Carbon and nitrogen content of transparent exopolymer particles (TEP) in relation to their Alcian Blue adsorption

The carbon and nitrogen content of transparent exopolymer particles (TEP) w as determined and related to the concentration of TEP as quantified by a co lorimetrical method. TEP were produced in the laboratory from dissolved pre cursors by laminar or turbulent shear. Dissolved precursors were obtained b y 0.2 mum filtration from diatom cultures, with or without nutrient reducti on, and from natural diatom populations. The relationship between carbon an d TEP was significant, linear and species-specific. Carbon concentration of TEP derived from this relationship concurred with previous findings, Short age of silicic acid or nitrate in the culture media had no effect on the ca rbon content of TER Molar C:N ratios of TEP were above the Redfield ratio, with a mean value of 26. It is suggested that the nitrogen fraction of TEP can be explained by adsorption of dissolved organic nitrogen (DON) onto TEP . Based on the newly established relationship, concentrations of TEP-derive d carbon (TEP-C) were calculated for the Baltic Sea, the coastal Pacific, t he North East Atlantic and the Northern Adriatic Sea.