499 Chapter 28 Dynamics of Redox-Sensitive Elements Ami Nishri and Ludwik Halicz T. Zohary et al. (eds.), Lake Kinneret, Ecology and Management, Aquatic Ecology Series 6, DOI 10.1007/978-94-017-8944-8_28, © Springer Science+Business Media Dordrecht 2014 A. Nishri () The Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic & Limnological Research, P.O. Box 447, 14950 Migdal, Israel e-mail: nishri@ocean.org.il L. Halicz Geological Survey of Israel, 30 Malkhe Israel St., 95501 Jerusalem, Israel e-mail: ludwik@gsi.gov.il Abstract Following the onset of stratification in spring, the interaction between the oxy-anions of Mo, U, and Sb with reduced solutes in Lake Kinneret lower water mass (LWM) causes the removal of part of these redox-sensitive elements. How- ever, the removal is shown here to occur also during the de-stratification stage in autumn in both the top of the HS − , Fe oxide, and Fe(II) enriched LWM and a thin partially mixed layer above it. This process is shown to be associated with the fast thermocline deepening and induced by enhanced sedimentation of organic matter and Fe–Mn oxides. The primary source of this matter is hypothesized to be the resus- pension of sediments deposited at those lake floor areas which become exposed to the intensive water motions in the upper layers due to thermocline deepening. The present chapter describes the effect of physical and biogeochemical regime across the mid-water temperature transition layer on the removal of redox-sensitive ele- ments such as Mo, U, Sb, and Se. Keywords Buoyancy mixing · Redox · Lower water mass · Manganese · Molybdenum · Selenium · Antimony 28.1 Introduction For many years, the research on geochemical processes of trace elements in Lake Kinneret was focused on elements which were shown to affect biological processes in the euphotic layer. Notably of these were iron (Berman et al 1993; Sivan et al 1998; Shaked 2002), copper (Frevert et al. 1982; Wynne and Pieterse 2000), and selenium (Lindström and Rhode 1978; Lindström 1982, 1983; Nishri et al. 1999).