Phytoplankton-Mediated Redox Cycle of Iron in the Epilimnion of Lake Kinneret

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• 作者：Yeala Shaked ; Yigal Erel ; and Assaf Sukenik
• 刊名：Environmental Science & Technology
• 出版年：2002
• 出版时间：February 1, 2002
• 年：2002
• 卷：36
• 期：3
• 页码：460 - 467
• 全文大小：123K
• 年卷期：v.36,no.3(February 1, 2002)
• ISSN：1520-5851

文摘

The biological-mediated redox cycle of Fe was studied inthe epilimnion of Lake Kinneret (Sea of Galilee), amesotrophic lake in Israel. Multi-annual lake watersampling and incubation experiments were carried out tostudy Fe(III) reduction by natural phytoplankton populationsand their possible role in inhibiting Fe(II) oxidation.The reduction characteristics of the dinoflagellate Peridiniumgatunense, the dominant lake alga, were further examinedin the laboratory. The steady-state concentration of Fe(II) calculated from the assessed reduction and oxidationrates was compared with Fe(II) measured in the lake inorder to evaluate the significance of these processes to thelake Fe redox cycle. Nanomolar concentrations of Fe(II)were measured in the oxygenated, high pH, upper waterlayer of the lake throughout the year. Reduction rates of Feby natural phytoplankton assemblages ranged between0.1 and 10 nM/h. The highest reduction rates, determinedin dinoflagellate-dominated lake waters, coincided withthe highest concentrations of Fe(II) measured simultaneouslyin the lake. Iron(II) oxidation rates calculated from themeasured lake Fe(II) and the obtained reduction rates weresignificantly slower than published abiotic Fe(II) oxidationrates. Indeed, Fe(II) oxidation rates measured in algal-enriched lake water were 30-fold slower than Fe(II) oxidationrates in natural water, demonstrating the potential forFe(II) stabilization by the lake phytoplankton.