scholarly journals Lena Delta hydrology and geochemistry: long-term hydrological data and recent field observations

2015 ◽  
Vol 12 (2) ◽  
pp. 345-363 ◽  
Author(s):  
I. Fedorova ◽  
A. Chetverova ◽  
D. Bolshiyanov ◽  
A. Makarov ◽  
J. Boike ◽  
...  
Keyword(s):  
Field Measurements ◽  
High Water ◽  
The Arctic ◽  
Geochemical Processes ◽  
Lena River ◽  
Sediment Fluxes ◽  
Water And Sediment ◽  
Delta Branches ◽  
Ice Complex

Abstract. The Lena River forms one of the largest deltas in the Arctic. We compare two sets of data to reveal new insights into the hydrological, hydrochemical, and geochemical processes within the delta: (i) long-term hydrometric observations at the Khabarova station at the head of the delta from 1951 to 2005; (ii) field hydrological and geochemical observations carried out within the delta since 2002. Periods with differing relative discharge and intensity of fluvial processes were identified from the long-term record of water and sediment discharge. Ice events during spring melt (high water) reconfigured branch channels and probably influenced sediment transport within the delta. Based on summer field measurements during 2005–2012 of discharge and sediment fluxes along main delta channels, both are increased between the apex and the front of the delta. This increase is to a great extent connected with an additional influx of water from tributaries, as well as an increase of suspended and dissolved material released from the ice complex. Summer concentrations of major ion and biogenic substances along the delta branches are partly explained by water sources within the delta, such as thawing ice complex waters, small Lena River branches and estuarine areas.

scholarly journals Lena Delta hydrology and geochemistry

2013 ◽  
Vol 10 (12) ◽  
pp. 20179-20237 ◽  
Author(s):  
I. Fedorova ◽  
A. Chetverova ◽  
D. Bolshiyanov ◽  
A. Makarov ◽  
J. Boike ◽  
...  
Keyword(s):  
High Water ◽  
Middle Part ◽  
The Arctic ◽  
Biogenic Element ◽  
Sediment Runoff ◽  
Lena River ◽  
Water And Sediment ◽  
Water Volumes ◽  
Ice Complex

Abstract. The Lena River forms one of the largest deltas in the Arctic; studying this delta has raised many questions regarding processes that occur there that remain open today. Comparing long-term hydrometric observational data of Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet) from the Khabarova polar station, located at the head of the delta not far from where the Lena River divides into its main branches, with field observations, which have been carried out since 2002 revealed new insights into the hydrological, hydrochemical, and geochemical processes within the delta. Three periods with various water volumes and intensity of fluvial processes were chosen from the long-term record of water and sediment discharge. The role of ice event (ice blockage and ice floating) during high water in reconfiguring branch channels and influencing the volume of sediment runoff was identified. Results were obtained quantifying the increase of water and sediment discharges in the middle part of the delta main branches. This increase is to a great extent connected with an additional influx of water, as well as an increase of suspended and dissolved material released from the ice complex. A range of major ion and biogenic element contents in the delta branches in summer is introduced, and differences specified between the hydrochemical composition of thawing ice complex waters, of small Lena River branches, and of estuarine areas. The conservative character of some dissolved substances was analyzed along the length of the river branches. The contents of carbon and geochemical substances in suspended and bottom sediments are reported.

scholarly journals Short and long-term thermo-erosion of ice-rich permafrost coasts in the Laptev Sea region

2013 ◽  
Vol 10 (2) ◽  
pp. 2705-2765 ◽  
Author(s):  
F. Günther ◽  
P. P. Overduin ◽  
A. V. Sandakov ◽  
G. Grosse ◽  
M. N. Grigoriev
Keyword(s):  
Coastal Erosion ◽  
The Arctic ◽  
Laptev Sea ◽  
Erosion Rates ◽  
The Past ◽  
Mass Fluxes ◽  
Study Sites ◽  
The Laptev Sea ◽  
Ice Complex

