scholarly journals Bioindication of the water salinity dynamics by the microalgae communities in the Lena River Delta, Laptev Sea, Russian Arctic

2021 ◽  
Vol 6 (3) ◽  
pp. 15-28
Author(s):  
S. S. Barinova ◽  
V. A. Gabyshev ◽  
A. P. Ivanova ◽  
O. I. Gabysheva
Keyword(s):  
Species Composition ◽  
River Delta ◽  
Water Bodies ◽  
Water Salinity ◽  
The Arctic ◽  
Laptev Sea ◽  
Russian Arctic ◽  
Lena River ◽  
Lena River Delta ◽  
The Laptev Sea

The Lena River in the Laptev Sea forms a vast delta, one of the largest in the world. The Ust-Lensky State Nature Reserve saves biodiversity on the Lena Delta territory beyond the Arctic Circle, in the zone of continuous permafrost. In recent years, large-scale plans for the development of extractive industries are implemented in this Russian Arctic sector. In this regard, the study of biodiversity and bioindication properties of aquatic organisms in the Lena River estuary area is becoming more and more relevant. This study aims to identify the species composition of microalgae in lotic and lentic water bodies of the Lena River Delta and use their indicator property for water salinity. It was a trace indicator of species distribution over the delta and their dynamics along the delta main watercourses to assess the impact of river waters on the Laptev Sea coastal areas. For this, all previously published materials on algae and chemical composition of the region waters as well as data obtained in recent years for the waters of the lower Lena reach were involved. In total, 700 species considered to 10 phyla were analyzed: Cyanobacteria (83), Euglenozoa (13), Ochrophyta (Chrysophyta, Xanthophyta) (41), Eustigmatophyta (4), Bacillariophyta (297), Miozoa (20), Cryptophyta (3), Rhodophyta (1), Chlorophyta (125), and Charophyta (111). The available materials of the field and reference observations were analyzed using several statistical methods. The study results indicate that hydrological conditions are the main factor regulating the spatial structure of the species composition of the microalgae communities in the Lena River Delta. The distribution of groups of salinity indicators across flowing water bodies reflects the effect of water salinity, and this allows suggesting possible sources of this effect. The mechanism of tracking the distribution of environmental indicators itself is a sensitive method, that reveals even their subtle changes in them; therefore, as an integral method, it can be helpful for further monitoring.

scholarly journals Lena River Delta formation during the Holocene

2014 ◽  
Vol 11 (3) ◽  
pp. 4085-4122 ◽  
Author(s):  
D. Bolshiyanov ◽  
A. Makarov ◽  
L. Savelieva
Keyword(s):  
Sea Water ◽  
River Delta ◽  
The Arctic ◽  
Laptev Sea ◽  
Lena River ◽  
Sea Levels ◽  
Marine Terraces ◽  
Delta Formation ◽  
Carbon Reservoir ◽  
Lena River Delta

Abstract. The Lena River Delta, the largest delta of the Arctic Ocean, differs from other deltas because it consists mainly of organomineral sediments, commonly called peat, that contain a huge organic carbon reservoir. The analysis of Delta sediment radiocarbon ages showed that they could not have formed as peat during floodplain bogging, but accumulated when Laptev Sea water level was high and green mosses and sedges grew and were deposited on the surface of flooded marshes. The Lena River Delta formed as organomineral masses and layered sediments accumulated during transgressive phases when sea level rose. In regressive phases, the islands composed of these sediments and other, more ancient islands were eroded. Each new sea transgression led to further accumulation of layered sediments. As a result of alternating transgressive and regressive phases the first alluvial-marine terrace formed, consisting of geological bodies of different ages. Determining the formation age of different areas of the first terrace and other marine terraces on the coast allowed the periods of increasing (8–6 Ka, 4.5–4 Ka, 2.5–1.5 Ka, 0.4–0.2 Ka) and decreasing (5 Ka, 3 Ka, 0.5 Ka) Laptev Sea levels to be distinguished in the Lena Delta area.

