ALBERT

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.

Description: Benthic marie systems of the Norwegian shelf belong to the most diverse cold water systems on marine shelves. At the same time these systems experience strong anthropogenic impacts and provide significant services and goods, which calls for a sustainable management based on an ecosystem approach. The MAREANO project (Marine AREA database for NOrwegian coasts and sea areas) aims at addressing the knowledge gaps on the seabed and environment as the base for a sustainable management. Therefore, large parts of the northern Norwegian shelf have been intensively studied with multibeam echosounder, providing detailed bathymetry data for terrain analysis and backscatter data, which aids sediment interpretation. The area has also been sampled by different biological gears (video, beam trawl, grab, epibenthic sled) to investigate benthic habitat distribution. Species diversity, abundance and biomass have been determined, and secondary production and productivity of macrozoobenthic organisms modeled. Here, we present results from data covering an area of 48 000 km2 of the Norwegian continental margin between the Lofoten islands and North Cape and from the Norwegian and Barents Sea. The study area stretches from banks on the shelf (80 m depth) to the deep-sea plains (2750 m), and has been samples with 101 stations during seven cruises from 2006-2009. This dataset is unique in spatial coverage as it presents for the first time large-scale macrozoobenthic production on the Norwegian continental shelf. We will present spatial distribution of the macrozoobenthic production and productivity, together with an introductory analysis of the connections between different benthic biological characteristics (taxonomic, functional groups) and sediment as well as terrain parameters for benthic landscapes that have been defined for the same area using video analyses. For the first time, the outcomes will allow to estimate large-scale benthic production and productivity and therefore to evaluate high and low productive benthic regions on the Norwegian shelf.

Description: Maps of surficial sediment distribution and benthic habitats or biotopes provide invaluable information for ocean management and are at the core of many seabed mapping initiatives, including Norway's national offshore mapping programme MAREANO (www.mareano.no). Access to high-quality multibeam echosounder data (bathymetry and backscatter) has been central to many of MAREANO's mapping activities, but in order to maximize the cost-effectiveness of future mapping and ensure timely delivery of scientific information, seabed mappers worldwide may increasingly need to look to existing bathymetry data as a basis for thematic maps. This study examines the potential of compiled single-beam bathymetry data for sediment and biotope mapping. We simulate a mapping scenario where full coverage multibeam data are not available, but where existing bathymetry datasets are supplemented by limited multibeam data to provide the basis for thematic map interpretation and modelling. Encouraging results of sediment interpretation from the compiled bathymetry dataset suggest that production of sediment grain size distribution maps is feasible at a 1:250 000 scale or coarser, depending on the quality of available data. Biotope modelling made use of full-coverage predictor variables based on (i) multibeam data, and (ii) compiled single-beam data supplemented by limited multibeam data. Using the same response variable (biotope point observations obtained from video data), the performance of the respective models could be assessed. Biotope distribution maps based on the two datasets are visually similar, and performance statistics also indicate there is little difference between the models, providing a comparable level of information for regional management purposes. However, whilst our results suggest that using compiled bathymetry data with limited multibeam is viable as a basis for regional sediment and biotope mapping, it is not a substitute. Backscatter data and the better feature resolution provided by multibeam data remain of great value for these and other purposes.