EMODnet Chemistry’s best practices were used to build the UNESCO global system of ocean oxygen data

Organisation

The Global Ocean Oxygen Database and ATlas (GO2DAT) is a UNESCO project hosted under the UNESCO ‘Global Ocean Oxygen Decade’ programme (GOOD). This is an endorsed programme of the UN Decade of Ocean Science for Sustainable Development (2021–2030), led by LEGOS – Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, in partnership with the University of Liège – on behalf of the Global Ocean Oxygen Network (GO2NE) of the UNESCO Intergovernmental Oceanographic Commission (IOC). GOOD aims to raise global awareness of ocean deoxygenation and provide knowledge to address and mitigate the impacts of climate change.

The project runs from April 2022 to December 2030. In 2019, GO2NE and other international experts conceptualised GO2DAT to develop a common entry point for high-quality ocean oxygen data from various observing Eulerian and Lagrangian platforms, in both coastal and open ocean areas (Grégoire et al., 2021, Front. Mar. Sc.). The objective is not to establish a new database but rather a federated system within the new IOC data fabric architecture. To this end, they emphasised the importance of adopting widely interoperable metadata formats and documented quality control (Garçon et al., 2026, Env. Res. Letters).

Challenges Faced 

Over the past 60 years, greenhouse gas emissions and nutrient loading have driven increasing deoxygenation in both coastal and open ocean areas, posing risks to marine organisms that depend on oxygen to survive. Addressing these risks and supporting sustainable management of the climate system and ocean health requires substantially increased ocean oxygen data acquisition. At present, however, data coverage remains insufficient. To overcome this, global ocean oxygen data sources must be federated, with harmonised access, discovery, and processing capabilities – an effort that requires significant coordination and expertise. 

In 2019, participants in the UNESCO initiative ‘Global Ocean Oxygen Database and ATlas (GO2DAT)’ accepted this challenge. In 2021, GO2DAT defined a roadmap outlining the theoretical basis for improving the interoperability of ocean oxygen datasets (Grégoire et al., 2021) and is currently working on its implementation. As reported by Garçon et al., (2026), this requires: (I) guidance on ocean oxygen measurements, (II) recommended practices for ocean oxygen data management, including metadata requirements, uncertainty and quality control, and (III) development of the ocean oxygen data platform, fully integrated with cross-domain infrastructures such as the Ocean Data and Information System (ODIS).

EMODnet Chemistry is a member of the GO2DAT steering committee, alongside representatives from the WOD*, WOA*, IOCCP*, GLODAP*, Argo, IAP* database, and CMEMS*, among others. Together, with a wide array of consulted experts, the community has produced an inventory of measurement guidance, a summary of current data and metadata management practices, and a framework for the ocean oxygen database and online platform. These outcomes and the proposed way forward for GO2DAT are synthesised in the paper above and provide a template for other Essential Ocean Variables (EOVs). 

* List of acronyms: CMEMS - Copernicus Marine Environment Monitoring Service; GLODAP - Global Ocean Data Analysis Project; IAP database - Institute of Atmospheric Physics database; IOCCP    International Ocean Carbon Coordination Project; WOA - World Ocean Atlas; WOD - World Ocean Database

EMODnet Services Used 

Regarding practices for metadata, data formats, and vocabularies related to ocean oxygen data, the GO2DAT metadata content specification considers the requirements of EMODnet Chemistry, the Argo programme, and the WOD. GO2DAT identifies EMODnet Chemistry as the EU-funded service that enables users to access dissolved oxygen concentration data included in its aggregated, harmonised, and validated data collections on eutrophication. GO2DAT also recognises the value of the SeaDataNet (SDN) infrastructure used by EMODnet Chemistry for its technical set-up, as well as the SDN standards for metadata and common vocabularies, which ensure consistency and interoperability. For these reasons, EMODnet Chemistry practices were used to design the GO2DAT metadata content specification and harmonised oxygen data workflows.

Regarding data quality control of oxygen observations, EMODnet and WOD are identified as the primary archives and databases of interest due to their large volumes of hosted data and their administration by the European Commission and the National Oceanic and Atmospheric Administration (NOAA), respectively.  EMODnet quality control procedures were used as a reference model, as GO2DAT notes that they are based on both objective criteria and regional expert judgement. 

The EMODnet marine best practices were used in combination with other data. GO2DAT searched for refereed and endorsed documents about dissolved oxygen metadata on Ocean Best Practices. GO2DAT then constructed a set of properties based on the requirements of Sustainable Development Goal (SDG) Indicator 14.3.1 for ocean acidification. The GO2DAT metadata content specification takes into account requirements from the Argo program, the WOD and EMODnet.

Visit the Ocean Best Practice repository, EMODnet Tools and guidelines and SeaDataNet  to access and download the EMODnet best practices used.

Impact of EMODnet
EMODnet Chemistry best practices included in the “EMODnet Chemistry Community Practices” were used to produce the paper. This represents best practice in itself and serves as an inventory of the most important best practices for building the UNESCO Global System of Ocean Oxygen Data.

EMODnet Chemistry best practices, including manuals, guides, protocols, and standard operating procedures, will contribute to achieving the UNESCO Global System goal of improving the quality, consistency, and effectiveness of data acquisition and accessibility. Using EMODnet Chemistry best practices offers many benefits, including increased collaborative opportunities, more efficient use of time, improved system operability, enhanced data comparability and interoperability, greater trust in data, streamlined regulatory approvals, and higher funding success.