The present project aims at coupling MITgcm with FABM to enable modular biogeochemical process representations within a state-of-the-art ocean circulation framework. The development will ensure full compatibility with existing pelagic and benthic biogeochemical models available in FABM. This coupling will expand the MER system, allowing seamless integration and intercomparison of alternative ecosystem formulations. A verification suite will be set up to confirm numerical consistency and conservation properties after coupling. The task includes running idealized and realistic test cases to validate physical–biogeochemical interactions and model stability and scalability on MER suite domains.