Impact of electrogenic sulfur oxidation on trace metal cycling in coastal sediments. (FWOTM736)

The release of trace metals from natural and contaminated marine sediments to the overlying water can have important implications for aquatic ecosystems. Recently, a novel pathway of sulfur oxidation has been discovered in marine sediments, whereby long filamentous bacteria are capable of coupling redox half-reactions over centimeter scales. This process, referred to as electrogenic sulfur oxidation (ESOx), has been shown to occur globally in coastal systems. Preliminary results from laboratory experiments indicate that ESOx induces strong pH gradients in sediments, and hence, it has the potential to strongly influence the remobilization of trace metals in coastal sediments. This can have a strong impact on coastal ecosystems, but the magnitude and risk of trace metal remobilization are yet unknown. In response, this FWO project proposes an in depth investigation of trace metal cycling in sediments where ESOx is present. In a first phase, we will employ state-of-art- techniques in analytical chemistry combined with reaction transport modelling to determine the trace metal speciation in laboratory sediment incubations where ESOx is induced. In a second stage, we will examine trace metal cycling at a natural field site (Station 130 in front of Belgian coast, the first location worldwide where ESOx was demonstrated to occur under natural conditions). Overall, this study should greatly improve our quantitative understanding of trace metal remobilization in coastal environments.

Keywords:Chemistry

Disciplines:Physical chemistry not elsewhere classified