Résumé
The explosion in the number of ontologies and semantic artefacts has come with the importance of developing Semantic Artefact Catalogues to support diverse research communities to harvest, share and serve these artefacts as FAIR objects. However, the lack of interoperability of these catalogues hampers cross disciplinary studies and make semantic stakeholders work quite cumbersome juggling back and forth from one tool to another. In this paper, we define Semantic Artefact Catalogues interoperability and report on three approaches studied. We present the implementation of the OntoPortal Federation, i.e., the technical and collaboration processes engaged to federate multiple OntoPortal-based catalogues. We showcase how AgroPortal, EcoPortal, EarthPortal, and BiodivPortal, have been federated and now enable federated browsing and search, facilitating seamless access to distributed semantic artefacts and ontologies across their respective disciplines: agri-food, ecology, earth sciences and biodiversity. We discuss technical challenges and governance decisions and conclude by outlining future directions toward a sustainable and community-driven OntoPortal-based semantic layer for open science data infrastructures.