Description: Sea ice is the major constraint on human activities in the Southern Ocean. Depending on a vessel's ice class, human mobility may be restricted or even prevented altogether by sea-ice conditions. This may imply limited access to research or monitoring stations, preferred fishing grounds or attractive tourist sites. Here, we introduce a statistical model that evaluates the sea-ice cover with two measures: 1) accessibility (i.e. the probability that a given area is navigable by vessels at a given time) and 2) repeated accessibility (i.e. the probability that a given area is navigable by vessels at a given time and again at least once within a defined timespan). We use daily sea-ice concentration data from 2002 to 2020 to demonstrate this tool and its functioning regarding the spatiotemporal variability of sea-ice cover in the wider Weddell Sea region. These findings reflect known characteristics of sea-ice distribution and dynamics in the Weddell Sea, confirming the functionality of our simple tool for determining repeated accessibility of certain areas. Such a tool may facilitate the planning of research and monitoring activities in the Southern Ocean, as well as in Arctic seas.

Description: Bivalve sclerochronological records with annually resolved growth bands are applicable proxies in reconstructing features of the hydro-climate system. Here we evaluate the relationship between growth indices of A. islandica, previously collected at approximately 82 m depth in the North Atlantic, and seasonal subsurface temperature at various depths for the 1900–2005 period. Correlations with sea surface temperature at the collection site are not significant during winter and weak for the remaining seasons. The strongest in-phase correlations persist for summer and autumn below 56 m water depth, whereas weaker correlations are lagged by one or two years. We also observe similarities with distant water bodies in the North Atlantic sector, and a corresponding large-scale oceanographic pattern that increases significantly with water depth along the trajectory of the North Atlantic Current. We suggest that by investigating the relationship with the temperature signal at various depths locally and at large-scale increases the reliability and application of bivalve shells as marine archives.

Description: The Southern Ocean may contribute a considerable amount to the proposed global network of marine protected areas (MPAs) that should cover about 10 % of the world's oceans in 2020. In the Antarctic, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is responsible for this task, and currently Germany leads a corresponding scientific evaluation of the wider Weddell Sea region. Compared to other marine regions within the Southern Ocean, the Weddell Sea is exceptionally well investigated. A tremendous amount of data and information has been produced over the last 4 decades. Here, we give a systematic overview of all data sources collected in the context of the Weddell Sea MPA planning process. The compilation of data sources is comprised of data produced by scientists and institutions from more than 20 countries that were either available within our institutes, downloaded via data portals or transcribed from the literature. It is the first compilation for this area that includes abiotic data, such as bathymetry and sea ice, and ecological data from zooplankton, zoobenthos, fish, birds and marine mammals. All data layer products based on this huge compilation of environmental and ecological data are available from the data publisher PANGAEA via the six persistent identifiers at https://doi.org/10.1594/PANGAEA.899595 (Pehlke and Teschke, 2019), https://doi.org/10.1594/PANGAEA.899667 (Teschke et al., 2019a), https://doi.org/10.1594/PANGAEA.899645 (Teschke et al., 2019b), https://doi.org/10.1594/PANGAEA.899591 (Teschke et al., 2019c), https://doi.org/10.1594/PANGAEA.899520 (Pehlke et al., 2019a) and https://doi.org/10.1594/PANGAEA.899619 (Pehlke et al., 2019b). This compilation of data sources including the final data layer products will serve future research and monitoring well beyond the current MPA development process.

Description: Data on marine biota exist in many formats and sources, such as published literature, data repositories, and unpublished material. Due to this heterogeneity, information is difficult to find, access and combine, severely impeding its reuse for further scientific analysis and its long-term availability for future generations. To address this challenge, we present CRITTERBASE, a publicly accessible data warehouse and interactive portal that currently hosts quality-controlled and taxonomically standardized presence/absence, abundance, and biomass data for 18,644 samples and 3,664 benthic taxa (2,824 of which at species level). These samples were collected by grabs, underwater imaging or trawls in Arctic, North Sea and Antarctic regions between the years 1800 and 2014. Data were collated from literature, unpublished data, own research and online repositories. All metadata and links to primary sources are included. We envision CRITTERBASE becoming a valuable and continuously expanding tool for a wide range of usages, such as studies of spatio-temporal biodiversity patterns, impacts and risks of climate change or the evidence-based design of marine protection policies.