Abstract. Permafrost coasts in the Arctic are susceptible to a variety of changing environmental factors all of which currently point to increasing coastal erosion rates and mass fluxes of sediment and carbon to the shallow arctic shelf seas. Rapid erosion along high yedoma coasts composed of Ice Complex permafrost deposits creates impressive coastal ice cliffs and inspired research for designing and implementing change detection studies for a long time, but continuous quantitative monitoring and a qualitative inventory of coastal thermo-erosion for large coastline segments is still lacking. Our goal is to use observations of thermo-erosion along the mainland coast of the Laptev Sea in eastern Siberia to understand how erosion rates depend on coastal geomorphology and the relative contributions of waterline and atmospheric drivers to coastal thermo-erosion over the past 4 decades and in the past few years. We compared multitemporal sets of orthorectified satellite imagery from 1965 to 2011 for three segments of coastline with a length of 73 to 95 km each and analyzed thermo-denudation (TD) along cliff top and thermo-abrasion (TA) along cliff bottom for two nested time periods: long-term rates (the past 39–43 yr) and short term rates (the past 1–3 yr). The Normalized Difference Thermo-erosion Index (NDTI) was used as a proxy that qualitatively describes the relative proportions of TD and TA. Mean annual erosion rates at all three sites were higher in recent years (−5.3 ± 1.31 m a−1) than over the long term mean (−2.2 ± 0.13 m a−1). The Mamontov Klyk coast exhibit primarily spatial variations of thermo-erosion, while intrasite-specific variations were strongest at the Buor Khaya coast, where slowest long-term rates around −0.5 ± 0.08 m a−1 were observed. The Oyogos Yar coast showed continuously rapid erosion up to −6.5 ± 0.19 m a−1. In general, variable characteristics of coastal thermo-erosion were observed not only between study sites and over time, but also within single coastal transects along the cliff profile. Varying intensities of cliff bottom and top retreat are leading to diverse qualities of coastal erosion that have different impacts on coastal mass fluxes. The different extents of Ice Complex permafrost degradation within our study sites turned out to influence not only the degree of coupling between TD and TA, and the magnitude of effectively eroded volumes, but also the quantity of organic carbon released to the shallow Laptev Sea from coastal erosion, which ranged on a long-term from 88 ± 21.0 to 800 ± 61.1 t per km coastline per year and will correspond to considerably higher amounts, if recently observed more rapid coastal erosion rates prove to be persistent.

Peatlands

Ecology ◽  
2012 ◽  
Author(s):  
Dale H. Vitt
Keyword(s):  
Global Climate Change ◽  
Land Surface ◽  
Net Primary Production ◽  
Global Climate ◽  
High Water ◽  
The Arctic ◽  
Nutrient Inputs ◽  
C And N ◽  
The Tropics

Peatland ecosystems are characterized by a substantial accumulation of organic matter in soil (peat), resulting from long-term excess of net primary production at the surface compared to decomposition throughout the peat column. Globally, peatlands cover 3–4 percent of the earth’s land surface, yet they store 25–30 percent of the world’s soil carbon (about 455 Pg of C) and 9–16 percent of the world’s soil nitrogen (8–15 Pg of N) in peat. These large stores of C and N are especially vulnerable to global climate change. Although peatlands occur from the tropics to the Arctic, it is in the boreal region where peatlands are most abundant. The presence of a well-developed ground layer of mosses along with either abundant shrubs or sedges makes the population and community ecology of these ecosystems interesting and challenging. The high water table, presence of anoxia, and isolation from all nutrient inputs—except the atmosphere in some peatlands (bogs)—present unique opportunities to study the hydrology and biogeochemistry.

Spatial and temporal controls on overwash occurrence on a Great Lakes barrier spit

1992 ◽  
Vol 29 (1) ◽  
pp. 102-117 ◽  
Author(s):  
Robin G. D. Davidson-Arnott ◽  
John D. Fisher
Keyword(s):  
Lake Level ◽  
Field Measurements ◽  
High Water ◽  
Water Phase ◽  
Storm Events ◽  
North Shore ◽  
The North ◽  
High Lake Level ◽  
Washover Fan

