Particle size-related phosphate binding and P-release at the sediment–water interface in a shallow German lake

Issue Title: Part I: Sediment-Water Interaction 13 Part II: Salt Ecosystems Section Phosphate binding and P-release in the sediment of the eutrophic shallow Lake Bützow are described based on sediment profiles, particle size fractions and incubation experiments. Total phosphorus was about 15% higher in the upper 0.5 cm layer than in the 0.5-1 cm layer. Phosphorus binding varied with sediment depth. Hot P^sub [arrow right]NaOH^ and P^sub [arrow right]HCl^ were the dominant fractions in all sediment horizons down to 10 cm depth, with values ranging from 20 to 30%. The P^sub [arrow right]H2O^, P^sub [arrow right]BD^, o-P^sub [arrow right]NaOH^ and nr-P^sub [arrow right]NaOH^ decreased with depth. The P^sub [arrow right]BD^ contributed 21% to Tot-P in the horizon 0-0.5 cm and decreased by half in 1-2 cm. The greatest proportion of particles (35%) was found in the 100-200 μm fraction. This size fraction also accumulated most of the phosphate. Moreover, P-forms were differently distributed in the various particle sizes of the sediment. Sediment particles