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.

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.

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

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.

This is data set held in two csv files, one DATA file contains the data and an accompanying NOTES file that provides additional detail on abbreviations. It contains processed acoustic backscatter (NASC) data that is coupled with environmental data. Acoustic backscatter data is from 13 acoustic transects spanning the Scotia Sea and major Southern Ocean fronts, obtained during cruises JR161, JR177, JR200, JR15002, JR15004 and JR16003 (2006-2017). Data were collected using a Simrad EK60 echo sounder at 38 kHz. The EK60 was run continuously between Stanley (Falkland Islands) and Signy (South Orkney Islands), Stanley and South Georgia. Environmental data includes: sea surface temperature, bathymetry, geopotential height, geostrophic current speeds, sea ice concentration, sea ice zone, time of day (day/night), sea temperature at 200m, distance to coast, net primary productivity, and hours of daylight. Environmental data are compiled from external data sources. Funding was provided by the NERC grants NE/L002434/1 and bas010017.

This dataset contains the mean position of the Southern Antarctic Circumpolar Current front (SACCF) in the Scotia Sea, southwest Atlantic sector of the Southern Ocean. The location of the front was determined from analysis of the geopotential anomaly field calculated from quality-controlled potential temperature and salinity data from the World Ocean Database 1998 (Levitus et al., 1998) supplemented by an additional hydrographic profile obtained from the Scripps Institute of Oceanography, as detailed by Thorpe (2001) and Thorpe et al. (2002). The geopotential anomaly data were gridded at a horizontal resolution of one quarter degree and spanned the period 1911-1990. The front position was generated as part of a studentship awarded to SE Thorpe, funded by the Natural Environment Research Council with CASE support from the British Antarctic Survey. The studentship was supervised by KJ Heywood, MA Brandon and DP Stevens.

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 JR177) 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 summer from December 2007 - February 2008. Dedicated acoustic transects were also run at a number of stations within these transects. The EK60 was calibrated during JR177 (10-11th February 2008). More information about the calibration can be found in the Cruise Report for JR177: https://www.bodc.ac.uk/data/information_and_inventories/cruise_inventory/report/jr177.pdf JR177 was the second 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 JR177 EK60 processed data is now available at https://doi.org/10.5285/cfc33544-e1df-4202-9d4b-c99e7f8a51d4.

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.

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.