Mercury and methylmercury along a transect from the Lena river estuary across the Laptev Sea Shelf

2020 ◽  
Author(s):  
Van Liem Nguyen ◽  
Birgit Wild ◽  
Örjan Gustafsson ◽  
Igor Semiletov ◽  
Oleg Dudarev ◽  
...  
Keyword(s):  
Organic Matter ◽  
Continental Shelf ◽  
Arctic Ocean ◽  
River Delta ◽  
The Arctic ◽  
Laptev Sea ◽  
Terrestrial Organic Matter ◽  
Lena River ◽  
The Arctic Ocean ◽  
The Laptev Sea

<p>Widespread accelerated permafrost thawing is predicted for this century and beyond. This threatens to remobilize the large amounts of Mercury (Hg) currently ‘locked’ in Arctic permafrost soils to the Arctic Ocean and thus potentially lead to severe consequences for human and wildlife health. Future risks of Arctic Hg in a warmer climate are, however, poorly understood. One crucial knowledge gap to fill is the fate of Hg once it enters the marine environment on the continental shelves. Arctic rivers are already today suggested to be the main source of Hg into the Arctic Ocean, with dissolved and particulate organic matter (DOM and POM, respectively) identified as important vectors for the land to sea transport.</p><p>In this study, we have investigated total Hg (HgT) and monomethylmercury (MeHg) concentrations in surface sediments from the East Siberian Arctic Shelf (ESAS) along a transect from the Lena river delta to the Laptev Sea continental slope. The ESAS is the world’s largest continental shelf and receives large amounts of organic carbon by the great Arctic Russian rivers (e.g., Lena, Indigirka and Kolyma), remobilized from continuous and discontinuous permafrost regions in the river catchments, and from coastal erosion. Data on HgT and MeHg levels in ESAS sediments is however limited. Here, we observed concentrations of Hg ranging from 30 to 96 ng Hg g<sup>-1</sup> d.w. of HgT, and 0.03 to 9.5 ng Hg g<sup>-1</sup> d.w. of MeHg. Similar concentrations of HgT were observed close to the river delta (54 ± 19 ng Hg g<sup>-1</sup> d.w.), where >95 % of the organic matter is of terrestrial origin, and the other section of the transect (42 ± 7 ng Hg g<sup>-1</sup> d.w.) where the terrestrial organic matter is diluted with carbon from marine sources. In contrast, we observed higher concentrations of MeHg close to the river delta (0.72 ± 0.71 ng Hg g<sup>-1</sup> d.w. as MeHg) than further out on the continental shelf (0.031 ± 0.71 ng Hg g<sup>-1</sup> d.w. as MeHg). We also observed a positive correlation between the MeHg:Hg ratio and previously characterized molecular markers of terrestrial organic matter (Bröder et al. Biogeosciences (2016) & Nature Com. (2018)). We thus suggest riverine inputs, rather than in situ MeHg formation, to explain observed MeHg trends.</p>

scholarly journals A multiproxy-based reconstruction of the mid- to late Holocene paleoenvironment in the Laptev Sea off the Lena River Delta (Siberian Arctic)

2020 ◽  
Vol 540 ◽  
pp. 109502
Author(s):  
Оlga Rudenko ◽  
Еkaterina Taldenkova ◽  
Yaroslav Ovsepyan ◽  
Аnna Stepanova ◽  
Henning A. Bauch
Keyword(s):  
Late Holocene ◽  
River Delta ◽  
Laptev Sea ◽  
Lena River ◽  
Siberian Arctic ◽  
Lena River Delta ◽  
The Laptev Sea

scholarly journals Lena River delta formation during the Holocene

2015 ◽  
Vol 12 (2) ◽  
pp. 579-593 ◽  
Author(s):  
D. Bolshiyanov ◽  
A. Makarov ◽  
L. Savelieva
Keyword(s):  
Sea Water ◽  
River Delta ◽  
The Arctic ◽  
Laptev Sea ◽  
Lena River ◽  
Sea Levels ◽  
Marine Terraces ◽  
Delta Formation ◽  
Carbon Reservoir ◽  
Lena River Delta

