Identification of stoichiometric iron-phosphorus colloids produced in a eutrophic lake

Article Article scientifique Article Identification of stoichiometric iron-phosphorus colloids produced in a eutrophic lake eng 1999 author Lienemann Charles-Philippe author Monnerat Marc 45030 author Dominik Janusz 22088 author Perret Didier 22934 133-149 10.1007/s000270050058 1015-1621 http://link.springer.com/10.1007/s000270050058 Iron-rich colloids formed at the oxic-anoxic interface of a eutrophic lake (Lake Lugano; CH) were characterized by bulk chemical methods and analytical electron microscopy. Fractionation of raw waters showed that non-dissolved iron is particulate above the oxicline and mainly colloidal in the anoxic part of the hypolimnion, while non-dissolved ortho-phosphate is mostly colloidal through the water column. Because of these differences, filtration did not prove helpful for the determination of the role of iron-rich species in the scavenging of ortho-phosphate. On the other hand, analytical electron microscopy revealed that iron-rich nano-granules (ca. 50nm) are associated to the surface of bacterially produced fibrillar polysaccharides. Iron colloids in these complex entities contain important and constant amounts of phosphorus ([PO4]part:[Fe]part = 0.48 ± 0.11, n = 1096 Fe-rich entities analyzed by electron microscopy), which suggests that phosphates are stoichiometrically incorporated into the hydrous iron oxide phase, with a tentative composition Fe2[OOH]1-x[(OH)3]x[PO4], during its genesis. Aquatic colloids Iron Phosphorus Stoichiometric composition Nutrient scavenging Electron microscopy Dewey 550 41 Département F.-A. Forel des sciences de l'environnement et de l'eau 153 false Aquatic sciences 61 2 8111740c-71ad-4079-bc69-a013031c36e0 Article (Published version) Public Lienemann_AS_199961133.pdf 591770 application/pdf OA NATIONAL openAccess Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département F.-A. Forel des sciences de l'environnement et de l'eau

Title	Published in	Access level	OA Policy	Year	Views	Downloads

Identification of stoichiometric iron-phosphorus colloids produced in a eutrophic lake	Aquatic sciences			1999	187	339

Archive ouverte UNIGE

Monnerat, Marc