MEDUSA is positioned as an ‘‘intermediate complexity’’ model of the plankton ecosystem founded on the oceanic nitrogen cycle. While simplified, it is designed to include sufficient complexity to address major feedbacks between ocean biogeochemical cycles and anthropogenic drivers such as climate change (CC) and ocean acidification (OA). MEDUSA is developed and operated within the framework of the Nucleus for European Modelling of the Ocean (NEMO) physical model.


MEDUSA is used routinely in open ocean modelling activities within NOC, and output from it feeds into a wide range of collaborative research projects and activities. MEDUSA is also the marine biogeochemistry component of the UK’s first community Earth System Model, UKESM1, and a participant in the Coupled Model Intercomparison Project, Phase 6 (CMIP6). As part of this, output from MEDUSA was used in Assessment Report 6 (AR6) produced by the Intergovernmental Panel on Climate Change, including (with BORIS) in key evidence for benthic ecosystem changes. MEDUSA is currently being developed for use in as part of UKESM2, and its output will feed into CMIP7.

In associated work at NOC, MEDUSA’s organic material flux to the seafloor is used to drive the Benthic Organisms Resolved In Size (BORIS) model of seafloor macrofauna communities.