New update of harmonised seabed substrate data available

EMODnet Seabed substrate data products comprise of multiple datasets at different scales, compiled in subsequent EMODnet geology projects running since 2009. In the projects, diverse, national datasets are harmonised into a shared schema which includes not only information on seabed substrate, but also background and confidence level of the data.  

Seabed substrate data products are:

• Multiscale (1:25 000, 1:50 000, 1:100 000, 1:250 000, 1:1 000 000) 
• 1:100 000
• 1:250 000
• 1:1 000 000
• Sediment accumulation rates

Download links and information about the individual data products can be found on the Geology Portal. 

Seabed substrate harmonisation is done by reclassifying the diverse national data by using the modified Folk classification system. This EMODnet reclassification scheme includes at least five seabed substrate classes and is supported by European nature information system, EUNIS. Four substrate classes are defined on the basis of the modified Folk triangle (mud to sandy mud; sand; coarse sediment; and mixed sediment) and one additional substrate class (rock and boulders).  If the original seabed substrate dataset has enabled more detailed substrate classification, classifications with 7 and 16 substrate classes might be available.

The harmonised schema has been enhanced on the way and some of the attributes have not therefore been gathered in the first place and are missing from the older datasets at 1: 1 000 000 and 1: 250 000 scales. The data coverage varies between scales and in time it has been collated.

Basic background attributes include information on e.g. country, data holder, scale and original classification system, and seabed substrate attributes include information on e.g. reclassification, original substrate, Folk classes and additional surface features. Confidence information is based on remote sensing coverage, amount of sampling and distinctness of class boundaries.