The Laboratory of Isotope Biogeochemistry is a scientific technical facility of BayCEER. It provides as a service for all BayCEER members abundance analyses of stable isotopes of the elements carbon, nitrogen, oxygen and hydrogen, develops advanced analytical techniques for the abundance analysis of stable isotopes, provides advice in experimental design and practical experimentation with stable isotopes at natural abundance level and as tracers and performs own research projects. Here I report on ongoing own research projects of the BayCEER - Laboratory of Isotope Biogeochemistry. These projects cover the following topics: