Early diagenetic processes generate iron and manganese oxide layers in the sediments of Lake Baikal, Siberia

Research at Lake Baikal reveals that distinct iron and manganese oxide layers buried within sediments arise from early diagenetic processes, creating complex redox gradients. The study demonstrates that the dissolution of these oxides is closely linked to anaerobic methane oxidation (AOM), either through sulfate reduction or direct iron reduction, leading to sharp mineral boundaries in sediment cores. Additionally, anaerobic nitrification of ammonium was observed as an alternative pathway for Mn(IV) dissolution. Using filter tube samplers and portable capillary electrophoresis, the study elucidates the sequence of biogeochemical processes responsible for the formation, transformation, and dissolution of these layers, while also discussing their implications for sediment patterns and redox discontinuities.

Torres, N. T., Och, L. M., Hauser, P. C., Furrer, G., Brandl, H., Vologina, E., Sturm, M., Bürgmann, H., & Müller, B. (2014). Early diagenetic processes generate iron and manganese oxide layers in the sediments of Lake Baikal, Siberia. Environ. Sci.: Processes Impacts, 16(4), 879–889. https://doi.org/10.1039/c3em00676j