Composition of suspended matter and bottom sediments from the North Dvina mouth area

Grain-size, mineral and chemical compositions of suspended particulate matter (SPM) from waters of the Severnaya (North) Dvina River mouth area during the spring flood in May 2004 is studied. Data published on composition of riverine SPM in the White Sea basin are very poor. The spring flood period when more than half of annual runoff is supplied from the river to the sea in during short time is understood more poorly. The paper considers comparison results of the grain size compositions of SPM and bottom sediments. Data of laser and hydraulic techniques of grain size analysis are compared. Short-period variations of SPM concentration and composition representing two diurnal peaks of the tide level are studied. It is found that SPM is mainly transferred during the spring flood as mineral aggregates up to 40 µm diameter. Sandy-silty fraction of riverine SPM settles in delta branches and channels, and bulk of clay-size material is supplied to the sea. Mineral and chemical compositions of SPM from the North Dvina River are determined by supply of material from the drainage basin. This material is subjected to intense mechanic separation during transfer to the sea. Key regularities of formation of mineral composition of SPM during the flood time are revealed. Effect of SPM grain size composition on distribution of minerals and chemical elements in study in the dynamic system of the river mouth area are characterized.

Lignin and chemical elements in the surface layer of bottom sediments from the Kandalaksha Bay of the White Sea

Chemical composition of the upper layer of sediments (0-1 cm) in the Kolvits and Knazhaya inlets, and also in the deep-water part of the Kandalaksha Bay is considered. It is shown that silts are richer in Fe, TOC, and heavy metals, than sands. The highest concentration of these elements is found in sediments under mixing zones of riverine and sea waters. Correlations of P, Zn, Cd, and Cu with iron are high, and correlations of Pb and Cu with organic carbon are also high. Very high concentration of Pb in the Kandalaksha Bay indicate technogenic pollution of sediments. Lignin makes significant contribution to formation of organic matter in the sediments. Composition of lignin in bottom sediments of the Kandalaksha Bay is defined by composition of lignin in soils and aerosols. Vanillin and syringyl structures prevail in molecular composition of lignin in bottom sediments. Their sources are coniferous vegetations, soils, and mosses. Ratios of certain types of phenol compounds indicate pollution of the upper layer of sediments by technogenic lignin. Lead and copper correlate well with this technogenic lignin.

Stable carbon isotope record of planktonic foraminifera and organic matter from sediment cores in the Gulf of Aqaba

The stable carbon isotopic composition of the planktonic foraminifera Globigerinoides sacculifer and G. ruber (white) and sedimentary organic matter from the northern Gulf of Aqaba have been investigated to estimate changes in delta13CDIC in surface waters during the last 1,000 years. The high sedimentation rates at the core sites (about 54 cm/Kyear) provide high temporal resolution (~10 years). Recent sediments at the top of the cores reflect conditions younger than 1950. The delta13C records of the planktonic foraminifera from three multicores display similar trends, showing a uniform and consistent pattern before the 1750s, and a gradual decrease of approximately 0.63? over the last two centuries. This decrease seems to track the decrease of delta13CDIC in surface waters, which is mainly caused by the increase of anthropogenic input of 13C-depleted CO2 into the atmosphere. Similarly, a trend towards lighter values of the carbon isotopic composition of sedimentary organic matter (delta13Corg) during the last 200 years supports the interpretation obtained from the planktonic foraminiferal delta13C. Furthermore, direct measurements of seawater show that delta13C of the dissolved inorganic carbon (DIC) in the northern Gulf of Aqaba has decreased by about 0.44 per mil during the period 1979-2000. The average annual decrease is 0.021 per mil, which is similar to that observed globally. The delta13C values of planktonic foraminifera combined with organic matter delta13C from marine sediments are good indicators for reconstructing past changes in atmospheric CO2 concentrations from the northern Gulf of Aqaba.

Zooplankton abundance and biomass along transects seaward from the coastline of the White Sea in August 2006 and 2007

Distribution patterns of water temperature, salinity, current velocities, suspended matter concentration, bottom contour, and zooplankton abundance were studied in relation to marine-riverine interactions and tide/ebb phases for coast lines of different configurations in the White Sea during cruises of R/V Ekolog (August of 2006 and 2007). Significant difference in manifestation of combined effect of marine and riverine impacts (estuarine concave relief) and only marine impact (open-sea straight line portion) was observed. This results in both variations in sea water level and distribut patterns of suspended matter and zooplankton.

(Table 2) Contents of trace elements in plankton from the White Sea

With a view to more complete understanding of the role of phyto- and zooplankton in biogeochemical cycles, spatial distributions of Fe, Mn, Co, Ni, Cr, Cu, Cd, Pb, Zn, As, Hg, and Corg in the White Sea seston (21 samples) collected in August 2004 during Cruise 64 of R/V ''Professor Shtokman'' were studied. It was shown that the elements in study are accumulated in plankton with enrichment factors from 10**2 for Hg to 10**5 for Fe, as compared to seawater. Spatial distribution of trace elements is determined by sources of their supply and correlates with distribution of primary production and biomass of zooplankton. Increased values of trace element contents (excluding As) are characteristic of the Dvina Bay, whereas the highest As concentrations were found in the Kandalaksha Bay.

Mineral and chemical composition of surface bottom sediments from the Onega Bay, White Sea

The distribution of temperature and salinity, current velocities, suspended particulate matter, bottom sediments, bottom morphology, and planktonic and benthic organisms during the summer period are studied in the estuary of the large Onega River and coastal areas of the Onega Bay (White Sea) influenced by interacting marine and riverine factors.

(Table 1) Concentrations of organic carbon in bays of the White Sea

Analysis of contribution of micronodules of sand and silt size to chemical composition of various types of pelagic sediments, as well as use of published data indicate that in some types of bottom sediments micronodules are the principal carriers of manganese and nickel. These elements appear to constitute smaller fractions of colloidal iron and manganese hydroxides, as well as terrigenous material.