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The aim of this study was to identify and quantify lignin transported from the River Vistula to the accumulation area in the Gdańsk Basin. Sediment samples collected along the Vistula mouth –Gdańsk Deep transect were analysed for lignin. Lignin was characterised by oxidative degradation, cupric oxide being chosen as the most suitable oxidising agent. The polar functional groups of the oxidation products were silylated and the derivatives analysed by capillary gas chromatography on fused capillary silica columns with flame ionisation detection. Lignin-derived oxidation products were quantified in the range from 3 to 20 μg g−1 dry wt. for phenolic acids and from 6 to 12 μg g−1 dry wt. for phenolic aldehydes. Differences in oxidation products contents are assigned to different lignin sources in the marine environment. The horizontal and vertical gradients of these compounds in the sediments of the Gdańsk Basin are documented. The results are discussed in terms of the origin and fate of organic matter in the Gdańsk Basin. The measured differences in quality and quantity of the identified oxidation products provide insight into diagenetic processes in the surface marine sediments.
The distribution of Ca, Mg, K, Na, Si, P, S, Al, V, Mn, Fe, Co, Cu, Ni, Zn, Sr, Mo, Cd, Sb, As, Bi, Pb, Tl, Th, U, Ti, Cr, Ba and REE (determined by ICP-MS, ICP-AES, XRF and AAS methods) in bottom sediments of the southern Baltic as well as the Vistula and Szczecin Lagoons were discussed. Based on enrichment factors (EFs) the accumulation of the chemical elements in surficial sediment with respect to their concentration in Earth’s crust showed that Cd, Pb, Cu, Zn and Ag in coastal regions seem to be generally anthropogenic in origin. It is shown that the sediments of the Szczecin Lagoon are the most polluted by heavy metals, especially Cd, Zn and Pb, and that the degree of heavy-metal pollution decreases substantially on passing from the Szczecin Lagoon to the Pomeranian Bay and then on passing to the Bornholm Deep and Słupsk Furrow. Fluffy material from the Oder estuary appears to be the main source of heavy metals in the muddy sediments of the Bornholm Deep. The distribution of the rare earth elements (REE) in sediments of the Polish EEZ is more complex than previously thought and may be controlled by the input of Fe-organic colloids from rivers and the presence of detrital material in the sediments. The rare earth element (REE) patterns in sediments from the study region do not appear to have been greatly modified during transport from their source into the southern Baltic. In each of the study areas, there is a slight enrichment in the LREE relative to the HREE in the sediments compared to the NASC. The lack of significant anomalies for the redox-sensitive elements such as Ce and Eu implies that redox processes have marginal significance in modifying the distribution of the REE in the sediments studied. Chemometric techniques (FA, EMA) appeared to be useful for interpreting the spatial differences of chemical element concentrations in the study area.
Wind, flow and wave measurements were performed in November–December in 2008 in the relatively narrow and shallow Suur Strait connecting the waters of the V¨ainameri and the Gulf of Riga. During the measurement period wind conditions were extremely variable, including a severe storm on 23 November. The flow speed along the strait varied between ±0.2 m s−1, except for the 0.4 m s−1 that occurred after the storm as a result of the sea level gradient. The mean and maximum significant wave heights were 0.53 m and 1.6 m respectively. Because of their longer fetch, southerly winds generated higher waves in the strait than winds from the north. All wave events caused by the stronger southerly winds induced sediment resuspension, whereas the current-induced shear velocity slightly exceeded the critical value for resuspension only when the current speed was 0.4 m s−1. A triplenested two-dimensional high resolution (100 m in the Suur Strait) circulation model and the SWAN wave model were used to simulate water exchange in 2008 and the wave-induced shear velocity field in the Suur Strait respectively. Circulation model simulations demonstrated that water exchange was highly variable, that cumulative transport followed an evident seasonal cycle, and that there was an gross annual outflow of 23 km3 from the Gulf of Riga. The horizontal distribution of waveinduced shear velocity during the strong southerly wind event indicated large shear velocities and substantial horizontal variability. The shear velocities were less than the critical value for resuspension in the deep area of the Suur Strait.
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