The numerous benefits of Open Science (OS) and of the four FAIR foundational principles -Findable, Accessible, Interoperable and Reusable- are increasingly valued in academia, although what OS and FAIR entail is still largely misunderstood. In such conditions putting in practice OS and applying the FAIR principles is challenging and underrated. However, realising OS is perfectly within grasp provided that an infrastructure supporting the management of the research lifecycle is available. RoHub is precisely a Research Object (RO) management platform implementing three complementary technologies: Research Objects, Data Cubes and Artificial Intelligence-based Text Mining services. RoHub enables researchers to collaboratively manage, share and preserve their research while they are still working on it (rather than after the work is finished). In this paper, three communities from Earth Sciences, namely Geohazards, Sea Monitoring and Climate Change, demonstrate how RoHub helped them to understand each other and to work openly, and more importantly how communities of practice play an important role in facilitating reuse and interdisciplinary collaboration. These findings are illustrated with several use cases from these various communities.