OSU-Réunion is an Observatory of the Sciences of the Universe based in Réunion and one of France’s 25 OSUs. It coordinates research and observation services to improve understanding of Earth and the wider natural environment, bringing together work across atmospheric science, geology, hydrology, marine science and forest ecology. Initially focused on tropical atmospheric observations, its activities have expanded to cover a broad range of environmental systems and global change.

The organization supports a network of research stations: OPAR monitors tropical climate, including greenhouse gases, aerosols and clouds; OZC-R/STAFOR studies tropical forest ecosystems and biodiversity; ERORUN observes erosion and watershed hydrology; and OCTOPUS focuses on coastal geomorphology, marine ecology and ocean physics. OSU-Réunion also provides research infrastructure, technical and administrative support, data access and scientific services. Its GEOSUR catalog shares datasets produced by its research community, while its research federation encourages interdisciplinary projects. The observatory contributes to science education through support for master’s programs, seminars, internships and training opportunities, and hosts collaborations with researchers in Réunion and internationally.