There are increasing reports of problems with jellyfish blooms in coastal areas, heralding a need for improved understanding of the causes of these blooms and their role in marine environment. Jellyfish are currently poorly represented in biogeochemical models compared to other plankton groups. In this seminar Rebecca Wright, a Newton Fellow from the University of East Anglia presents her work on taking the first steps in adding jellyfish to a global biogeochemical model, and using it for case study on the Benguela Current System, investigating the influence of environmental fluctuations and over-fishing on jellyfish populations.