The datasets refer to the dating of three basaltic samples collected from Bruce Bank and Jane Bank in the southern Scotia Sea. The samples were dredged from depths between 850 -1900 m from steep scrap slopes at two locations (DR.225: 59.927 degrees S, 39.154 degrees W; DR.84: 62.468 degrees S, 039.785 degrees W). The files include full analytical datasets for 40Ar/39Ar analysis of whole rock and plagioclase mineral separates performed at the Open University, UK in June 2022. This project was funded by NERC NC-ALI funding to Geology & Geophysics.

Zooplankton faecal pellet abundance, volume and flux were determined from samples collected at three stations in the Scotia Sea, Southern Ocean during cruise JR304. Samples were collected at six depths within the 0 - 400 m epi- to upper mesopelagic using Niskin bottles attached to a CTD unit and were preserved in a formalin-based solution. Fluorescence data were collected during the same deployments. Sampling was performed by C. Liszka and G. Tarling on board RRS James Clark Ross. Sample analysis was performed by C. Liszka at British Antarctic Survey in Cambridge.

This dataset contains atmospheric methane and carbon dioxide concentration data in the Southern Ocean and South Atlantic Ocean, and dissolved methane concentration data from surface and water column seawater samples in the Scotia Sea, Weddell Sea, and South Georgia shelf taken onboard RRS Discovery during DY158 from December 2022 and January 2023. Atmospheric methane and carbon dioxide concentration was measured using a Los Gatos Ultraportable Greenhouse Gas Analyser (UGGA) G2311-f. The concentrations are 2 hour averaged and have been filtered based on wind direction to data corresponding to wind coming from behind the ship to remove sources of pollution from the ship stack. Surface seawater samples were taken either using the uncontaminated seawater system or from the surface sample from a CTD (Conductivity-Depth-Temperature) cast. Water column seawater samples were taken from a CTD with Niskin bottle rosette-casts at various depths spanning from the sea surface to the seafloor. The dissolved methane concentration in each seawater sample is measured using gas chromatography. Funding source: This work was supported by the Natural Environment Research Council and the ARIES Doctoral Training Partnership (grant no. NE/S007334/1). The fieldwork was supported by the Collaborative Antarctic Science Scheme (CASS).

We present a new bathymetric compilation of the greater South Georgia region, here defined by a bounding box of ~900km (45W to 19W) by ~580km (63S to 50S) and covering an area of 530,000 km2. The region includes the South Georgia shelf, the Shag Rock shelf (to the west of South Georgia), the surrounding continental slopes and adjacent deep sea. This bathymetry grid was compiled from a variety of different data sources including multibeam swath bathymetry collected from scientific cruises undertaken by British Antarctic Survey (BAS), Alfred Wegener Institute (AWI) and the Institute of Geophysics, University of Texas. The grid has been constructed using a layered hierarchy dependent on accuracy of each dataset. The data is available as a 100m resolution GeoTIFF, ESRI ascii grid or KMZ file of elevation data along with a shapefile indicating the spatial coverage of all the contributing datasets. This work was supported by the National Environmental Research Council (grant number NE/L002531/1). For further information regarding the creation of this dataset please refer to doi:10.1038/srep33163.

We present two new gridded bathymetric compilations of the Orkney Passage, Scotia Sea here defined by the following bounding boxes: 39.1 to 39.6 W, 60.55 to 60.7 S and 41.7 to 42.6 W, 60.45 to 60.8 S. These bathymetry grids were compiled from a variety of multibeam swath bathymetry data acquired during 12 different cruises (see lineage). The data is available as grids of 50 m resolution in a GMT-compatible (2-D) NetCDF format using geographic coordinates on the WGS84 datum. This grid was compiled in support of the ongoing monitoring efforts in and around Orkney Passage as part of the Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA) programme and preceding BAS NC projects, and the Dynamics of the Orkney Passage Outflow (DynOPO) project. Funding was provided by the NERC grants NE/K012843/1 and NE/N018095/1 as well as national capability

Mesopelagic fish were sampled in the Scotia Sea using a 25 m2 opening and closing rectangular midwater trawl during five research cruises on RRS John Biscoe and RRS James Clark Ross. Nets sampled discrete layers, from the surface to 1000 m during austral spring, summer and autumn. The data include 17726 individual fish records from 66 taxa, the most abundant of which were myctophids of the genera Electrona, Gymnoscopelus, Krefftichthys and Protomyctophum and bathylagids (Bathylagus sp.). Length (standard length, total length or pre-anal fin length) was measured for the majority of specimens (16837), with sex and weight data also collected for many. The work was conducted as part of the BAS Ecosystems Programmes funded by the UK Natural Environment Research Council.