Description: During the Continental Shelf Multidisciplinary Flux Study (COSMUS) expedition from February to March 2021 aboard RV Polarstern (expedition ID: PS124) (Hellmer & Holtappels, 2021), a large spawning aggregation of notothenioid icefish (Neopagetopsis ionah, Nybelin 1947) was discovered in the southern Weddell Sea. The CCAMLR community was informed of this discovery by Germany in COMM CIRC 22/10 and SC CIRC 22/08 earlier this year (17 January 2022). Purser et al. (2022) report on the spawning aggregation in Current Biology. Here we provide detailed information on the active fish nest aggregation and on additional icefish nesting sites observed in the Filchner Trough area (Knust & Schröder, 2014; Schröder, 2016; Riginella et al., 2021; Purser et al., 2022; Purser et al., in review).

Description: In times of rapidly increasing multiple anthropogenic impacts on polar marine ecosystems and biodiversity, understanding, sustainable-use management and protection of these biotas is a matter of great concern. Research on marine biotas and their interactions with each other and the environment is fundamental in that regard, but available data are still diverse and scattered, as they exist in many formats and sources, such as published literature, data repositories, and unpublished material. Due to this heterogeneity, information is difficult to find, access and combine, severely impeding its reuse for further scientific analysis and its long-term availability for future generations. Scientists, decision makers, and the public require a versatile tool to compile, synthesize and manage biodiversity data in a transparent, efficient and comprehensible way and with high-level quality assurance. To address this challenge, we developed, implemented and utilize CRITTERBASE (https://critterbase.awi.de), a publicly accessible data warehouse and interactive portal that complies with the FAIR principles (Findability, Accessibility, Interoperability and Reusability of data). Its purpose is to complement long-term data storage repositories by providing powerful but easy-to-use data ingest, retrieval and exploration tools, thus facilitating the analysis of biodiversity data across multiple spatial and temporal scales and in wider contexts. Currently, it hosts quality-controlled and taxonomically standardized presence/absence, abundance, and biomass data from Arctic, North Sea and Antarctic regions, collated from the literature, unpublished data, own research and online repositories (with all metadata and links to primary sources included), for 3,173 polar benthic taxa (2,444 of which at species level) from 12,209 samples collected with grabs, underwater imaging or trawls between 1800 and 2014. CRITTERBASE is currently holding benthic biodiversity data only but because of its comprehensive and flexible data model it is suited to include information about further biotas and habitats. Therefore, we envision it becoming a valuable and continuously expanding tool for a wide range of usages, such as studies of spatio-temporal biodiversity patterns, impacts and risks of climate change or the evidence-based design of marine protection policies.

Description: The Collector's App is a platform-independent (macOS, Linux and Windows) software written in Python. The Collector's App allows biological data to be quality-checked and stored in CRITTERBASE, which is a science-driven PostgreSQL data warehouse for marine biota. For further data processing and statistical analyses or modelling purposes, the respective data can be queried directly via SQL from your CRITTERBASE data warehouse.

Description: The following downloadable R scripts for calculating the repeated accessibility are available here: 1. "Download of daily sea ice raster" - The R script automatically downloads all GeoTiffs from IUP, University of Bremen, and saves them in the directory of your choice. 2. "Existing and missing data" - The R script uses the downloaded GeoTiffs to create a table showing for which days satellite images are available and for which days they are not. 3. "Information of GeoTiffs" - The R script extracts important metadata of the downloaded GeoTiffs such as geographical projection, spatial extent and maximum value. A metadata table is created. 4. "Repeated accessibility" - The R script performs the repeated accessibility calculation based on a selectable threshold of sea ice concentration.