Description: Oceans cover 〉70% of the earth and encompass variable habitats concerning salinity, temperature, pressure, light availability. The deep sea (〉1000 m water depth) constitutes more than 60% of the ocean´s biosphere and harbors an unparalleled biodiversity. It constitutes an extreme habitat due to high pressure, darkness and often low nutrient and oxygen concentrations. In order to ensure their survival, microorganisms thriving in such environments have to develop unique metabolic adaptations, thus represent an interesting resource for the discovery of new molecules. However, due to access difficulties to deep-sea habitats and the lack of suitable and affordable sampling techniques, deep-sea microorganisms have remained untapped for their potential in marine biodiscovery. In this study, we obtained deep-sea sediment samples from Arctic Ocean (-2432 m), sampled by an ROV during RV Polarstern expedition 108. Isolation of microorganisms has been performed using two specific media for bacteria and fungi, respectively. Isolates were identified by amplification of the 16S rRNA gene (bacteria) and ITS1-2 region (fungi) followed by Sanger sequencing. In total, 70 bacterial isolates were identified covering four phyla (52 Firmicutes, 1 Actinobacteria, 11 Proteobacteria and 6 Bacteroidetes) and seven fungal strains from two different phyla (6 Ascomycota and 1 Basidiomycota). Selected isolates were cultivated in two different media, followed by solvent (EtOAc) extraction and bioactivity screenings against a panel of clinically relevant microbial pathogens and six cancer cell lines. At 100 µg/mL concentration, three bacterial extracts showed antitumor activity (〉70%), whereas 17 exhibited activity (〉65%) against methicillin-resistant Staphylococcus aureus (MRSA). Notably, only one fungus showed a cultivation medium dependent-high antifungal activity (〉90%), highlighting the impact of culture media on the production of bioactive secondary metabolites.

Description: The 77th cruise of the RV MARIA S. MERIAN contributed to various large national and international research and infrastructure projects (FRAM, ARCHES, INTAROS, ICOS, SIOS) as well as to the research programme PACES-II (Polar Regions and Coasts in the changing Earth System) of the Alfred-Wegener-Institute Helmholtz-Center for Polar and Marine Research (AWI). Investigations within Work Package 4 (Arctic sea ice and its interaction with ocean and ecosystems) of the PACES-II programme, aim at assessing and quantifying ecosystem changes from surface waters to the deep ocean in response to the retreating sea ice, and at exploring the most important (feedback) processes determining temporal and spatial variability. Contributions to the PACES-II Work Package 6 (Large scale variability and change in polar benthic biota and ecosystem functions) include the identification of spatial patterns and temporal trends in relevant benthic community functions, and the development of a comprehensive science community reference collection of observational data. Work carried out within WPs 4 and 6 will support the time-series studies at the LTER (Long-Term Ecological Research) observatory HAUSGARTEN (Fig. 1.1), where we document Global Change induced environmental variations on a polar deep-water ecosystem. This work is carried out in close co-operation between the HGF-MPG Joint Research Group on Deep-Sea Ecology and Technology and the PEBCAO Group (Phytoplankton Ecology and Biogeochemistry in the Changing Arctic Ocean) at AWI as well as the working group Microbial Geochemistry at the GEOMAR and the HGF Young Investigators Group SEAPUMP (Seasonal and regional food web interactions with the biological pump).

Description: The Long-Term Ecological Research (LTER) site HAUSGARTEN located in the eastern Fram Strait (79°N, 4°E) was established in 1999. Since then, year-round measurements of physical properties of the surface ocean and water column were carried out as well as biogeochemical and biological measurements of carbon fluxes to the seafloor. During a warm period in the years 2005-2007, a shift in the phytoplankton community and a decrease in phytodetritus export took place. In this study we further investigated how the dynamics of the sea ice cover and biological pump affected benthic bacterial community composition and activity. Bacterial community diversity was determined by Illumina tag sequencing. The changes in food supply caused by warming were reflected in shifts of bacterial types at the seafloor, resulting in interannual dynamics of the bacterial community structure. Our results indicate an immediate response of the benthic community to changes in surface ocean conditions, indicating that surface ocean dynamics induced by climate change are directly reflected at the seabed.