Field measurements from 1985 to 1990 and sequential aerial photography since 1945 show that overwash plays an extremely important role in the dynamics of Long Point, a large barrier spit on the north shore of Lake Erie. Overwash occurs primarily in the transgressive proximal and central zones of the spit, which together account for some 65% of the total shoreline length of 41 km. During periods of high lake level, over 50% of the shoreline in these zones may be overwashed. Washover morphology ranges from continuous washover terraces in areas of low foredunes to isolated washovers with narrow throats and distinct fans where breaching has occurred through high dunes. Individual overwash events commonly produce deposits on the fan surface 0.25–0.75 m or more in thickness. Washover-fan sediments are dominated by nearly horizontal planar bedding, with deposits near the fan margins often having foreset bedding, reflecting deposition in standing water of the bay or of interdune ponds.The frequency of overwash occurrence is strongly influenced by long-term lake-level fluctuations, which produce a distinct cycle of overwash activity. During the high-water phase more than 40% of the shoreline may consist of active washover fans or inlet breaches. Even storms with a return frequency of 1–2 per year can lead to significant overwash activity, and the washovers are generally reactivated several times in a 2 or 3 year period around the peak water level. During the low-water phase wider beaches offer protection against even extreme storm events, resulting in washover healing and restoration of a continuous foredune.

scholarly journals Short- and long-term thermo-erosion of ice-rich permafrost coasts in the Laptev Sea region

2013 ◽  
Vol 10 (6) ◽  
pp. 4297-4318 ◽  
Author(s):  
F. Günther ◽  
P. P. Overduin ◽  
A. V. Sandakov ◽  
G. Grosse ◽  
M. N. Grigoriev
Keyword(s):  
Coastal Erosion ◽  
The Arctic ◽  
Laptev Sea ◽  
Erosion Rates ◽  
The Past ◽  
Mass Fluxes ◽  
Study Sites ◽  
The Laptev Sea ◽  
Ice Complex

Abstract. Permafrost coasts in the Arctic are susceptible to a variety of changing environmental factors all of which currently point to increasing coastal erosion rates and mass fluxes of sediment and carbon to the shallow arctic shelf seas. Rapid erosion along high yedoma coasts composed of Ice Complex permafrost deposits creates impressive coastal ice cliffs and inspired research for designing and implementing change detection studies for a long time, but continuous quantitative monitoring and a qualitative inventory of coastal thermo-erosion for large coastline segments is still lacking. Our goal is to use observations of thermo-erosion along the mainland coast of the Laptev Sea, in eastern Siberia, to understand how it depends on coastal geomorphology and the relative contributions of water level and atmospheric drivers. We compared multi-temporal sets of orthorectified satellite imagery from 1965 to 2011 for three segments of coastline ranging in length from 73 to 95 km and analyzed thermo-denudation (TD) along the cliff top and thermo-abrasion (TA) along the cliff bottom for two nested time periods: long-term rates (the past 39–43 yr) and short-term rates (the past 1–4 yr). The Normalized Difference Thermo-erosion Index (NDTI) was used as a proxy to qualitatively describe the relative proportions of TD and TA. Mean annual erosion rates at all three sites were higher in recent years (−5.3 ± 1.3 m a−1) than over the long-term mean (−2.2 ± 0.1 m a−1). The Mamontov Klyk coast exhibits primarily spatial variations of thermo-erosion, while intrasite-specific variations caused by local relief were strongest at the Buor Khaya coast, where the slowest long-term rates of around −0.5 ± 0.1 m a−1 were observed. The Oyogos Yar coast showed continuously rapid erosion up to −6.5 ± 0.2 m a−1. In general, variable characteristics of coastal thermo-erosion were observed not only between study sites and over time, but also within single coastal transects along the cliff profile. Varying intensities of cliff bottom and top erosion are leading to diverse qualities of coastal erosion that have different impacts on coastal mass fluxes. The different extents of Ice Complex permafrost degradation within our study sites turned out to influence not only the degree of coupling between TD and TA, and the magnitude of effectively eroded volumes, but also the quantity of organic carbon released to the shallow Laptev Sea from coastal erosion, which ranged on a long-term from 88 ± 21 to 800 ± 61 t per km coastline per year and will correspond to considerably higher amounts, if recently observed more rapid coastal erosion rates prove to be persistent.

