Dynamics of redox-sensitive elements

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. However, 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 resuspension 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 elements such as Mo, U, Sb, and Se.