The biggest problem in the aquatic environment is the complexity and heterogeneity of resources as regards of their location, related themes, formats, languages and target public. Also the ongoing process of keeping information up to date, for example the appearance of new species, has to considered in order to provide the most updated information. The aquatic environment also considers aspects such as different habitats and the different species living in them, environmental themes (pollution, climate change, and so on), educational, legal and awareness aspects. The Infotech Unit at TECNALIA led the definition and development of the semantic layer of the system which enables smart and unified access to complex and heterogeneous information, spread in scientific centres throughout Europe in such a way that a visitor to AquaRing will find the resource that best fits their needs, these being considered to be language requirements, visitor type (child, teacher, adult, scientist, journalist, etc.) and the themes in which they are or might be interested. The project was led by the Aquarium of Genoa (Italy) and those taking part were the Natural Science Museum in Brussels (Belgium), the Nausicaá National Sea Centre (France), the Rotterdam Zoo (Netherlands), the Lithuanian Sea Museum (Lithuania) and Softeco Sismat Spa, an Italian IT company.. Information of public interest is provided free of charge by the web portal, www.aquaringweb.eu while certain, highly scientific content is provided on payment, although with a free preview. It is possible to carry out semantic searches on research currently under way, facilitating access to and interchange of this information. The potential users of this web portal include scientific and educational bodies, adults in general, children, media professional and teachers. The content offered is adapted to the type of user visiting us, to their language as well as to the mode of access. There is dedicated content especially for children to bring them to the wonderful world of water and a more visual environment for accessing the content. Also, writers and media professionals – printed press, radio and television – can find abundant material, both audiovisual and written, for documentation; as well as having access to the latest news on the aquatic environment at a worldwide level. The Web is currently a space prepared for interchanging information designed for human consumption. The Semantic Web initiative, launched by W3C*, means an extension of the current Web and in which information will come in a more structured manner, so such information can be processed automatically for machines. To this end, the aim of Semantic Web is to convert information into knowledge and enable the search for such information to be more efficient and intelligent.