Seabed geomorphic features in a glaciated shelf of the Baltic Sea

Abstract Due to a continuous increase in human activities occurring throughout marine and coastal areas worldwide (e.g., marine traffic and construction), the lack of in-depth information on vast marine areas is problematic. However, the spatial informatics field has enabled the development of new applications based on pre-existing spatial data. This paper discusses the physical structure and complexity of the continental shelf seafloor, using geospatial modelling and GIS analysis to gain insight into the physical environment of the Baltic Sea seafloor as a basis for ecosystem management. We demonstrate the mapping of coherent features over a broad region and identify geomorphic features of the seabed by analysing and modelling bathymetric, seabed substrate, and photic depth datasets. The analysis was performed at the kilometre scale using a grid size of 200 m. In total, 18 unique seabed geomorphic features were identified from the entire Baltic Sea (including the Skagerrak). The features are similar to geomorphic seafloor structures typically occurring on glaciated continental shelves. The Baltic Sea is primarily characterized by various plains and basins, and on average, one-third of the seafloor can be regarded as a sediment accumulation area. Other seabed geomorphic features are mainly present in certain local sub regions. The archipelagos as well as the coastal areas of southern Sweden and the Bothnian Bay have a heterogeneous seafloor environment. These areas are characterized by sea valleys and holes, sea troughs, and bedrock elevations, partly due to a crystalline basement and glacial erosion. In addition, the shallow coastal areas suffer from intense wave exposure and have erosional features that differ from those in open sea areas. Effective transnational marine spatial planning requires extensive knowledge of the environmental characteristics of the region in question. Background data for marine spatial planning can be obtained through an analysis of seabed geomorphic features, which provides consistent information on the physical marine environment over a broad area.