Fluxes Of Sedimentary Matter Research Articles

Fluxes and Composition of Particulate Matter in the Water Column of South Baikal (between March 2015 and March 2016)

Abstract —The paper provides the results of experiments with sediment traps in the deep-water part of the South Basin of Lake Baikal (depth of 1366 m), installed from March 2015 to March 2016 in order to study recent sedimentation within the lake. We present new data on total fluxes of particulate matter and fluxes of biogenic components (SiO2biog, Сorg, and Ntot) at different depths of the water column both for the whole year and for individual periods of the year. Diatom analyses were carried out for all obtained samples. The total flux of sedimentary material averaged 94.9 g/m2/y; the average fluxes of SiO2biog, Сorg, and Ntot were 23.9, 11.6, and 0.94 g/m2/y, respectively. The molar C/N ratio varies from 11 to 21 and indicates a predominance of allochthonous material in almost all samples. Maximum fluxes of sedimentary matter were recorded from 20 June to 20 July 2015. This period corresponds to the bloom of diatoms of the species Synedra acus. This species amounts to >94% of the total diatom content in all samples taken during this year. The recent predominance of Synedra acus in the water column, as well as in the surface bottom sediments of South Baikal, is probably due to the climate warming.

Dispersed Sedimentary Matter in the Marine Cryosystem: Snow–Drifting Ice–Icewater of the Arctic and Antarctic

A comparative description of sedimentary matter in the snow–ice cover of the Circumpolar Arctic and fast ice of the Antarctic is given. The main distribution patterns of dispersed sedimentary matter in the marine cryosystem of snow–sea ice–ice water of the Arctic and Antarctica are obtained. Sedimentary matter fluxes from the bottom of sea ice to the ocean bottom are calculated.

Studies of particle fluxes of sedimentary matter along multiyear transoceanic section in northern Atlantic and Arctic interaction area

New data on the particle fluxes of sedimentary matter and its main components at the meridional section along 59°30' N in the North Atlantic under the influence of multidirectional transfer of water masses are given. The material for the study was collected for two years from July 2015 to July 2017 using sediment traps installed as part of four automatic deep-water sedimentary observatories. In the subsurface layer, the annual variation of the fluxes and the change in the composition of the sinking matter are determined by the primary production. Near-bottom fluxes of sedimentary matter on the slopes of the Reykjanes ridge are formed under conditions of water masses and, respectively, suspended particulate matter transfer in a south-westerly direction along the ridge from the Iceland-Faeroe and Greenland-Iceland rises. There is a reverse directional transfer of matter at the foot of the European continental slope. The composition of the sinking matter is dominated by the biogenic component, the proportion of which decreases with depth due to dissolution, and in winter due to the weakening of the biological activity of the upper active layer. The role of lithogenic matter is maximal in the bottom layer, including due to the supply of material from the bottom.

Studies of Sedimentary Matter Fluxes along a Long-Term Transoceanic Transect in the North Atlantic and Arctic Interaction Area

New data are presented on sedimentary matter fluxes and its main components along a meridional transect (59°30′ N) in the North Atlantic under the effect of multidirectional transport of water masses. The material for the study was collected July 2015 to July 2017 using sediment traps installed as parts of four automatic deep-water sedimentary observatories. In the subsurface layer, the annual variation in fluxes and composition of sinking material are determined by primary production. Bottom sedimentary material fluxes on the slopes of the Reykjanes Ridge are formed under conditions of transport of water masses and, accordingly, suspended particulate matter to the southwest along the ridge from the Iceland–Faroe and Greenland–Iceland rises. There is back transfer of material at the foot of the European continental slope. Sinking material is dominated by the biogenic component, the proportion of which decreases with depth due to dissolution and to less biological activity in the upper layer in winter. The role of lithogenic material is maximum in the bottom layer, where material is additionally supplied from the bottom.

Dynamics of the main components of fluxes of sedimentary matter in the White Sea

The results of long-term investigations in a small sea of the Arctic Ocean served as a basis for revealing new regularities characteristic of the sedimentary process in the Subarctic and Arctic zones. The monthly, seasonal, and multiyear dynamics of the main components of dispersed sedimentary matter fluxes are analyzed by defining the marine sedimentation stage. It is shown that the biogenic constituent of the flux decreases by an order of magnitude at its transition from dispersed to concentrated forms. The average values of the vertical flux are calculated including the total sedimentary matter and the contribution of main biogenic and terrigenous components per m2 of the bottom and the entire deep area of the White Sea.

Geochemistry of dispersed sedimentary matter and its fluxes in the water column of the Caspian Sea

The first data on the chemical composition of dispersed matter from sedimentary traps are reported. The suspended components of sedimentary matter (amorphous silica, organic matter, carbonates, and lithogenic material, as well as Fe, Mn, and minor elements) are considered. As a result, it is shown that the intraannual variability in vertical fluxes of sedimentary matter is characterized by a seasonal increase in spring and autumn. The high fluxes of the components of sedimentary matter on the northern and southern slopes of the Derbent Basin in winter are explained by precipitation of material from the nepheloid layer that forms over the contour current.

Comparative study of vertical suspension fluxes from the water column, rates of sedimentation, and absolute masses of the bottom sediments in the White Sea basin of the Arctic Ocean

A new approach using dispersed organic matter of the water column in sedimentation traps in comparison with the surface layer of the bottom sediments is applied for the study of marine sedimentation. This approach provides the opportunity for an in situ (by fluxes of sedimentary matter in the water column) study of modern sedimentation in the surface layers of the bottom sediments and tracing the changes in the environment and climate at a new technological level. This also allows us to choose the reverse task: to reconstruct the fluxes of the matter and chemical elements in ancient seas by the rates (or absolute masses) of sedimentation.

