Flora of diatoms of the surface layer of bottom sediments of small lakes of the southeastern part of Belarus

2004 ◽  
Vol 6 (2) ◽  
pp. 186-198
Author(s):  
G. K. Khursevich ◽  
A. V. Kudelskiy ◽  
S. A. Fedenya ◽  
J. Marphy
1984 ◽  
Vol 19 (2) ◽  
pp. 97-109 ◽  
Author(s):  
R.J. Cornett ◽  
L. Chant ◽  
D. Link

Abstract The average annual flux of Pb-210 from the atmosphere to lake surfaces and to the bottom sediments was measured in seven small lakes located on the Laurentian Shield. Direct atmospheric fallout of Pb-210 was 136 ± 16 Bq m-2 a-1 Streams from the lakes' catchments input an additional 5 to 473 Bq m-2 a-1. Only 16 to 80 percent of the total input was found in the lake sediments. The fractional rate constant for Pb-210 sedimentation from the water column ranged from 0.25 to 5.3 per annum.


2020 ◽  
Vol 66 (2) ◽  
pp. 180-197
Author(s):  
E. S. Kolpakova ◽  
A. V. Velyamidova

The article presents the results of studies of the environmental properties of organochlorines which differ in properties and origin, in the lake ecosystems of the Bolshezemelskaya tundra (Nenets Autonomous Okrug, Russia). The purpose of this study was to evaluate and assess the levels, distribution characteristics and composition of organochlorines in the bottom sediments of small lakes located in the Adzva river basin in Pymvashor natural boundary (the northernmost location of the exit of thermal-mineral springs of the continental Europe) and in the adjacent area, outside this unique subarctic hydrothermal zone.In order to meet this goal, multi-method (hydrochemical, geochemical, etc.) research was carried out using standard generally approved laboratory practices with their adaptation to the study goals. The quantitative content and composition of the target individual organochlorines were determined by gas chromatographic method with electron-capture detection.The presence of chlorophenol compounds and polychlorinated benzenes (including persistent organic pollutants) was shown in the lakes sediments. The influence of specific microclimatic conditions of subarctic hydrothermal system on the composition and distribution of chlorophenol compounds in lake sediments was considered. In the small lake sediment core in Pymvashor natural boundary a reducing trend in the levels of organochlorines with depth has been recorded (conditioned among other things by the lithological features of bottom sediments). The chlorophenol compounds were found at highest concentrations (619.3–765.5 ng/g) in the sediment upper layers, rich in organic matter; chlorophenol composition was represented mainly by chlorinated phenols, most likely of biotic origin. A lower concentration (185.0 ng/g) of chlorophenol compounds of predominantly abiogenic origin was determined in the lake sediments outside hydrothermal system. The presence and levels of persistent organochlorine pollutants (pentachlorophenol 0.1–2.4 ng/g; hexa- and pentachlorobenzenes 0.4–3.6 ng/g) in the lake sediments were associated with long-range atmospheric transport from various origin sources in nearby regions and low-latitude territories.


2019 ◽  
Vol 57 (11) ◽  
pp. 1213-1220
Author(s):  
N. V. Kuzmenkova ◽  
V. V. Krupskaya ◽  
E. V. Duriagina ◽  
I. N. Semenkov ◽  
S. E. Vinokurov

2021 ◽  
Vol 6 (4) ◽  
pp. 299-307
Author(s):  
Gulnara N. Shigabaeva ◽  
Andrey V. Soromotin ◽  
Еvgeny V. Galunin ◽  
Аnna V. Ruseikina ◽  
Anna А. Kurbash ◽  
...  

The article analyzes and provides data on the processes of accumulation of heavy metals by bottom sediments from the point of view of environmental assessment. The purpose of this paper is to identify the degree of anthropogenic influence on the lakes of the Tazovskiy and Surgut districts, and assess the ecological state of water bodies and adjacent territories. The main processes occurring in natural reservoirs, which lead to the transfer of toxicants into the environment, are considered. The data of quantitative chemical analysis of bottom sediments of two groups of natural reservoirs with an assessment of their ecological state according to the results of statistical processing of the measured values were obtained. Excess concentrations of metals were recorded: for mobile forms – 2200 times for Fe, 1050 times for Mn, 35 times for Cr, 20 times for Co, up to 15 times for Ni, 5 times for Cu, 3 times for Pb, for acid-soluble forms – 45 000 times for Fe, 550 times for Pb, up to 75 times for Ni, 525 times for Mn, 105 times for Cr, 50 times for Cu, 16 times for Co. The geochemical interpretation of the results of the factor analysis is presented.


2019 ◽  
Vol 485 (2) ◽  
pp. 221-225
Author(s):  
V. V. Kolka ◽  
O. P. Korsakova ◽  
N. B. Lavrova ◽  
T. S. Shelekhova ◽  
N. E. Zaretskaya

This paper reports on the lithological, micropaleontological, and chronometric data (radiocarbon dating) for one of the areas of the White Sea coast. The sedimentary sequences were studied in the current lake basins, which were separated from the large basin at different times. The basin was situated in the head of the current Onega Bay. On the basis of these data, the bottom sediments were stratified and the Late Pleistocene-Holocene paleogeographic settings were reconstructed for the southeastern part of Onega Bay.


2021 ◽  
pp. 531-547
Author(s):  
I.A. Nemirovskaya ◽  
◽  
A.M. Titova ◽  
A.V. Khramtsova ◽  
◽  
...  

Hydrocarbons in water, suspended matter and bottom sediments of the Barents Sea were studied based on materials from expeditions to the RV Akademik Mstislav Keldysh in 2016–2019. It is shown that at present there is no oil pollution in open areas of the Barents Sea. With the transition from early summer (2019) to autumn (2016), there was a decrease in hydrocarbon concentrations in surface waters, caused by a change in the biochemical composition of organic matter (possibly due to a decrease in the area of ice). With depth, the HC content decreased mainly. An exception was observed in the area of gutters and deposits, where in the bottom nepheloid layers there was an increase in the concentration of hydrocarbons in suspension and in the surface layer of bottom sediments, and in the thickness of the sediments there was no dependence on their distribution and organic carbon.


2021 ◽  
pp. 278-286
Author(s):  
A.N. Novigatsky ◽  
◽  
A.P. Lisitzin ◽  
V.P. Shevchenko ◽  
A.A. Klyuvitkin ◽  
...  

The monthly, seasonal and annual quantity estimates of vertical fluxes of sedimentary matter from the surface layer of the Arctic Ocean, performed out over the years by various researchers, are the basis for direct calculations of incoming chemical components, minerals, and various pollutants to the surface layer of bottom sediments.


2017 ◽  
Vol 55 (12) ◽  
pp. 1079-1089 ◽  
Author(s):  
V. Yu. Rusakov ◽  
T. G. Kuzmina ◽  
M. A. Levitan ◽  
E. S. Toropchenova ◽  
A. V. Zhilkina

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