Hydrochemical Structural Patterns of the Lena River–Laptev Sea Mixing Zone in the Autumn Period

Kostyleva, A. V.; Polukhin, A. A.; Степанова, Светлана

doi:10.1134/s0001437020060053

Cited by 3 publications

(7 citation statements)

References 12 publications

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“…DSi concentrations largely follow salinity trends, with high values (>30 μM) in the LFP, which subsequently decrease in the SFL. This follows previous findings that with exception to OSW, DSi concentrations are well correlated with riverine influence from the Lena River (Kostyleva et al., 2020; Létolle et al., 1993). Over the continental slope, low DSi concentrations are generally observed, reflective of AW poor in DSi owing to its origins in the North Atlantic.…”

Section: Resultssupporting

confidence: 92%

“…During the expedition of AMK73 in October 2018, this extends out northward and contributes to a Surface Freshwater Layer (SFL) in the upper 20 m of the water column, overriding denser, more saline advected and modified AW. Under the LFP, colder, more saline (<1°C, >25 psu) waters are found, characteristic of older shelf waters constrained locally by hydrography (Kostyleva et al., 2020; Létolle et al., 1993). The LFP and SFL are strongly stratified in the summer months from the surrounding waters by steep salinity gradients, restricting the exchange of nutrients, before mixing in the winter (Janout et al., 2020).…”

Section: Resultsmentioning

confidence: 99%

“…The Laptev Sea receives discharge from one of the largest rivers on earth, the Lena River, which supplies large amounts of organic and inorganic nutrients to the surrounding shelf (Holmes et al., 2012; Stedmon et al., 2011). Because of the influence of the Lena River, the hydrography of the Laptev Sea is characterized by large gradients in physical and chemical properties within the water column (Kostyleva et al., 2020; Spivak et al., 2021). As discharge from the Lena River enters the sea, the Lena Freshwater Plume (LFP) is formed.…”

Section: Methodsmentioning

confidence: 99%

“…These shelf waters gradually become more saline as they extend out toward the continental slope where they meet the inflow of AW via the Norwegian Sea. The discharge of the Lena River varies strongly with seasonality as the lower reaches of the catchment freeze in winter contracting the extent of the plume on the shelf, and subsequently expands in spring‐summer as the Lena discharge increases (Kostyleva et al., 2020; Pavlov et al., 1996). Variations from the Lena discharge also affect the chemical and physical properties of the Lena plume in the Laptev Sea.…”

Section: Methodsmentioning

confidence: 99%

“…Variations from the Lena discharge also affect the chemical and physical properties of the Lena plume in the Laptev Sea. Underneath the plume, near‐bottom stagnant waters are found, constrained by local bathymetry (Kostyleva et al., 2020; Létolle et al., 1993).…”

Section: Methodsmentioning

confidence: 99%

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The Importance of Riverine Nutrient Supply for the Marine Silica Pump of Arctic Shelves: Evidence From the Laptev Sea

Debyser,

Pichevin,

Tuerena

et al. 2024

Global Biogeochemical Cycles

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Arctic shelves receive a large load of nutrients from Arctic rivers, which play a major role in the biogeochemical cycles of the Arctic Ocean. In this study, we present measurements of dissolved silicon isotopes (δ30Si(OH)4) around the Laptev Sea and surface waters of the Eurasian shelves collected in October 2018 to document terrestrial silicon modifications on shelves and their contribution to the Arctic basin. Nitrogen was found to be depleted in surface waters and the limiting nutrient to primary production in the Laptev Sea, allowing excess silicon export to the central Arctic Ocean. Heavy δ30Si(OH)4 in the water column was linked to the strong biological removal of DSi on shelves, enabled by vigorous N recycling. From isotopically constrained processes, we estimate that >50% of the silicon from riverine inputs is removed within the Lena River delta and on the Laptev Sea shelf. Extrapolating this to major Siberian rivers, this leads to an export of 2.5 ± 0.8 kmol/s of riverine silicon through the Transpolar Drift. An updated isotopic budget of the Arctic Ocean reproduces the observed δ30Si(OH)4 signatures out of the Arctic Ocean and underlines the importance of biological processes in modulating silicon export. Given that opal burial fluxes on Artic shelves are controlled by denitrification and N‐limitation, these processes are sensitive to ongoing climate change. As a consequence of higher riverine DSi inputs and shelf denitrification responding to productivity, it is inferred that silicon export from the Arctic Ocean could increase in the future, accompanied by lighter δ30Si(OH)4 signatures.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The Importance of Riverine Nutrient Supply for the Marine Silica Pump of Arctic Shelves: Evidence From the Laptev Sea

