The chemical composition of seawater, pore water, marine sediments, authigenic precipitates, gas hydrates and other solids is analyzed in the water and sediment laboratories. Sediments are dried, pulverized and digested in acid mixtures before analysis. In addition to the elements (Li, Na, K, Mg, Ca, Sr, Ba, Ti, V, Mo, Mn, Fe, Ni, Cu, Zn, B, Al, C, Si, N, P, S, Cl, Br, I), various species and nutrients (methane, ethane, propane, sulphate, chloride, bromide, iodide, sulphide, phosphate, silicic acid, ammonium, nitrate, nitrite, pH, alkalinity, dissolved inorganic carbon, particulate organic carbon, carbonate, pyrite, Fe(II)/Fe(III) ratios) are determined. The following analytical devices and methods are used: optical ICP, ion chromatography, gas chromatography, CNS element analysis, polarography, photometry and various titrations.
Thousands of sediment and water samples are processed and analyzed each year in the geochemical laboratories of Benthic Biogeochemistry group. These labs provide basic geochemical data defining the background for more specialized and advanced studies. Sediments and other solids are digested in appropriate acids and analyzed for major and minor element contents using optical ICP. Major sediment components (organic carbon, total nitrogen, total sulfur, carbonate) are determined by element analysis. Pore waters are analyzed for dissolved nutrients (nitrate, nitrite, ammonia, silica, phosphate), anions (sulfate, sulfide chloride, bromide, iodide) and elements (Li, Na, K, Mg, Ca. Sr, Ba, B, Mn, Fe) using photometry, ion-chromatography and optical ICP, respectively. Moreover, we determine ferric/ferrous iron ratios in various fluids with polarographic techniques and apply titration methods to determine total alkalinity and chloride concentrations in pore fluids. Many of our instruments and techniques are also used during marine expeditions on board of different research vessels.
Methods on board
FE-Extraktion and Determination
Methods / Laboratories
