In this project we study the processes influencing iron and manganese cycling in boreal estuaries. Iron and manganese are two commonly occurring metals that take part in microbially mediated chemical reactions. As such, they are an important source of energy for microorganisms in a range of envrionments. Estuaries are transitional aquatic systems with strong gradients of salinity, oxygen and pH conditions, which influence the cycling of iron and manganese and hence their potential role in microbial processes.
Eutrophication, land use change and climate change are causing major disruptions in biogeochemical cycling in boreal estuaries today. In particular, the rapid accumulation of organic materials in estuarine sediments has stimulated microbial processes such as methanogenesis and altered the oxygen balance of coastal waters. Using geochemical analyses of both water column and sediments, we study the effects of these changes on the cycling of iron and manganese.