Seasonal variation of fluxes of dispersed sedimentary matter in the White Sea (Arctic ocean basin)

The monthly and seasonal quantity estimates of vertical fluxes of sedimentary matter from the White Sea performed during studies are the basis for the direct calculations of incoming chemical components, minerals, and various pollutants to the surface layer of bottom sediments. The White Sea, one of six Russian Arctic seas, may be considered as a megapolygon for further modern research using the new regularities of arctic sedimentogenesis established. This study focuses on the development of new technologies for complex studies of marine water areas using underwater sedimentation observatories, regular observations onboard vessels, and satellite oceanological data. The first priority task is year-round monitoring along the Northern Sea Route.

Dispersed organic matter and its fluxes in oceans and seas from the example of the White Sea: Results of a 12-year study

Annual and long-term quantitative estimations of the vertical fluxes of sedimentary matter in the White Sea are the basis for direct calculations of the gain of chemical components and minerals and diverse pollution of the surface layer of the bottom sediments. The White Sea, one of six Russian Arctic seas, may be considered as a megapolygon for further modern study using the new mechanisms of Arctic sedimentogenesis discovered. This work is directed at elaboration of new technologies of complex study of seas using submarine sedimentation and regular vessel observatories. The first priority task is year-round monitoring along the Northern Sea route.

The MSL-110 small sediment trap

A simple construction of the MSL-110 sediment trap developed at the Laboratory of Physical-Geological Research of the Shirshov Institute of Oceanology, Russian Academy of Sciences, is presented. The trap is easily assembled from standard parts available at stores. The trap is easy to use, reliable, and inexpensive. It is applied for determination of sedimentary matter fluxes and their components in water columns of seas, lakes, and other water reservoirs.

Sedimentation rates in the sea of Azov inferred from 137Cs and 241Am specific activity

The sedimentation rate is an important factor influencing the quantitative distribution and composition of sedimentary material, the thickness of bottom sediments, and the dynamics of their transformation at the early diagenesis stage [1]. In [2‐4], the average sedimentation rates were largely determined for the entire Sea of Azov using calculation methods (balance method and comparison between bathymetric charts). At the same time, subsequent natural and anthropogenic changes that occurred in the Don and Kuban river basins resulted in reorganization of the structure and dynamics of water masses, salinity, and sedimentary matter fluxes. In this connection, additional study of the spatial distribution and dynamics of sedimentation rates by advanced methods is needed. During several expeditions conducted in 2006 and 2007, bottom sediments were taken by a gravity corer (designed by the State Oceanographic Institute) and sampled in the layer-by-layer manner at ten stations located in the Russian segment of the Sea of Azov and mouth areas of the Don and Kuban rivers. The maximal length of cores is 100 cm [5]. In total, the activity of 137 Cs and 241 Am radionuclides was measured in over 60 samples. Technogenic radionuclides presently contained in

Sedimentary matter fluxes in the contour current sedimentation system over the continental slope of the Norwegian Sea

The sedimentation system of the bottom contour current over the continental slope of Bear Island in the Norwegian Sea is considered. The nepheloid layer that provides the high horizontal flux of sedimentary material represents the main source of matter for the bottom sediments. The vertical particulate matter flux is largely formed in the nepheloid layer; the flux from higher layers of the water column is insignificant. Horizontal and vertical fluxes of sedimentary matter show a positive correlation. The flux of the matter from the bottom sediment into the nepheloid matter and the residence time of particles in the latter are estimated.

The nepheloid layer and horizontal sedimentary matter fluxes in the Norwegian Sea

In this paper, the results of long-term studies of the nepheloid layer in the Norwegian Sea in the Komsomolets test area are considered. Its principal characteristics such as its thickness, the particulate matter concentration in the nepheloid layer, and its standing crop are presented. The nepheloid layer is formed by the near-bottom current, which, together with the particulate standing crop, determines the horizontal flux of the sedimentary matter over the continental slope. Also presented are data about the currents in different years of observations as well as estimates of the horizontal fluxes.

Supply and precipitation of hydrothermal iron in the rift valley of the Mid-Atlantic Ridge at 26° and 29° N

This publication considers the probing data on aquatic anomalies (hydrothermal plumes) in the areas of 26° and 29° N of the Mid-Atlantic Ridge (MAR). The mass of the hydrothermal iron supply and the intensity of the iron sedimentation onto the bottom were estimated by means of sediment traps. It was found that the plume of the TAG hydrothermal vent 6 km3 in volume contained about 67 t of suspended Fe; the plume of the Broken Spur field (up to 8.24 km3 in volume) contained 23.5 t or less because of the lower concentration. The data on the sedimentary matter fluxes showed that 0.3–0.5% of the hydrothermal iron was precipitated immediately from a plume of neutral buoyancy onto the bottom; the bulk of the iron was dissipated into the environment. From the dimensions of the plumes, the flow dynamics, the iron concentrations in the plumes, and the amounts of iron supplied by hydrothermal vents, it was found that the resident time of the plumes considered was from 5 to 10 days.

Hydrological properties, suspended matter, and particulate fluxes in the water column of the Bear Island Trough

The CTD and nephelometric sounding data are considered along with the parameters of the nearbottom currents and particulate fluxes measured by a subsurface mooring station in the northern part of the Bear Island Trough. It is shown that the near-bottom current is characterized by highly variable parameters, while the distribution of suspended particulate matter demonstrates surface and bottom maximums. The horizontal and vertical fluxes of sedimentary matter in the nepheloid layer are studied.