Among all possible interaction types, trophic interactions are easily observable and essential in terms of energy transfer, and thus binary networks have arisen as the most straightforward method to describe complex ecological communities. These food-web models also inform on the ecosystem dynamics and function, and the patterns arising from food web topology can be indicators for ecosystem stability. We present a comprehensive pelagic network for the Scotia Sea underpinned by surveys and dietary studies conducted in the Scotia Sea in the last century. Selection of the trophic links followed a protocol based on taxonomy and geographic location, and was further refined based on the consumer and resource depth ranges and their body size ratios. The resulting network consists on 228 nodes and 10880 links which represent the main trophic paths in the Scotia Sea ecosystem and can serve as a basis for ecosystem modelling in the Scotia Sea or comparison with other ecosystems. Funding was provided by NERC Highlight Topic grant NE/N005937/1 and NERC Fellowship NE/L011840/1.

This dataset comprises chlorophyll-a and phaeopigment-a concentrations (mg l-1) obtained from seawater samples collected during cruise DY098 on the RRS Discovery during the period 2019-01-02 to 2019-02-10. The cruise was part of the POETS-WCB and SCOOBIES time-series with an additional survey undertaken around the South Sandwich Islands (SSI). The data contained within this dataset were predominantly collected during the SSI component of the cruise. Samples were collected at up to 6 depths across the top 400 m (approx. 5 m, 50 m, 100 m, 200 m, 400 m and the chlorophyll maximum). Samples were collected and filtered on board and analysed at the British Antarctic Survey laboratory. This work was funded through NERC National Capability Science funding (NC-SS) for the Polar Ocean Ecosystem Time Series (POETS) and FCO grant NEB1686.

Acoustic backscatter data were collected on board the RRS James Clark Ross (cruise JR161) as part of the Discovery 2010 programme. Data were collected using a Simrad EK60 echo sounder at 38, 120 and 200 kHz. The EK60 was run continuously from Stanley (Falkland Islands) to Signy (South Orkney Islands), then to South Georgia across the Scotia Sea in the austral spring (October - December) of 2006. Dedicated acoustic transects were also run at eight stations within these transects. The EK60 was calibrated prior to data collection on a previous cruise (JR159 on 13-14th October 2006). More information about the calibration can be found in the Cruise Report for JR159: https://www.bodc.ac.uk/data/information_and_inventories/cruise_inventory/report/jr152_jr159.pdf JR161 was the first of three cruises which comprise the field studies of the British Antarctic Survey''s (BAS) core science Discovery 2010 programme, funded by the Natural Environment Research Council. *******PLEASE BE ADVISED TO USE PROCESSED DATA******* The JR161 EK60 processed data is now available at https://doi.org/10.5285/c831d5e4-8d03-4aea-a6c6-6db101f36d8d.

Acoustic backscatter data were collected on board the RRS James Clark Ross (cruise JR200) as part of the Discovery 2010 programme. Data were collected using a Simrad EK60 echo sounder. This cruise ran two transects (Stanley to Signy and Signy to South Georgia) across the Scotia Sea in the austral autumn (March - April) of 2009. Within these transects, there were a series of stations at which dedicated acoustic transects were run, although the EK60 was run continuously throughout the cruise. JR200 was the third of three cruises which comprise the field studies of the Discovery 2010 programme. The programme was designed to analyse interactions in the Southern Ocean ecosystem. The raw data files (Simrad .raw format) are held by the Polar Data Centre (PDC) at the British Antarctic Survey (BAS). *******PLEASE BE ADVISED TO USE PROCESSED DATA******* The JR200 EK60 processed data is now available at https://doi.org/10.5285/7b86ed5f-0520-4dec-9d1e-f76be05b98c9.