The marine environmental geochemistry of the southern Baltic Sea

• Main Author: Smith, Jason Alistair Christian
• Published: University of Edinburgh 1999
• Subjects: 551.9
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.662118

The initial focus of this research sought to investigate the marine geochemistry of radium and barium in order to elucidate upon the processes governing circulation patterns and residence times in the southern Baltic Sea. The project has since developed and transformed into a detailed study of the spatial and temporal distribution of a select group of metals, and in some respects pollutants, in the region north of the river Oder where it discharges into the Baltic Sea. A transect of progressively deepening water depths, thought to trace the major outflow of the river Oder into a depositional basin, were investigated over a period of 15 months. Four cruises during this time were undertaken to coincide with each season in order to investigate any broad scale seasonalities. This thesis looks at the main compartments and integrated processes associated with the sediment, nepheloid layer and the water column of this marine environment. This has been achieved by the use of coupled radionuclide and trace metal data followed by the calculation of fluxes and inventories for a select group of elements. Major and trace metals were analysed via ICPMS and XRF and radionuclides were measured by gamma ray spectrometry. Supporting data in the form of grain size analysis, XRD and carbon and nitrogen measurements were also made. Radium measurements were attempted using the Photo-Electron Rejecting Alpha Liquid Scintillation (PERALS) spectrometer system. Of particular interest Pb, Zn, and Sn and their enrichment over average shale in the Arkona Basin. Coupled with this, stable lead isotope data details a historical picture of increased pollution associated with the rise of the automobile and subsequent decline of lead with the advent of unleaded petrol in the mid eighties. In addition the significance of the mobile nepheloid layer is investigated as a primary transport and modification route for the elements of interest. This thesis challenges the traditional role and concept of the Arkona basin as a depositional site for the pollutants discharged from the river Oder and instead evaluates the depositional role of the Arkona Basin as being primarily a sink for the atmospheric input rather than that associated with riverine discharge.