Marine citizen science must be made more open and FAIR’ to facilitate cooperation and DTOs

In a study of 1,267 marine citizen-science initiatives, a team of researchers including some of the EU-funded Iliad project, concluded that insufficient openness of marine citizen science data and insufficient adherence to the FAIR principles (that data should be Findable, Accessible, Interoperable and Reusable) is limiting the application and overall usefulness of marine citizen science data.

“Marine citizen science initiatives around the globe are on the increase, many are sustained over long periods of time, and they are of increasing relevance for marine science; yet the uptake of marine citizen science data is hampered by their ‘closedness’ and poor data management practices—they are far from being fully open and following the FAIR principles—as well as by difficulties with their appropriate categorisation, affecting all future uses (both intended and unplanned),” the researchers said.

The study, titled “Past and present marine citizen science around the globe: A cumulative inventory of initiatives and data produced” and published on 3 February 2025 in the Ambio journal of environment and society, was carried out and authored by Uta Wehn of the IHE Delft Institute for Water Education, together with Ane Bilbao Erezkano, Luke Somerwill, Torsten Linders, Joan Maso, Stephen Parkinson of Earthwatch Europe, Christina Semasingha and Sasha Woods. 

“More effort needs to be made in making the data from marine citizen science initiatives FAIR,” the team argued, detailing what particularly should be done to do so, and stressing that the necessary steps should be made at the beginning of a citizen science initiative. 

Compliance with all four FAIR principles could only be demonstrated for only 2 of the 1267 marine citizen science initiatives surveyed. A mere 10 initiatives could be considered to be sufficiently interoperable, and a similar number were sufficiently accessible. Only 73 initiatives included reference to a license allowing for reusability of the data. Just over 200 initiatives of the 1267 surveyed provided a mechanism allowing for easy access to their data.

“The step from knowing a marine citizen science initiative exists to accessing its data is still considerable,” the team commented.

As for the fundamental “openness” of the data produced by marine citizen science initiatives, the team found that only 18% of the 1267 initiatives surveyed claim to provide full open access to the raw data collected and 23% give partial access (such as in a report, summary or factsheet), while fully 59% of the initiatives surveyed provide no access to their raw data at all. As a result, the FAIR analysis discussed above could only even be applied to the 41% of the initiatives found to be sufficiently open with their data in the first place, and at most 43% could be considered open or partially open. 

“This number is significantly lower than the average for citizen science initiatives at large, with a recent study suggesting that 57% of [general citizen science] initiatives make their data open to the public in some form. In specific fields of citizen science, adherence to open data principles has been found to be even higher, with 69% of biodiversity citizen initiatives making data accessible,” the researchers said.

“This situation is not exceptional in citizen science, and, moreover, common for marine in situ data: they are traditionally collected by many different entities, resulting in data scattered throughout unconnected databases and repositories, often using incompatible formats, rendering the sharing of the information and data aggregation particularly challenging,” the team added.

The lack of reusability, on the other hand, “limits the usefulness and the scope of the data gathered to the marine citizen science initiatives that capture them, making the initiatives [themselves] the only actors capable of generating information and knowledge from the data.”

Initiatives’ shortcomings in terms of openness and FAIR principles ultimately translate into difficulties when integrating data from similar initiatives and in Digital Twins of the Ocean (DTOs), the team said, as they are likely nonetheless measuring concepts that are incompatible or only partially overlapping. 

“Marine citizen science initiative as a potential data source to support Digital Twins of the Ocean is a potential yet to be fully realised,” the researchers commented.

The marine citizen science metadata inventory used in the study, together with the content surveying 1267 initiatives, provides the basis for a dynamic online database (MARCSI) that can be continually enhanced by adding new initiatives, they added.