Debyser,

Pichevin,

Tuerena

et al. 2024

Global Biogeochemical Cycles

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Distribution of Biogenic Elements at the Water-Bottom Boundary in the Pore and Super Bottom Waters of the Kara Sea and the Laptev Sea

Sinitsyna,

Borisenko,

Polukhin

2024

JOR

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The paper presents data from the 63rd cruise of the R/V “Akademik Mstislav Keldysh” in August–October 2015. The main areas of work included the western part of the Kara Sea, the bays of Novaya Zemlya (Sedova, Oga and Tsivolki), a transect through the Voronin Trench, a transect from the Lena River delta to the continental slope of the Laptev Sea. During the cruise, a chemical analysis of pore and bottom waters was carried out for the content of nitrite, nitrate nitrogen, silicon, phosphates, total alkalinity and pH. The patterns of distribution of silicon and phosphorus concentrations at the water-bottom interface are considered. In the Kara Sea analysis of the data showed that the maximum concentrations of nutrients are located in the upper 10 cm sediment layer, below that concentrations gradually decrease. In all studied bays of Novaya Zemlya, the concentrations of nutrients in the silt waters were lower than on the adjacent shelf. In the Laptev Sea, the content of nitrates in silt waters is higher, and phosphates are lower than in the Kara Sea. Differences in the content of nutrients in the bottom and silt water are associated both with external factors (river runoff) and physical and geological features of the upper sediment layer of the studied areas.

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Biogeochemical structure of the Laptev Sea in 2015-2020 associated with the River Lena plume

et al. 2023

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The discharge of rivers and the subsequent dispersion of their plumes play a pivotal role in the biogeochemical cycling of the Arctic Ocean. Based on the data collected during annual transects conducted in the autumn period (September-October) from 2015-2020, this study explores the effect of River Lena plume dispersion on the seasonal and interannual changes in the hydrophysical and biogeochemical structure of the southeastern Laptev Sea. The temperature-salinity relationship (T-S), Redfield ratio and multiparameter cluster analysis were used to investigate variations in the water mass structure along the transect. The results revealed that the plume’s interannual and seasonal spreading patterns play a crucial role in regulating the local physical, biogeochemical, and biological processes in the southern Laptev Sea. During September-October, the hydrochemical water mass structure along the transects shifted from highly stratified to unstratified as the plume’s mixing intensity increased. Anomalous hydrochemical distributions were observed due to coastal upwelling, which was primarily characterized by high total alkalinity and nitrate levels, and low organic phosphorus, nitrite, and ammonia levels in the seawater. Wind and cold weather conditions drive deep vertical mixing of seawater, causing the resuspension of bottom sediment and the subsequent enrichment of bottom water by nutrients. Multi-parameter cluster analysis is used to describe the details of water mass structures in the highly dynamic southern Laptev Sea, with water mass structures typically undergoing significant changes within two weeks between September and October. The migration and transformation of water masses throughout the seasons are influenced by the volume of river discharge, fall-winter cooling, and atmospheric circulation patterns. Furthermore, the general atmospheric circulation is confirmed to be the primary cause of the interannual variation in the spread of the Lena River plume over the southeast Laptev Sea.

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Hydrochemical Structural Patterns of the Lena River–Laptev Sea Mixing Zone in the Autumn Period

Cited by 3 publications

References 12 publications

The Importance of Riverine Nutrient Supply for the Marine Silica Pump of Arctic Shelves: Evidence From the Laptev Sea

The Importance of Riverine Nutrient Supply for the Marine Silica Pump of Arctic Shelves: Evidence From the Laptev Sea

Distribution of Biogenic Elements at the Water-Bottom Boundary in the Pore and Super Bottom Waters of the Kara Sea and the Laptev Sea

Biogeochemical structure of the Laptev Sea in 2015-2020 associated with the River Lena plume

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