The role of mineral compounds and chemical conditions in the binding of phosphate in the Ems estuary
De Jonge, V.N.; Engelkes, M.M. (1993). The role of mineral compounds and chemical conditions in the binding of phosphate in the Ems estuary. Neth. J. Aquat. Ecol. 27(2-4): 227-236. https://dx.doi.org/10.1007/BF02334786
In: Netherlands Journal of Aquatic Ecology. Kluwer Academic Publishers/Netherlands Society of Aquatic Ecology: Bilthoven. ISSN 1380-8427; e-ISSN 2214-7098, more
Also appears in:Meire, P.; Vincx, M. (Ed.) (1993). Marine and estuarine gradients: ECSA 21: Proceedings of the 21st symposium of the Estuarine and Coastal Sciences Association held in Gent, 9-14 september 1991. Netherlands Journal of Aquatic Ecology, 27(2-4). Netherlands Society of Aquatic Ecology: Bilthoven. 496 pp., more
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| Keywords |
Marine/Coastal; Brackish water |
| Authors | | Top |
- De Jonge, V.N., more
- Engelkes, M.M.
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| 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% Qf 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. |
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