Revealing the secrets of Norway's seafloor – geological mapping within the MAREANO programme and in coastal areas

Results from geological mapping within the MAREANO (Marine Areal Database for Norwegian Coasts and Sea Areas) programme and mapping projects in the coastal zone reveal a rich and diverse seafloor in Norwegian territories. The geomorphology and sediment distribution patterns reflect a complex geological history, as well as various modern-day hydrodynamic processes. By early 2019, MAREANO has mapped more than 200 000 km 2 ( c. 10%) of Norwegian offshore areas, spanning environmental gradients from shallow water to more than 3000 m depth, with ocean currents in places exceeding 1 m s −1 and water temperatures below −1°C. Inshore, along the 100 000 km-long Norwegian coastline, the Geological Survey of Norway (NGU) has conducted a series of seabed mapping projects in collaboration with local communities, industry and other stakeholders, resulting in detailed seabed and thematic maps of seabed properties covering c. 10 000 km 2 (11% of the areas). Bathymetric and geological maps produced by MAREANO and coastal mapping projects provide the foundation for benthic habitat mapping when combined with biological and oceanographic data. Results from the mapping conducted over the past decade have significantly increased our understanding of Norway's seabed and contributed to the knowledge base for sustainable management. Here we summarize the main results of these mapping efforts.