Genesis of organic matter in the Kara Sea bottom sediments

AbstractRiver discharge is the main source of terrigenous sediments in many coastal areas adjacent to estuaries and deltas of large rivers. Spreading and mixing dynamics of river plumes governs transport of suspended sediments and their deposition at sea bottom at these areas. Generally river plumes have very large synoptic and seasonal variability, which cannot be reconstructed from structure of bottom sediments due to their small accumulation velocity. However, bottom sediments can be indicative of variability of river plumes on inter-annual and decadal time scales. In this study we focus on the large Ob and Yenisei buoyant plumes formed in the central part of the Kara Sea. These plumes interact and mix in the area adjacent to the closely located Ob and Yenisei gulfs. Suspended sediments carried by these river plumes have significantly different geochemical characteristics that can be used to detect Ob or Yenisei origin of bottom sediments. Using new geochemical methods we revealed dependence between spreading patterns of these plumes and spatial distribution and vertical structure of bottom sediments in the study area. This relation is confirmed by a good agreement between local wind and discharge conditions reconstructed for 1948–2001 and vertical structure of bottom sediments.

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Radionuclides Distribution and its Sorption Behavior in the Surface Layer of the Kara Sea Bottom Sediments

Geochemistry International ◽

10.1134/s0016702919110041 ◽

2019 ◽

Vol 57 (11) ◽

pp. 1213-1220

Author(s):

N. V. Kuzmenkova ◽

V. V. Krupskaya ◽

E. V. Duriagina ◽

I. N. Semenkov ◽

S. E. Vinokurov

Keyword(s):

Surface Layer ◽

Bottom Sediments ◽

Kara Sea ◽

Sorption Behavior ◽

Sea Bottom

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Sedimentation rates (data on 210pb and 137cs radionuclides) in different facial-genetic types of the Kara sea bottom sediments

Геохимия ◽

10.31857/s0016-752564111158-1174 ◽

2019 ◽

Vol 64 (11) ◽

pp. 1158-1174

Author(s):

V. Yu. Rusakov ◽

A. P. Borisov ◽

G. Yu. Solovieva

Keyword(s):

Bottom Sediments ◽

Sedimentation Rate ◽

Isotope Composition ◽

Original Data ◽

Kara Sea ◽

Sedimentation Rates ◽

Shallow Marine ◽

Novaya Zemlya ◽

Genetic Types ◽

Sea Bottom

In the article original data on isotope composition of natural excess Pb-210 and artificial Cs-137 radionuclides in upper 2550-cm layer of sea-bottom sediments at the Kara Sea (from Ob and Yenisei estuaries, Eastern-Novaya-Zemlya trough, Voronin trough, as well as Sedov bay (Novaya Zemlya)) are presented. The research results showed close tie between sedimentation rates and facial-genetic types of the sea-bottom sediments. Highest sedimentation rates are typical for the terrigenic-estuarine type. The type is divided on tractional load with sedimentation rate 0.40.7 cm per year and mud bank sediments with sedimentation rate 0.71.0 cm per year. The terrigenic-shallow-marine type is characterized by lowest sedimentation rate 0.10.3 cm per year. The background terrigenic-marine type has a broadest spectrum of the sedimentation rates: on trough slope the rates are minimal (likely to terrigenic-shallow-marine type), within central parts of the trough (as a result of gravity creep) the rates may increase up to 0.9 cm per year. Single facial-genetic type is glacial sediments of Navaya Zemlya bays. Measured recent sedimentation rate within inner depression of the Sedov bay is 0.10.2 cm per year.

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Organic Matter in Bottom Sediments of the Northeastern Part of the Kara Sea as an Indicator of Sedimentation

10.3997/2214-4609.201902746 ◽

2019 ◽

Author(s):

I. Litvinenko ◽

A. Kursheva ◽

V. Petrova ◽

G. Batova ◽

I. Morgunova ◽

...

Keyword(s):

Organic Matter ◽

Bottom Sediments ◽

Kara Sea ◽

Northeastern Part

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Radionuclides distribution and its sorption behavior in the Kara sea bottom sediments surface layer

Геохимия ◽

10.31857/s0016-752564111187-1195 ◽

2019 ◽

Vol 64 (11) ◽

pp. 1187-1195

Author(s):

N. V. Kuzmenkova ◽

V. V. Krupskaya ◽

E. V. Duriagina ◽

I. N. Semenkov ◽

S. E. Vinokurov

Keyword(s):

Bottom Sediments ◽

Sea Water ◽

Sorption Isotherms ◽

Sorption Kinetics ◽

Kara Sea ◽

Sorption Behavior ◽

Freundlich Equation ◽

Sea Bottom ◽

Complexation Mechanism ◽

Sorption Characteristics

The sorption characteristics of the Kara sea bottom sediments were investigated. The sediments were collected during scientific expedition of the R/V Akademik Mstislav Keldysh (Cruise AMK-66). The mineral and fraction composition of sediments was determined. It has been found that 137Cs sorbed predominantly by an ion exchange mechanism because of the clay minerals presence in the sediments. At the same time, 243Am and 90Sr sorbed from seawater by the surface complexation mechanism. The sorption kinetics for 243Am was established: about 20 hours, 137Cs: 2 hours, 90Sr: less than an hour. The sorption isotherms shows Cs and Am in experiments on marine and distilled water are described by the Henry equation. The Sr behavior in deionized water is described by the Langmuir equation, in the case of sea water, by the Freundlich equation.

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HEAVY METAL SPECIATION IN BOTTOM SEDIMENTS OF THE VYSHNEVOLOTSKY RESERVOIR

Moscow University Bulletin. Series 4. Geology ◽

10.33623/0579-9406-2018-3-46-54 ◽

2018 ◽

pp. 46-54

Author(s):

O. A. Lipatnikova

Keyword(s):

Heavy Metal ◽

Organic Matter ◽

Bottom Sediments ◽

Metal Speciation ◽

Organic Matter Content ◽

Water Reservoir ◽

Matter Content ◽

Heavy Metal Speciation ◽

Mobile Forms ◽

Manganese Hydroxides

The study of heavy metal speciation in bottom sediments of the Vyshnevolotsky water reservoir is presented in this paper. Sequential selective procedure was used to determine the heavy metal speciation in bottom sediments and thermodynamic calculation — to determine ones in interstitial water. It has been shown that Mn are mainly presented in exchangeable and carbonate forms; for Fe, Zn, Pb и Co the forms are related to iron and manganese hydroxides is played an important role; and Cu and Ni are mainly associated with organic matter. In interstitial waters the main forms of heavy metal speciation are free ions for Zn, Ni, Co and Cd, carbonate complexes for Pb, fulvate complexes for Cu. Effects of particle size and organic matter content in sediments on distribution of mobile and potentially mobile forms of toxic elements have been revealed.

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