Beschreibung: The present compilation is the first attempt to generate a comprehensive list of all macrozoobenthic species recorded at least once in the German regions of the North Sea and Baltic Sea including non-indigenous species and freshwater species which occurred in brackish waters (estuaries, bays, fjords etc.). Based on the data of several research institutes and consultancies, the macrozoobenthic species inventory comprises a total of 1.866 species belonging to 16 phyla including 193 threatened species. The most common groups were: malacostracan crustaceans (21%), Polychaeta (19%), and Gastropoda (12%). Even though the two major marine regions are separated by only 50 km of land, the composition of the respective communities was different. The two seas shared only 36.6% of the recorded species which should have profound and far-reaching consequences for conservation purposes. Considering all macroinvertebrates listed 96 species, or the equivalent of 5.2%, were introduced mainly during the last two centuries. Both seas are heavily affected by human activities and are sensitive to climate change displayed by effects on the faunal compositions. The present checklist is an important step to document these changes scientifically and may act as a base for political and management decisions.

Beschreibung: Permanent sea-ice cover and low primary productivity in the mostly ice-covered Central Arctic ocean basins result in significantly lower biomass and density of macrobenthos in the abyssal plains compared to the continental slopes. However, little is known on bathymetric and regional effects on the macrobenthos diversity. This study synthesizes new and available macrobenthos data to provide a baseline for future studies of the effects of Arctic change on macrofauna community composition in the Arctic basins. Samples collected during three expeditions (in 1993, 2012 and 2015) at 37 stations on the slope of the Barents and Laptev Seas and in the abyssal of the Nansen and Amundsen Basins in the depth range from 38 m to 4381 m were used for a quantitative analysis of species composition, abundance and biomass. Benthic communities clustered in five depth ranges across the slope and basin. A parabolic pattern of species diversity change with depth was found, with the diversity maximum for macrofauna at the shelf edge at depths of 100–300 m. This deviates from the typical species richness peak at mid-slope depths of 1500–3000 m in temperate oceans. Due to the limited availability of standardized benthos data, it remains difficult to assess if and how the significant sea-ice loss observed in the past decade has affected benthic community composition. The polychaete Ymerana pteropoda and the bryozoan Nolella sp. were found for the first time in the deep Nansen and Amundsen Basins.

Beschreibung: Little is known about the distribution and dynamics of macrobenthic communities of the deep Arctic Ocean. The few previous studies report low standing stocks and confirm a gradient with declining biomass from the slopes down to the basins, as commonly reported for deep-sea benthos. In this study, we investigated regional differences of faunal abundance and biomass, and made for the first time ever estimates of deep Arctic community production by using a multi-parameter artificial neural network model. The underlying data set combines data from recent field studies with published and unpublished data from the past 20 years, to analyse the influence of water depth, geographical latitude and sea-ice concentration on Arctic benthic communities.We were able to confirm the previously described negative relationship of macrofauna standing stock with water depth in the Arctic deep sea, while also detecting substantial regional differences. Furthermore, abundance, biomass and production decreased significantly with increasing sea-ice extent (towards higher latitudes) down to values B200 ind m�2,B65 mg C m�2 and B73 mg C m�2 y�1, respectively. In contrast, stations under the seasonal ice zone regime showed much higher standing stock and production (up to 2500 mg C m�2 y�1), even at depths down to 3700 m. We conclude that particle flux is the key factor structuring benthic communities in the deep Arctic Ocean as it explains both the low values in the ice-covered Arctic basins and the higher values in the seasonal ice zone.

Beschreibung: Numerous ecosystem goods and services, such as marine biodiversity, long-term carbon storage and natural resources (e.g. for fish, birds, mammals and finally humans), are intimately linked to the benthic system. Maintenance of the benthic system at a healthy ecological status is thus of particular interest. The mandatory monitoring concept of offshore wind farm effects on the marine environment (StUK) prescribes extensive investigations on soft-bottom benthos and fouling assemblages of the wind turbine foundations. StUK and studies beyond StUK in the test field alpha ventus (North Sea, German Bight) were carried out to evaluate the German monitoring concept. Our investigations show a massive colonization of turbine foundations by fouling organisms and an aggregation of megafauna around constructions, both resulting in a local increase in biomass and species richness of the benthos, but no direct turbine effects on the soft-bottom benthos at the scale investigated. Temporal variations of sediment conditions and benthic communities were similar inside and outside the wind farm area. During the alpha ventus case-study, limits of benthic ecological studies according to StUK became evident and recommendations were elaborated for future improvements. Beyond our field studies, an aggregated database of StUK data from approved wind farms and data from research projects serves as the base for large-scale benthic ecosystem analysis. Current efforts are being made to quantitatively estimate benthic species distributions on a transnational scale, a prerequisite for cross-border spatial planning. Further, we strive to estimate species or group specific “natural corridors of variation” to discriminate anthropogenic effects from natural background variability. Finally, functionally sensible areas and important geographic sites that are of public concern regarding ecosystem services and goods are to be identified. This data will be used to provide evaluation criteria for identifying sensible areas in the context of licensing procedures of offshore wind farms and marine spatial planning. Study outcomes (e.g. in terms of maps) are made public via the internet (GeoSeaPortal) in order to provide stakeholders, e.g. authorities and scientific institutions, with scientific advice.