caa a22 4500 465761992 CHVBK 20180323111901.0 cr unu---uuuuu 170327e19900301xx s 000 0 eng 10.1007/BF00878241 doi (NATIONALLICENCE)springer-10.1007/BF00878241 Biogeochemistry of iron in an acidic lake [Elektronische Daten] Dedicated to Werner Stumm for his 65th birthday [Barbara Sulzberger, Jerald Schnoor, Rudolf Giovanoli, Janet Hering, Jürg Zobrist] In this paper, the fate of iron in Lake Cristallina, an acidic lake in the Alps of Switzerland, is discussed. A simple conceptual model is developed in order to explain the observed diel variation in dissolved iron(II) concentration. Biotite weathering provides reduced iron that is oxidized and subsequently precipitated in the lake. The amorphous Fe(III)hydroxide (FeOOH ⋅xH2O), found in the sediments of Lake Cristallina, is an Fe(II) oxidation product. This oxygenation reaction is most probably catalyzed by bacteria surfaces, as indicated by the relatively high estimated oxidation rate compared to the oxidation rate of the homogeneous oxidation of inorganic Fe(II) species at the ambient pH of Lake Cristallina (pH 5.4 at 4 °C) and by the scanning electron micrograph pictures. Under the influence of light, these amorphous iron(III)hydroxide phases are reductively dissolved. The net concentration of Fe(II) reflects the balance of the reductive dissolution and the oxidation/precipitation reactions and tends to parallel the light intensity, leading to a diurnal variation in the Fe(II) concentration. The rate of the photochemical reductive dissolution of Lake Cristallina iron(III)hydroxides is greatly enhanced in situ and in the laboratory by addition of oxalate to the lake water. Birkhäuser Verlag, 1990 Acidic lake nationallicence biogeochemistry of iron nationallicence diurnal variation nationallicence iron(II) oxidation nationallicence iron(III) reduction nationallicence light induced dissolution nationallicence weathering nationallicence Sulzberger Barbara Institute for Water Resources and Water Pollution Control (EAWAG/ETH, CH-8600, Dübendorf, Switzerland aut Schnoor Jerald Department of Civil and Environmental Engineering, University of Iowa, Iowa City, USA aut Giovanoli Rudolf Laboratory of Electron Microscopy, Institute of Inorganic Chemistry, University Bern, Switzerland aut Hering Janet Institute for Water Resources and Water Pollution Control (EAWAG/ETH, CH-8600, Dübendorf, Switzerland aut Zobrist Jürg Institute for Water Resources and Water Pollution Control (EAWAG/ETH, CH-8600, Dübendorf, Switzerland aut Aquatic Sciences Birkhäuser-Verlag 52/1(1990-03-01), 56-74 1015-1621 52:1<56 1990 52 27 https://doi.org/10.1007/BF00878241 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00878241 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sulzberger Barbara Institute for Water Resources and Water Pollution Control (EAWAG/ETH, CH-8600, Dübendorf, Switzerland aut NATIONALLICENCE 700 1- Schnoor Jerald Department of Civil and Environmental Engineering, University of Iowa, Iowa City, USA aut NATIONALLICENCE 700 1- Giovanoli Rudolf Laboratory of Electron Microscopy, Institute of Inorganic Chemistry, University Bern, Switzerland aut NATIONALLICENCE 700 1- Hering Janet Institute for Water Resources and Water Pollution Control (EAWAG/ETH, CH-8600, Dübendorf, Switzerland aut NATIONALLICENCE 700 1- Zobrist Jürg Institute for Water Resources and Water Pollution Control (EAWAG/ETH, CH-8600, Dübendorf, Switzerland aut NATIONALLICENCE 773 0- Aquatic Sciences Birkhäuser-Verlag 52/1(1990-03-01), 56-74 1015-1621 52:1<56 1990 52 27 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer