Artyom Lim

Element composition of peat deposits in flat frost mound bogs of the Pyakupur River (northern taiga of West Siberia)

The content and the profile distribution of the element composition of the 1 meter high peat deposits in flat frost mound bogs are investigated. The botanical composition of peat is described. The results of the botanical composition analysis of peat showed that deposits consist mainly of sphagnum mosses, lichens, shrubs, green mosses, pine wood, as well as pine and birch bark. A good correlation between the degree of peat decomposition and the brightness of dry peat measured by the CIE L*a*b* color model is revealed. As a result of the study of peat samples’ color, it has been found that this parameter can be used as an express method for the rapid assessment of peat degree decomposition. The highest concentration of the organic carbon occurs at the base of the peat deposit (64.4±0.2%). The nitrogen concentration in permafrost peat is higher than in thawed (1.0 ± 0.2% and 0.7 ± 0.1%, respectively, the difference is significant at p = 0.001). The C / N ratio decreases from 72 ± 16 in 0-40 cm in the thawed layer to 50 ± 10 in the frozen part (40-100 cm). Within the bottom low boundary of the seasonally thawed layer, a local increase in the N concentration was detected, as well as an almost 2-fold decrease in the C/N ratio. It is most likely related to the high increase in the rate of microbial activity on the border between the thawed layer and the permafrost peat. It was revealed that most of the elements are concentrated in the upper (thawed) part of the peat deposit. Among them, only Na, Mg, Ca, Zn, Ba, As and Sb have a significant difference. Despite the fact that significant differences according to non-parametric U-criterion Mann-Whitney test were identified only for 7 elements, the distribution of the rest along elements the frozen and thawed peat layer is similar in nature. So for Na, Mg, Al, P, K, Ca, Ti, Fe, Zn, Ba, Li, B, V, Cr, Mn, Co, Ni, Cu, Ga, As, Rb, Sr, Y, Zr, Nb, Mo, Cd, Sb, Cs, the upper quartiles of concentrations in the seasonally thawed layer are 1.2 - 6.9 times higher than in the permafrost peat, and for C, N, Al, Ba, B, V, Co, Cu , Zr, Nb, Mo it is 1,0 - 0,6 times lower, respectively. Generally, according to the element composition, it is safe to say that the differences stem from the botanical composition. In general, according to the elemental composition it can be said that the differences are primarily due to the botanical composition. The active layer comprises mainly sphagnum mosses and lichens, the woody peat already appears in the lower permafrost part of the deposit. A correlation between the brightness of peat and the total content of ash elements (R2 = 0.65, excluding 1 sample) was revealed within the active layer. Taking into account the fact that the brightness correlates with the degree of decomposition, it may be concluded that higher upper quartile of the concentrations of elements in the active layer relates to the slower peat accumulation rate for the last 3 thousand years and, correspondingly, a large accumulation of dust components from the atmosphere by the peat layers.

The role of Eurasian beaver (Castor fiber) in the storage, emission and deposition of carbon in lakes and rivers of the River Ob flood plain, western Siberia

Several studies have reported significant emission of greenhouse gasses (GHG) from beaver dams, suggesting that ponds created by beavers are a net source of CO2 and CH4. However, most evidence come from studies conducted in North America (on Castor canadensis) without a parallel comparison with the Eurasian beavers (Castor fiber) impacts and a critical consideration of the importance of the carbon deposition in dam sediments. The most abundant population of the Eurasian beaver lives in Russia, notably within the River Ob watershed in Western Siberia which is the second largest floodplain on Earth. Consequently, we assessed the holistic impact of Eurasian beavers on the multiple carbon pools in water and on other related biogeochemical parameters of the Obs floodplain streams. We compared dammed and flowing streams in a floodplain of the middle course of the river. We found that beavers in western Siberia increase the stream emission of methane by about 15 times by building their dams. This is similar to what has been documented in North America. A new finding from the present study is that Siberian beavers facilitate 1) nutrient recycling by speeding up the nutrient release from particulate organic matter; and 2) carbon sequestration by increasing the amount of dissolved organic carbon. This carbon becomes in part recalcitrant when buried in sediments and is, therefore, removed from the short-term carbon cycle. These new results should be taken into consideration in river management and provide a further reason for the conservation and management of Eurasian Beavers.

Comparative analysis of the river suspension matter of the West Siberian taiga (northern taiga) and tundra zones

The study of suspended solids in the West Siberian rivers is of great importance from the point of view of biogeochemistry, since in the rivers there are the formation and transformation of abrasion products of banks and bottom, suspended and dissolved organic matter and solid river flow, which are carried out from the land to the Kara Sea and further to the North Arctic Ocean. Studies of river suspension are necessary to understand the processes of modern sedimentation, as well as for the ecological assessment of the water area state. Mechanisms of sedimentation are largely associated with the processes of physical and biological weathering, generation, transformation and transport of suspended matter from the catchment to floodplain landscapes. In this regard, the role of studying the connection of the qualitative composition of river suspended matter with landscape parameters (level of the catchment area swappiness, nature of the soil cover, composition of soil-forming rocks, presence (absence) of permafrost, etc. is high. For example, the river of the north-taiga subzone, the catchment area of which is heavily swamped, and the river of the tundra zone with a slightly swampy watershed are represented. The influence of flood waters on the concentration of some elements in rivers with contrasting watersheds is considered. The contribution of groundwater and the effect of soil solutions on the overall migration flow are estimated.

Lithological sequence of soil formation on the low terraces of the Ob and the Tom rivers in the south of Tomsk Oblast

We have investigated the low terraces of the Ob and Tom rivers in the south of Tomsk Oblast, primarily the Ob–Tom interfluve area. This area is situated near Seversk and Tomsk suburbs, where 70% of the Tomsk Oblast population is concentrated. Rapid development of suburban areas and recreation activity, as well as pollutants, threaten the sustainable functioning of the terrace natural complex, where underground freshwater resources used by the citizens are replenished. This paper presents descriptions of ecological factors affecting low terrace soils in this interfluve area. We have studied the lithographic sequence of soil formation in the contact zone between the Aeolian dune and basin fields with sandy and sandy-loam soil-forming rocks and the flatbeds of the terraces with loam mantles undisturbed by Aeolian processes as soil-forming rocks. Protection of these soils should be established by legal instruments.