Diatoms and aquatic palynomorphs in the sediments of the Eurasian Arctic seas and their significance for paleooceanological investigations in the Arctic

2019 ◽  
pp. 246-251
Author(s):  
Yelena I. Polyakova ◽  
Yekaterina I. Novichkova ◽  
Tatiana S. Klyuvitkina ◽  
Elizaveta A. Agafonova ◽  
Irina M. Kryukova
Keyword(s):  
Bering Sea ◽  
Surface Sediments ◽  
Sea Water ◽  
The Arctic ◽  
Marginal Filter ◽  
Arctic Seas ◽  
Hydrological Parameters ◽  
The Arctic Ocean ◽  
Long Term Studies

Presented the results of long-term studies of diatoms and aquatic palynomorphs in surface sediments of the Arctic seas and the possibility of their use for the reconstructions of paleocirculation water masses, advection of Atlantic and Bering sea water into the Arctic ocean, changes in the river runoff to the seas, sedimentary processes in the marginal filter of the largest rivers, seasonal sea ice cover and other hydrological parameters.

Trends and Prospects of Development of the Oil and Gas Sector in the Context of Digitalization

2020 ◽  
Vol 26 (1) ◽  
pp. 35-45 ◽  
Author(s):  
A. G. Kazanin
Keyword(s):  
Oil And Gas ◽  
Digital Technologies ◽  
Oil And Gas Industry ◽  
Global Market ◽  
The Arctic ◽  
Business And Society ◽  
Gas Industry ◽  
Exploration And Production ◽  
Oil And Gas Sector

The modern oil and gas industry is heavily dependent on the processes and trends driven by the accelerating digitalization of the economy. Thus, the digitalization of the oil and gas sector has become Russia’s top priority, which involves a technological and structural transformation of all production processes and stages.Aim. The presented study aims to identify the major trends and prospects of development of the Russian oil and gas sector in the context of its digitalization and formation of the digital economy.Tasks. The authors analyze the major trends in the development of the oil and gas industry at a global scale and in Russia with allowance for the prospects of accelerated exploration of the Arctic; determine the best practices of implementation of digital technologies by oil and gas companies as well as the prospects and obstacles for the subsequent transfer of digital technologies to the Russian oil and gas industry.Methods. This study uses general scientific methods, such as analysis, synthesis, and scientific generalization.Results. Arctic hydrocarbons will become increasingly important to Russia in the long term, and their exploration and production will require the implementation of innovative technologies. Priority directions for the development of many oil and gas producers will include active application of digital technologies as a whole (different types of robots that could replace people in performing complex procedures), processing and analysis of big data using artificial intelligence to optimize processes, particularly in the field of exploration and production, processing and transportation. Digitalization of the oil and gas sector is a powerful factor in the improvement of the efficiency of the Russian economy. However, Russian companies are notably lagging behind in this field of innovative development and there are problems and high risks that need to be overcome to realize its potential for business and society.Conclusions. Given the strategic importance of the oil and gas industry for Russia, its sustainable development and national security, it is recommendable to focus on the development and implementation of digital technologies. This is crucial for the digitalization of long-term projection and strategic planning, assessment of the role and place of Russia and its largest energy companies in the global market with allowance for a maximum number of different internal and external factors.

scholarly journals Observations of Tidal Flat Sedimentation within a Native and an Exotic Spartina Species

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1566
Author(s):  
Barbara Proença ◽  
Florian Ganthy ◽  
Richard Michalet ◽  
Aldo Sottolichio
Keyword(s):  
Single Point ◽  
Field Measurements ◽  
Species Variation ◽  
Storm Events ◽  
Level Variation ◽  
Wave Forcing ◽  
Bed Elevation ◽  
Sediment Stabilization ◽  
Consistent Response

