Résumé
The long-term observatories of the OZCAR Critical Zone Research Infrastructure (https://www.ozcar-ri.org/ ) were initially set up to answer scientific questions of local interest to society. To answer these questions, a series of variables documenting meteorological conditions, hydro-geochemistry of surface water or aquifers, land surface fluxes and soils, as well as land use and practices are collected, sometimes over several decades. In the context of open science, these data are shared according to the FAIR (Findable, Accessible, Interoperable, Reusable) principles. However, a recurring question is the usefulness of making this data available and the use made of it by local stakeholders or citizens. To answer this question, observatory managers were asked to provide information on - The measured variables from their observatory used by local actors, - The stakeholders who use their data- The type of data used (raw data or data already transformed/digested by scientists) - The type of interactions they have with stakeholders.The results of the consultation show that the data is primarily used in universities or as part of initial training. Long-term involvement in the study-areas has also led to the establishment of long-lasting relationships with stakeholders (e.g. local authorities, hydropower companies, river basins management authorities, water agencies, Regional Natural Parks, state agencies (e.g. forest managers), associations, farmers and the public. Often, but not always, these stakeholders make direct use of the data produced by the observatories included in OZCAR RI. Qualified data from several monitored sites are used to manage the drinking water supply of several towns or municipalities, flood warning systems (in this case in near-real time or in a a posteriori analysis of problematic episodes), quantify water resources (quantity, quality), understand soil quality, or monitor wetland restoration. Nevertheless, in the face of increasingly strong and frequent pressures and disturbances, local stakeholders are increasingly questioning critical zone observatories to obtain data, trends and projections on the impact of climate change or land use. This information will help them to draw up regulatory documents and make decisions on the future habitability of their areas. Scientists are also called upon to provide scientific mediation and make the results of their research accessible to non-specialists. In addition to data, decision-makers, elected representatives and the public expect scientists to provide them with indicators that can be used more directly than raw data. In order to provide satisfactory responses to these new needs, it is necessary to co-construct the various actions, which requires time and a strong investment by scientists and stakeholders. As a result, new missions and new jobs are emerging, making observatories meeting places for local stakeholders and scientists. Observatories are becoming places, named Living Labs, where knowledge and research questions can be co-constructed, where citizens can be involved in metrology (participatory science), in order to better respond to the challenges of the Earth's habitability in the various areas.