In Aquatic Biogeochemistry Research Unit (ABRU), we study how the essential elements of life are cycled in water and sediment. In particular, we focus on carbon, nitrogen, phosphorus and silicon cycling. These are the key nutrients whose availability determine the distribution of life in Earth’s aquatic environments. We study the whole spectrum of aquatic systems, from lakes, through coastal marine environments to the open oceans. We are specialized in the study of sediments, where organic material is decomposed by microbes, releasing nutrients for further cycling in the environment. ABRU forms part of the Marine Ecosystems Research Group (MERG) within the Ecosystems and Environment Research Program. The unit is led by Assistant Professor (Academy Research Fellow) Tom Jilbert. Former members include Academy of Finland Research Fellows Susanna Hietanen and Karoliina Koho.