Iron, sulfur and arsenic biogeochemistry in an acid-sulfate wetland: new insights from a landscape-scale experiment

Iron sulfide oxidation in drained coastal lowland soils liberates acidity, Fe and SO4, and leads to the accumulation of secondary Fe(III) minerals, such as schwertmannite and jarosite. In this seminar, I will describe recent advances in understanding iron, sulfur and arsenic biogeochemistry in acid-sulfate wetland soils. In particular, I will discuss new discoveries from the world's first landscape-scale reflooding of a tidal acid-sulfate wetland. In addition to field observations, the presentation will also include a discussion of new findings from controlled laboratory-based experiments examining sorption-desorption of arsenic and transformations of iron-sulfur in model wetland systems. This will be linked to field observations on the formation and transformation of iron-sulfide minerals, including greigite and pyrite, and the impact on in-situ arsenic behaviour.

• Announcement (pdf)