Benthic communities of the Filchner Region (Weddell Sea, Antarctica)

Due to extreme pack ice, the Filchner Region in the southern Weddell Sea is one of the least studied regions on the planet. Here, we provide a detailed description of the benthic communities of this high-Antarctic ecosystem, and assess the relationship between environmental factors and benthic distribution patterns. Fieldwork was performed in the austral summers of 2013-14 and 2015-16 during the R/V ‘Polarstern’ cruises PS82 and PS96. Using a combination of multibox corer (MBC) and seabed image data from 37 stations (water depths 243-1217 m), we differentiated 6 station groups. While 1 of these groups was comprised of a single station, the other 5 groups represented distinct benthic communities. Three of these correspond to the previously described Eastern Shelf, Southern Shelf, and Southern Trench communities. However, we found distribution shifts and MBC abundance and biomass reductions when comparing our results with earlier studies. The other 2 groups have novel characteristics and are presented here as an Ice/Ice Shelf Water-related community and a Continental slope community. Water depth in combination with 2 or 3 other environmental variables (out of 7 available) explained <30% of the benthic distribution and composition. We found a tighter relationship between water mass circulation and spatial distribution of the communities; we suggest using water-mass-related characteristics (e.g. productivity regimes, water currents) to better explain benthic spatial distribution patterns

Spatial distribution and habitat preferences of demersal fish assemblages in the southeastern Weddell Sea (Southern Ocean)

Our knowledge on distribution, habitats and behavior of Southern Ocean fishes living at water depths beyond scuba-diving limits is still sparse, as it is difficult to obtain quantitative data on these aspects of their biology. Here, we report the results of an analysis of seabed images to investigate species composition, behavior, spatial distribution and preferred habitats of demersal fish assemblages in the southern Weddell Sea. Our study was based on a total of 2736 high-resolution images, covering a total seabed area of 11,317 m2, which were taken at 13 stations at water depths between 200 and 750 m. Fish were found in 380 images. A total of 379 notothenioid specimens were recorded, representing four families (Nototheniidae, Artedidraconidae, Bathydraconidae, Channichthyidae), 17 genera and 25 species. Nototheniidae was the most speciose fam- ily, including benthic species (Trematomus spp.) and the pelagic species Pleuragramma antarctica, which was occasionally recorded in dense shoals. Bathydraconids ranked second with six species, followed by artedidraconids and channichthyids, both with five species. Most abundant species were Trematomus scotti and T. lepidorhinus among nototheniids, and Dol- loidraco longedorsalis and Pagetopsis maculatus among artedidraconids and channichthyids, respectively. Both T. lepi- dorhinus and P. maculatus preferred seabed habitats characterized by biogenous debris and rich epibenthic fauna, whereas T. scotti and D. longedorsalis were frequently seen resting on fine sediments and scattered gravel. Several fish species were recorded to make use of the three-dimensional structure formed by epibenthic foundation species, like sponges, for perching or hiding inside. Nesting behavior was observed, frequently in association with dropstones, in species from various families, including Channichthyidae (Chaenodraco wilsoni and Pagetopsis macropterus) and Bathydraconidae (Cygnodraco mawsoni)

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e. a controlling message) compared to no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly-internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared to the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly-internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing: Controlled motivation was associated with more defiance and less long-term behavioral intentions to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

Master tracks in different resolutions of HEINCKE cruise HE601, Bremerhaven - Bremerhaven, 2022-06-14 - 2022-06-21

Raw data acquired by position sensors on board RV Heincke during expedition HE601 were processed to receive a validated master track which can be used as reference of further expedition data. During HE601 the inertial navigation system IXSEA PHINS III and the GPS receivers Trimble Marine SPS461 and SAAB R5 SUPREME NAV were used as navigation sensors. Data were downloaded from DAVIS SHIP data base (https://dship.awi.de) with a resolution of 1 sec. Processed data are provided as a master track with 1 sec resolution derived from the position sensors' data selected by priority and a generalized track with a reduced set of the most significant positions of the master track

Bodentiergemeinschaften im Weddell Meer : Vergangenheit, Gegenwart und Zukunft

The present thesis tackles different aspects of the past, present and future of high Antarctic benthic communities of the Weddell Sea. It first compares methodological approaches to sample benthos, showing the complementarity of two quantitative techniques. Then reviews knowledge on bentho-pelagic coupling on Antarctic shelves, showing that bentho-pelagic coupling differs considerably based on local characteristics. This methodological and conceptual knowledge is uses to study the benthic communities in the hard to access Filchner Region (southern Weddell Sea), describing two "novel" communities, and shows the influence of environmental drivers over benthic distribution. The final topic is the temporal dynamics of benthos. For this, a long-term study which considers a unique 26-year time series of benthic data from the southeastern Weddell Sea is used. Here, benthic communities appear severely affected by a decrease of productivity, and increase of scouring potential, especially after the year 2000

Benthic fauna declined on a whitening Antarctic continental shelf

Ice retreat in West Antarctica and Antarctic Peninsula has led to important changes in seafloor communities and gains in benthic blue carbon. In most of the Antarctic, however, sea ice increased between the 1970s and 2014, but its effects on the benthos remain largely unexplored. Here, we provide a 1988–2014 record of macro- and megafauna from the north-eastern Weddell Sea shelf, where benthic biomass decreased by two thirds and composition shifted from suspension feeders to deposit feeders. Concomitant increases in sea-ice cover suggest a reduced flux of primary production to the benthos. As benthic communities are major repositories for Antarctic biodiversity and play an important role in biogeochemical cycling, the observed changes have far-reaching consequences for the Antarctic ecosystem and its feedback to the climate system. The findings underscore the importance of long-term ecological monitoring in a region vulnerable to warming and ice-shelf collaps