochemistry of dissolved carbon, major, and trace elements during spring flood periods on the Ob River
- 2019
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Ingår i: Hydrological Processes. - : John Wiley & Sons. - 0885-6087 .- 1099-1085. ; 33:11, s. 1579-1594
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Tidskriftsartikel (refereegranskat)abstract
- Detailed knowledge of the flood period of Arctic rivers remains one of the few factors impeding rigorous prediction of the effect of climate change on carbon and related element fluxes from the land to the Arctic Ocean. In order to test the temporal and spatial variability of element concentration in the Ob River (western Siberia) water during flood period and to quantify the contribution of spring flood period to the annual element export, we sampled the main channel year round in 2014-2017 for dissolved C, major, and trace element concentrations. We revealed high stability (approximately <= 10% relative variation) of dissolved C, major, and trace element concentrations in the Ob River during spring flood period over a 1-km section of the river channel and over 3 days continuous monitoring (3-hr frequency). We identified two groups of elements with contrasting relationship to discharge: (a) DIC and soluble elements (Cl, SO4, Li, B, Na, Mg, Ca, P, V, Cr, Mn, As, Rb, Sr, Mo, Ba, W, and U) negatively correlated (p < 0.05) with discharge and exhibited minimal concentrations during spring flood and autumn high flow and (b) DOC and particle-reactive elements (Al, Fe, Ti, Y, Zr, Nb, Cs, REEs, Hf, Tl, Pb, and Th), some nutrients (K), and metalloids (Ge, Sb, and Te), positively correlated (p < 0.05) with discharge and showed the highest concentrations during spring flood. We attribute the decreased concentration of soluble elements with discharge to dilution by groundwater feeding and increased concentration of DOC and particle-reactive metals with discharge to leaching from surface soil, plant litter, and suspended particles. Overall, the present study provides first-order assessment of fluxes of major and trace elements in the middle course of the Ob River, reveals their high temporal and spatial stability, and characterizes the mechanism of river water chemical composition acquisition.
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| 4. |
- Vorobyev, Sergey N., et al.
(författare)
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Permafrost Boundary Shift in Western Siberia May Not Modify Dissolved Nutrient Concentrations in Rivers
- 2017
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- Identifying the landscape and climate factors that control nutrient export by rivers in high latitude regions is one of the main challenges for understanding the Arctic Ocean response to ongoing climate change. This is especially true for Western Siberian rivers, which are responsible for a significant part of freshwater and solutes delivery to the Arctic Ocean and are draining vast permafrost-affected areas most vulnerable to thaw. Forty-nine small- and medium-sized rivers (10-100,000 km(2)) were sampled along a 1700 km long N-S transect including both permafrost-affected and permafrost-free zones of the Western Siberian Lowland (WSL) in June and August 2015. The N, P, dissolved organic and inorganic carbon (DOC and DIC, respectively), particular organic carbon (POC), Si, Ca, K, Fe, and Mn were analyzed to assess the role of environmental parameters, such as temperature, runoff, latitude, permafrost, bogs, lake, and forest coverage on nutrient concentration. The size of the watershed had no influence on nutrient concentrations in the rivers. Bogs and lakes retained nutrients whereas forests supplied P, Si, K, Ca, DIC, and Mn to rivers. The river water temperature was negatively correlated with Si and positively correlated with Fe in permafrost-free rivers. In permafrost-bearing rivers, the decrease in T northward was coupled with significant increases in PO4, P-tot, NH4, pH, DIC, Si, Ca, and Mn. North of the permafrost boundary (61 degrees N), there was no difference in nutrient concentrations among permafrost zones (isolated, sporadic, discontinuous, and continuous). The climate warming in Western Siberia may lead to a permafrost boundary shift northward. Using a substituting space for time scenario, this may decrease or maintain the current levels of N, P, Si, K, Ca, DIC, and DOC concentrations in rivers of continuous permafrost zones compared to the present state. As a result, the export flux of nutrients by the small- and medium-sized rivers of the Western Siberian subarctic to the Arctic Ocean coastal zone may remain constant, or even decrease.
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