Carbonate sand deposits in Norway

The aim of the National Program for Mapping Biodiversity – Coast is to provide Norwegian managers and planners with maps of the distribution of marine habitats and key areas for species. Carbonate sand is composed of skeletal fragments from marine organisms, mostly shells, snails, barnacles, sea urchins and calcareous algae, accumulating during the past 10 000 years. Carbonate sand deposits with ongoing production and accumulation were identified through distribution modelling (using statistical methods such as GAM, BRT, Maxent) based on presence–absence data of carbonate sand deposits from grab samples (collected by the Geological Survey of Norway). Depth, wave exposure and ocean current speed were the most important predictors. Polygon areas were derived from the model according to the routine established in the Norwegian National Program for Mapping Biodiversity – Coast.