6c254407-d708-407e-a92f-24906cffbb71 urn:uuid eng UTF-8 nonGeographicDataset nonGeographicDataset 2025-10-16T04:52:30 creation ISO 19115 2016 The Biogeochemistry of Iron 6c254407-d708-407e-a92f-24906cffbb71 For our understanding of interactions between living organisms and the solid earth it is fascinating to investigate the reactivity of iron at the interface of the bio- and geosphere. Similar to manganese (chapter 11) iron occurs in two valence states as oxidized ferric iron, Fe(III), and reduced ferrous iron, Fe(II). Two principal biological processes are of importance: Microorganisms such as magnetotactic bacteria and phytoplankton (see chapter 2 and section 7.3) depend on the uptake of iron as a prerequisite for their cell growth (assimilation). Others conserve energy from the reduction of Fe(III) to maintain their metabolic activity (dissimilation). In this case ferric iron serves as an electron acceptor which is also termed oxidant. Apart from biotic reactions manifold abiotic reactions occur depending on thermodynamic and kinetic conditions. Due to redox-reactions dissolution and precipitation of iron-bearing minerals may result which has great influence on the sorption/desorption and co-precipitation/release behavior of various components such as phosphate and trace metals. From a geologic point of view it is striking to find discrete iron enriched layers such as black shales or strata of the banded iron formation, which challenge geochemists to reconstruct the environmental conditions of their formation. Article Earth Sciences External Publication Published_External Related Product documentDigital View the online description of the publication Marine Geochemistry, 2nd Edition by Schulz, H.D. & Zabel, M. (editors) HTML Unnamed resource documentDigital HTML