The role of mineral compounds and chemical conditions in the binding of phosphate in the Ems estuary |
| |
Authors: | V N De Jonge M M Engelkes |
| |
Institution: | (1) Rijkswaterstaat, National Institute for Coastal and Marine Management, P. O. Box 207, 9750 AE HAREN (GN), The Netherlands;(2) Department of Marine Biology, University of Groningen, P.O. Box 14, 9750 AA HAREN (GN), The Netherlands |
| |
Abstract: | In the Ems estuary the gradients in dissolved phosphorus and iron are non-conservative and opposite. The relations between
different mineral compounds, environmental conditions and phosphate concentrations were studied, in an attempt to explain
this. Laboratory experiments on water samples from the reaches with high concentrations of phosphate and of suspended matter
revealed a low concentration of calcite-bound phosphorus in the middle reaches of the estuary (only 0.07%). Therefore, it
is concluded that calcite possibly plays only a modest role in phosphate distribution in the Ems estuary. Further experiments
revealed that nearly 70% of the particulate inorganic phosphorus is iron-bound. It is demonstrated that organic coatings on
minerals inhibit phosphate release at a low redox potential. Moreover, the organic matter itself contained c. 20% of particulate
phosphorus. Approximately 10% of the particulate phosphorus may be associated with clay minerals. It is concluded that in
addition to biological processes, the phosphorus associated with ironoxyhydroxides may be crucial for the seasonal variation
of the phosphate concentrations in the water. |
| |
Keywords: | phosphate adsorption iron oxyhydroxide pH calcite organic matter clay minerals Ems estuary |
本文献已被 SpringerLink 等数据库收录! |
|