Mud-water exchange of phosphate and other ions in undisturbed sediment cores and factors affecting the exchange rates
Archiv für Hydrobiologie Volume 73 Number 2 (1974), p. 218 - 237
published: Apr 9, 1974
ArtNo. ESP141007302006, Price: 29.00 €
The exchange rates of phosphorus, nitrogen and to a lesser extent iron, calcium and silicate across the sediment surface have been determined by experiments with undisturbed sediment cores from the profundal of a spectrum of Danish lakes. The effects of oxidation state, antibiotics and pH on the exchange rates have been studied and attempts are made to relate the exchange to sediment parameters. The nitrogen exchange involves mineralisation, nitrification and denitrification and occurs by biological processes. When oxygen is present the phosphate exchange is governed by adsorption, but microorganisms also seem to be involved. Under anaerobic conditions the phosphate release is linearly dependent on the concentration gradient across the mud surface and the exchange may be explained in terms of diffusion with a diffusion coefficient of 0.6 X 10-6 X cm² X S-1. The adsorption and the concentration gradient are influenced by a pH-dependent dissolution and precipitation of calcium and iron phosphates.