The International Society for Environmental Biogeochemistry (ISEB) Symposium – to be held at the Helmholtz Centre Potsdam German Research Centre for Geosciences (GFZ) – will bring together scientists from all over the world to discuss recent developments and discoveries from all aspects of Environmental Biogeochemistry, including but not limited to microbiology, chemistry, soil science, geoscience, limnology, ecology, marine and atmospheric sciences both from fundamental and applied perspectives. Exploration of the deep terrestrial and marine biosphere will be a major topic of the conference; so far, 20% of the abstracts are deep biosphere related. The meeting will be in a single session format, so all participants have the chance to attend all oral presentations. Daily poster sessions provide sufficient time for discussions among the participants. Abstract submission deadline extended to June 30, 2019.