Investigation of biogeochemical processes in sediment microniches using sandwich sensor technique
We hypothesize that (1) a significant fraction of diagenetic activity in sediments is associated with reactive organic aggregates that create a specific geochemical environment (called microniches), (2) sediments are better approached as dynamic heterogeneous mosaic of microniches rather than as homogeneously stratified layers of activity, and (3) oxygen sensitive elements including Fe, Mn, Co, As and Sb are primarily mobilized in or close to these microniches. This work will use a combined sandwich sensor that allows, for the first time, at the same location, fine-scale quantitative 2-D images of trace elements mobilization as well as geochemical variables associated with organic matter mineralization (O2, pH, H2S). The main goal of this research project is to unravel and to better understand biogeochemical cycles of trace elements influenced by organic matter deposition and variations of pH and O2 concentrations in microniches in aquatic sediments. By using well-defined experimental systems and a production-consumption mass balance model, we will explore the quantitative relationship between trace element release and respiration. The outcomes of this work will provide a major improvement in our understanding of metal dynamics in sediment ecosystems.
Belgian Coastal Zone (North Sea, Belgium) and China
Laser Ablation-ICP-MS, DGT, O2/pH planar optode, Arsenic, Selenium, Antimony, microniches