Abstract. The Lena River delta, the largest delta of the Arctic Ocean, differs from other deltas because it consists mainly of organomineral sediments, commonly called peat, that contain a huge organic carbon reservoir. The analysis of delta sediment radiocarbon ages showed that they could not have formed as peat during floodplain bogging; rather, they accumulated when Laptev Sea water level was high and green mosses and sedges grew and were deposited on the surface of flooded marshes. The Lena River delta formed as organomineral masses and layered sediments accumulated during transgressive phases when sea level rose. In regressive phases, the islands composed of these sediments and other, more ancient islands were eroded. Each new sea transgression led to further accumulation of layered sediments. As a result of alternating transgressive and regressive phases, the first alluvial-marine terrace formed, consisting of geological bodies of different ages. Determining the formation age of different areas of the first terrace and other marine terraces on the coast allowed the periods of increasing (8000–6000 BP (years before present), 4500–4000, 2500–1500, and 400–200 BP) and decreasing (5000, 3000, and 500 BP) Laptev Sea levels to be distinguished in the Lena Delta area.

scholarly journals Arctic climate variability and ice regime of the Lena River delta lakes

2020 ◽  
Vol 163 ◽  
pp. 04008
Author(s):  
Roman Zdorovennov ◽  
Sergey Golosov ◽  
Ilya Zverev ◽  
Galina Zdorovennova ◽  
Irina Fedorova
Keyword(s):  
Climate Variability ◽  
Air Temperature ◽  
Baseline Level ◽  
River Delta ◽  
Arctic Climate ◽  
The Arctic ◽  
Russian Arctic ◽  
Lena River ◽  
Ice Regime ◽  
Lena River Delta

Climate variability in the Russian Arctic in 1991-2017 is examined based on the mesurements of the air temperature at 19 meteorological stations. The average annual air temperature at the stations fluctuated relative to the climatic baseline of 1961-1990 by 0.5-4°C in 1991-2004. Since 2005, it was higher than the climatic baseline at all stations annually. The increase in the air temperature was most pronounced in the winter months from November to February at all stations (more than 15ºC at some stations in some years). The increase in the air temperature in the summer months was noticeably smaller. The baseline level of the average monthly air temperature from November to February was exceeded most prominently at high latitude meteorological stations located at Wiese Island, Severnaya Zemlya, and Franz Josef Land (16-17ºC in some years, starting with 2005). Stations located at a distance from the ocean, such as Khatanga and Tiksi, are characterized by a smaller temperature increase compared to coastal and island stations, such as Barenzburg, Wrangel Island and others. Smaller deviations of the air temperature from the baseline level are typical in the western sector of the Russian Arctic (Murmansk, Svyatoy Nose). The influence of the Arctic climate variability on the ice regime of arctic lakes is considered according to Flake model (http://www.flake.igb-berlin.de/) for the Lena River Delta lakes.

Hydrochemistry and isotopic signatures of subpermafrost groundwater discharge along the eastern slope of the Lena River Delta in the Laptev Sea

2020 ◽  
Vol 590 ◽  
pp. 125515
Author(s):  
Alexander N. Charkin ◽  
Irina I. Pipko ◽  
Galina Yu. Pavlova ◽  
Oleg V. Dudarev ◽  
Andrei E. Leusov ◽  
...  
Keyword(s):  
Groundwater Discharge ◽  
River Delta ◽  
Laptev Sea ◽  
Eastern Slope ◽  
Lena River ◽  
Isotopic Signatures ◽  
Lena River Delta ◽  
The Laptev Sea
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