Description: The MAREANO (Marine AREA database for NOrwegian coast and sea areas) mapping programme includes acquisition of multibeambathymetry and backscatter data together with a comprehensive, integrated biological and geological sampling programme. Equipment used includes underwater video, box corer, grab, epibenthic sled and beam trawl. Habitat maps are produced by combining information on landscapes, landscape elements, sediment types and biological communities. Video observations provide information about the megafauna diversity of large ([1 cm) epifauna and bottom types, whilst bottom samples describe the composition of epifauna, hyperfauna (crustaceans living in the upper part of the sediment and/or swimming just above the substratum) and infauna, and sediment composition. In this study, two biological data sets are used to study fauna response to environmental heterogeneity at two different spatial scales: (1) broad scale, megahabitat (1–10s km), based on information about megafauna taxa observed during video surveys in the Nordland/Troms area, (2) fine scale, mesohabitat (10s m-1 km), based on information about species composition documented with video records and bottom sampling gear from the bank ‘‘Tromsøflaket’’. In general, the highest diversity is found on bottoms with mixed substrates indicating that substratum heterogeneity is very important for the biodiversity at both scales. The number of taxa shows a maximum at depths between 200 and 700 m followed by a gradual decrease down to 2,200 m. At the broad scale, multibeamdata provides a variety of terrain variables that indicate environmental variation (e.g. exposure to currents, interpreted substrates). This analysis identifies six fauna groups associated to specific landscape elements. Diversity of megafauna shows a strong correlation with number of bottom types occurring along video transects. It is highest at the shelf break and decreased with depth on the slope in parallel with a decrease in habitat heterogeneity and temperature. At a fine scale, six biotopes are identified based on megafauna composition with habitat characteristics ranging from homogenous muddy bottom, biotope 1, to the most heterogeneous bottom with[20% rocks and several bottom types present in biotope 6. The macrofauna sampled is used for description of the whole benthic community, including diversity, biomass and production, related to these six biotopes. The variation in percentage cover of substrate types and in particular the cover of hard substrates demonstrate to be a good proxy for the benthic community composition (mega and macrofauna) and its diversity.

Description: Important ecosystem services and goods such as marine biodiversity, long-term carbon storage and natural food resources for higher trophic level (e.g. for fish, birds, mammals and finally humans) are inextricably linked to the benthic system. Benthic production and productivity are thus of direct relevance for the management of commercial fish stocks and other ecosystem functions that benthos provide. The identification of essential feeding habitats, i.e. highly productive areas, in the benthos are therefore of commercial interest and consecutively also for a marine ecological management. The MAREANO project (Marine AREA database for NOrwegian coasts and sea areas) studies both the seabed environment and the benthic invertebrates, hitherto covering an area of 107 000 km² in the Barents and Norwegian Seas. The dataset may form a platform of benthic knowledge for an ecosystem-based sustainable management of these offshore waters. Hence, MAREANO links the environmental parameters to the benthic ecosystem in order to map the environment and fauna off the Norwegian coast. The area studied first by MAREANO was the Tromsøflaket bank in the Barents Sea (approx. 16 km2, 150 – 200 m depth) which served as a case-study area. Multibeam echosounder data which provide a basis for terrain analysis were combined with sampling with several biological sampling gears (video, beam trawl, grab and epibenthic sled) in order to analyse and map benthic habitat distribution. Based on the combined analysis, six different benthic biotopes were characterised for Tromsøflaket. The benthic production and productivity showed significant differences between biotopes and strong correlation with environmental parameters, i.e. terrain parameters from multibeam echosounder analysis, sediment type and trawl tracks. Production differences were also found between taxonomic groups and feeding guilds between biotopes. Consecutively, the results will enable to designate highly productive and/or sensitive areas important to understand ecosystem-related functional biotope aspects of Norwegian seas in the future.