Marine Biogeochemistry

Sediment and pore fluid analyses

Thousands of sediment and water samples are processed and analyzed each year in the geochemical laboratories of research unit Marine Geosystems. 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.

In our laboratories for sediment and water analysis, we determine the composition of seawater, sediments, pore water and authigenic precipitates (carbonates, barites, gas hydrates). 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

Magnesium

Nitrate

Nitrite

pH-Value in the sediment

Phosphate

Oxygen