Description: Measuring temperature and salinity profiles in the world's oceans is crucial to understanding ocean dynamics and its influence on the heat budget, the water cycle, the marine environment and on our climate. Since 1983 the German research vessel and icebreaker Polarstern has been the platform of numerous CTD (conductivity, temperature, depth instrument) deployments in the Arctic and the Antarctic. We report on a unique data collection spanning 33 years of polar CTD data. In total 131 data sets (1 data set per cruise leg) containing data from 10 063 CTD casts are now freely available at doi:10.1594/PANGAEA.860066. During this long period five CTD types with different characteristics and accuracies have been used. Therefore the instruments and processing procedures (sensor calibration, data validation, etc.) are described in detail. This compilation is special not only with regard to the quantity but also the quality of the data – the latter indicated for each data set using defined quality codes. The complete data collection includes a number of repeated sections for which the quality code can be used to investigate and evaluate long-term changes. Beginning with 2010, the salinity measurements presented here are of the highest quality possible in this field owing to the introduction of the OPTIMARE Precision Salinometer.

Description: The ambition of INRAROS Initial Requirement Mapping was to define the high-level requirements of an integrated Arctic Observing System (iAOS) based on identification of the major societal drivers of a sustained observing system in the Arctic region, driven by issues affecting the entire area and expressed through international agreements (i.e. climate, environment, biodiversity, sustaining ecosystem services, improving the livelihoods of indigenous and local communities, support to maritime safety, etc.). The work was based on knowledge collected from literature studies, projects, programmes and workshops, and cover an evaluation of feasibility, readiness, and impact to provide guidance on future network design. It was decided to focus on the individual thematic areas - meteorology, terrestrial, cryosphere, sea ice and ocean – separately with the purpose of capturing the special requirements, phenomena and essential variables to observe within each of them. It very well known that these thematic areas are closely interconnected and have different levels of maturity in scientific understanding of the phenomena, definitions of essential variables and observing capacity. It is therefore a big challenge to INTAROS to use the collected information to design an integrated multipurpose and multiplatform observations system to optimises efforts and costs. Observations serve several purposes: •Process studies to gain fundamental understanding of phenomena, processes and interrelationships, which is fundamental for development of reliable forecasting models •Establish long timeseries of Essential variables at key locations to monitor variability and changes in the system •To assimilate into as well as to validate models The detailed analysis of phenomena and observation requirements for the entire region given in this report reveals the following conclusions: •The Arctic is a region very sensitive to environmental changes. There is a very close interrelation and delicate balance between the five thematic areas (atmosphere, terrestrial, cryosphere, sea ice and ocean) especially in relation to solar energy retainment and radiation budget and hydrological cycle. This has a great impact on physical, chemical and biological processes in the area. •Due to the hostile environment, there is a great lack of basic observations in the Arctic that can support scientific understanding of key processes. Most of the existing data are collected via time limited research project. This lack of process knowledge is reflected in big errors in forecasting models – operational as well as climate. •It is therefore crucial to establish a sustained Integrated Arctic Observing System that in the short timeframe can increase fundamental scientific understanding of the complex and sensitive Arctic environment and in a longer timeframe can secure a robust basis for decision making to the benefit of the people living in the Arctic, the environment, the broader international society, and commercial activities. •It is foreseen that a future Arctic observation system will rely heavily on satellite observations supplemented more traditional in-situ platforms. Especially the ocean will use several other platforms such as ships, profiling floats, gliders, moorings, AUV’s etc. to monitor the interior of the Arctic Ocean. •In all countries around the Arctic, there are community based observing systems that represent a strong potential for further development. Existing activities shall form the natural basis for a future more intensive and integrated sustainable Arctic Observing System.