EMODnet is the European Marine Observation Data network, check the EMODnet Central Portal. Deltares has been participating from the pilot phase until phase 3. Merely in EMODnet Chemistry, Biology and since phase 3 also in EMODnet Bathymetry. Other projects where Deltares is involved like EMODnet Ingestion and SeaDataCloud are also related to EMODnet. (For Internal use only: check LOIS for relevant information on these projects (documentation, project leaders, etc).)
A substantial effort has been made in creating advanced services for EMODnet Chemistry. For this project Deltares has set up a database with over 180.000.000 records which are dynamically derived using WPS services. You can find the source code at the repository of OpenEarth Tools (wps).
EMODnet is intended to advertise all data in the European Marine Domain as Open Data. It can however be quite a challenge to find and use the data as intended. Find more here for a complete example of a use case where EMODnet metadata search facilities and OGC services are used to work out the use case.
More information can be retrieve via Giorgio Santinelli, Willem Stolte, Martlin Verlaan and Gerrit Hendriksen