Colleagues Sign up for the next Skills and Training Session here: https://zoom.us/meeting/register/WmeDiyJhRPiYbWQTRqV_yA 10 December 2025 Stable isotopes - biogeochemistry<https://zoom.us/meeting/register/WmeDiyJhRPiYbWQTRqV_yA> Savannah Worne, Loughborough University Stable isotope are powerful tools for tracing the sources and cycling of elements in environmental systems. Stable isotopes ratios can vary due to physical, chemical and biological processes, making them valuable tracers in biogeochemistry. By analysing these variations, we can identify nutrient sources, track biogeochemical transformations, and understand ecosystem interactions. In this seminar, I will introduce the principles of stable isotope biogeochemistry and its applications in aquatic systems. I will then present a case study from my fellowship research at Rutland Water Nature Reserve, where I have undertaken a multi-stable isotope investigation to investigate the influence of sewage-derived nutrients and waste water management strategies on algal blooms. This approach has allowed me to disentangle nutrient sources, assess the extent of sewage inputs, and explore how these inputs interact with lake biogeochemistry to drive bloom dynamics. Kevin Murphy Executive Director, Mineralogical Society of the UK and Ireland kevin@minersoc.org<mailto:kevin@minersoc.org>