Field measurements of bed elevation and related wave events were performed within a tidal marsh, on two cordgrass species, Spartina anglica (exotic) and Spartina maritima (native), in the Bay of Arcachon (SW France). Bed- and water-level time series were used to infer on the sediment behavior patterns from short to long term. A consistent response was found between the bed-level variation and the wave forcing, with erosion occurring during storms and accretion during low energy periods. Such behavior was observed within the two species, but the magnitude of bed-level variation was higher within the native than the exotic Spartina. These differences, in the order of millimeters, were explained by the opposite allocation of biomass of the two species. On the long term, the sedimentation/erosion patterns were dominated by episodic storm events. A general sediment deficit was observed on the site, suggested by an overall bed-level decrease registered within both species. However, further verification of within species variation needs to be considered when drawing conclusions. Despite possible qualitative limitations of the experimental design, due to single point survey, this work provides original and considerable field data to the understanding the different species ability to influence bed sediment stabilization and their potential to build marsh from the mudflat pioneer stage. Such information is valuable for coastal management in the context of global change.

scholarly journals Microplastic contamination of the drilling bivalve Hiatella arctica in Arctic rhodolith beds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sebastian Teichert ◽  
Martin G. J. Löder ◽  
Ines Pyko ◽  
Marlene Mordek ◽  
Christian Schulbert ◽  
...  
Keyword(s):  
Polyethylene Terephthalate ◽  
Water Depth ◽  
The Arctic ◽  
Polymer Composition ◽  
Bivalve Species ◽  
Filter Feeder ◽  
Hiatella Arctica ◽  
Long Term Consequences ◽  
Water Depths

AbstractThere is an increasing number of studies reporting microplastic (MP) contamination in the Arctic environment. We analysed MP abundance in samples from a marine Arctic ecosystem that has not been investigated in this context and that features a high biodiversity: hollow rhodoliths gouged by the bivalve Hiatella arctica. This bivalve is a filter feeder that potentially accumulates MPs and may therefore reflect MP contamination of the rhodolith ecosystem at northern Svalbard. Our analyses revealed that 100% of the examined specimens were contaminated with MP, ranging between one and 184 MP particles per bivalve in samples from two water depths. Polymer composition and abundance differed strongly between both water depths: samples from 40 m water depth showed a generally higher concentration of MPs and were clearly dominated by polystyrene, samples from 27 m water depth were more balanced in composition, mainly consisting of polyethylene, polyethylene terephthalate, and polypropylene. Long-term consequences of MP contamination in the investigated bivalve species and for the rhodolith bed ecosystem are yet unclear. However, the uptake of MPs may potentially impact H. arctica and consequently its functioning as ecosystem engineers in Arctic rhodolith beds.

scholarly journals Development and Verification of the Available Number of Water Intake Days in Ungauged Local Water Source Using the SWAT Model and Flow Recession Curves

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1511
Author(s):  
Jung-Ryel Choi ◽  
Il-Moon Chung ◽  
Se-Jin Jeung ◽  
Kyung-Su Choo ◽  
Cheong-Hyeon Oh ◽  
...  
Keyword(s):  
Water Supply ◽  
Water Intake ◽  
Water Resource Management ◽  
Assessment Tool ◽  
Swat Model ◽  
High Water ◽  
Coefficient Of Determination ◽  
Severe Drought ◽  
Regional Government

Climate change significantly affects water supply availability due to changes in the magnitude and seasonality of runoff and severe drought events. In the case of Korea, despite high water supply ratio, more populations have continued to suffer from restricted regional water supplies. Though Korea enacted the Long-Term Comprehensive Water Resources Plan, a field survey revealed that the regional government organizations limitedly utilized their drought-related data. These limitations present a need for a system that provides a more intuitive drought review, enabling a more prompt response. Thus, this study presents a rating curve for the available number of water intake days per flow, and reviews and calibrates the Soil and Water Assessment Tool (SWAT) model mediators, and found that the coefficient of determination, Nash–Sutcliffe efficiency (NSE), and percent bias (PBIAS) from 2007 to 2011 were at 0.92, 0.84, and 7.2%, respectively, which were “very good” levels. The flow recession curve was proposed after calculating the daily long-term flow and extracted the flow recession trends during days without precipitation. In addition, the SWAT model’s flow data enables the quantitative evaluations of the number of available water intake days without precipitation because of the high hit rate when comparing the available number of water intake days with the limited water supply period near the study watershed. Thus, this study can improve drought response and water resource management plans.

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