KRILLBASE is a data rescue and compilation project which aims to improve the availability of information on two of the Southern Ocean''s most important zooplankton taxa: Antarctic krill (Euphausia superba) and salps (Family Salpidae). In 2016, the project released a database of information from 15,194 scientific net hauls, collected between 1926 and 2016 by scientists from ten countries. These data, on the density of Antarctic krill and salps, provide a resource for analysing the distribution and abundance of these taxa throughout the Southern Ocean, to support ecological and biogeochemical research as well as fisheries management and conservation. The data are available as a downloadable csv files and via a seachable web interface. Each row of the main data table represents either a net haul or a composite of several net hauls. The columns describe searchable and filterable sampling and environmental information as well as the krill and salp density. The krill data are presented as both the observed density (NUMBER_OF_KRILL_UNDER_1M2, no.m-2) and the density standardised to a single, relatively efficient sampling method (STANDARDISED_KRILL_UNDER_1M2, no.m-2). The salp data are presented as observed density for all species combined, where an individual can be either a solitary oozoid or a member of an aggregate chain (NUMBER_OF_SALPS_UNDER_1M2, no.m-2). 12,758 of the net hauls in the database include krill data, 9,726 include salp data. 7,295 of the net hauls include both krill and salp data. For hauls where data for either salps or krill were not available the relevant field is blank. The RECORD_TYPE column distinguishes between four types of record and we emphasise that every analysis of the data should first screen on this field to avoid using the same data twice. Most records are labelled "haul", and these result from a single net sampling the water column at a specific station. Others, labelled "stratified pooled haul", are the combined result of several (typically three) stratified hauls (labelled "stratified haul") sampling different parts of the water column. A small number of records, labelled "survey mean" represent the arithmetic mean densities from multiple stations as this was the only recoverable information from the relevant surveys, which were mainly conducted in the 1980s. The dataset is fully described in the following publication which should be cited in published analyses of these data: Atkinson A, Hill SL, Pakhomov E, Siegel V, Anadon R, Chiba S, Daly KL, Downie R, Fielding S, Fretwell P, Gerrish L, Hosie GW, Jessopp MJ, Kawaguchi S, Krafft BA, Loeb V, Nishikawa J, Peat HJ, Reiss CS, Ross RM, Langdon B Quetin, Schmidt K, Steinberg DK, Subramaniam RC, Tarling GA, Ward P (2017) KRILLBASE: a circumpolar database of Antarctic krill and salp numerical densities, 1926-2016. Earth Syst. Sci. Data, 9: 193-210 (doi:10.5194/essd-9-193-2017)

Quantification of interactive effects of ocean warming and ocean acidification based on near-future climate change projections on morphometrics and oocyte size of benthic invertebrates (the bivalves Astarte crenata and Bathyarca glacialis) from the Western Barents Sea. Supported by The Changing Arctic Ocean Seafloor (ChAOS) - how changing sea ice conditions impact biological communities, biogeochemical processes and ecosystems project (NE/N015894/1 and NE/P006426/1, 2017-2021), Natural Environment Research Council (NERC) in the UK.

Quantification of morphological and reproductive traits in Astarte crenata and Ctenodiscus crispatus (oocyte size/gonad index), used in the analyses by Reed et al. 2021 (Ecology and Evolution) from the Western Barents Sea during summer 2017 across a North - South Transect intersecting the polar front.

Images of histological sections of oocytes to quantify oocyte size frequency distributions in Astarte crenata and Ctenodiscus crispatus used in the analyses by Reed et al. 2021 (Ecology and Evolution) from the Western Barents Sea during summer 2017 across a North - South transect intersecting the polar front. Supported by The Changing Arctic Ocean Seafloor (ChAOS) - how changing sea ice conditions impact biological communities, biogeochemical processes and ecosystems project (NE/N015894/1 and NE/P006426/1, 2017-2021), Natural Environment Research Council (NERC) in the UK.

This dataset contains data from a study of pteropod shell dissolution on individuals exposed to CO2-enriched seawater. The data include the amount of dissolution as well as the physical and chemical parameters on which carbonate chemistry parameters were calculated.

Images of histological sections of oocytes to quantify the interactive effects of ocean warming and ocean acidification based on near-future climate change projections on oocyte size frequency distributions of benthic invertebrates (the bivalves Astarte crenata and Bathyarca glacialis) from the Western Barents Sea. Supported by The Changing Arctic Ocean Seafloor (ChAOS) - how changing sea ice conditions impact biological communities, biogeochemical processes and ecosystems project (NE/N015894/1 and NE/P006426/1, 2017-2021), Natural Environment Research Council (NERC) in the UK.

Results of sediment trap analysis conducted by British Antarctic Survey, University of Edinburgh and University of Bristol. Abundances and biovolume of intact phytoplankton and microzooplankton cells observed in sediment trap samples are presented. Data from two sediment traps deployed in the Scotia Sea, Southern Ocean, are presented (shallow=400 m, and deep = 2000 m). 4 samples were analysed from each, two in January/February 2018, and two in December 2018. Each sediment trap sample was split into multiple fractions to facilitate this and other analyses. Data facilitate the understanding of the magnitude and drivers of particulate fluxes in the Scotia Sea, Southern Ocean. Work funded by NC-ALI funding to the British Antarctic Survey Ecosystems programme.

Mesozooplankton was collected with a vertically hauled Nansen 70V net in the Gerlache Strait and vicinity of Anvers Island. The net was deployed to a maximum depth of 50 m through hand-hauling. Specimens were preserved in 4% buffered formalin. Analysis was carried out through light microscopy of the entire sample, and specimens identified to the lowest possible taxonomic level including the identification of developmental stages. Sampling was carried out as part of the REQUEST2021 T.A.S.K. (The Antarctica Scout Krill) project. The Nansen net was provided by the British Antarctic Survey as in-kind support. Sample analysis was carried out by Dr. Peter Ward, an e-fellow at BAS. REQUEST2021 was an official expedition of Kent Scouts (a county of the UK Scout Association), with further support from charitable donations.

Acoustic backscatter data were collected on board the RRS James Clark Ross (cruise JR179) as part of the BIOFLAME-BIOPEARL programme. Data were collected using a Simrad EK60 echo sounder. Data were collected throughout the cruise which ran through the Drake Passage, Bellingshausen Sea and Amundsen Sea in the Southern Ocean, from February to April 2008. 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 JR179 EK60 processed data is now available at https://doi.org/10.5285/ecc51062-1338-445e-bd3c-2e63487d1953.

The Biological Investigations of Marine Antarctic Systems and Stocks (BIOMASS) Data Set has been created as part of the BIOMASS Programme directed towards deeper understanding of the ecology of the Southern Ocean, with emphasis on krill (Euphausia superba). Data were collected during 34 cruises through a collaboration by 12 countries during three field experiments. These were: the First International BIOMASS Experiment (FIBEX) from November 1980 to April 1981, the Second International BIOMASS Experiment (SIBEX), Part 1 from October 1983 to May 1984 and Part 2 from November 1984 to April 1985. Data were collected on krill distribution from acoustic surveys and krill population structure from net-hauls. Supporting data from ichthyoplankton net-hauls, oceanographic stations (temperature, salinity, nutrients and chlorophyll-a) and observations of sea-birds at sea were also collected. The BIOMASS Data Set is composed of 43 data files, extracted from the BIOMASS Oracle relational database created by the BIOMASS Data Centre that collated and standardised the data. The validation and correction of the data were carried out during data analysis workshops by the BIOMASS Programme scientists who collected the data. The majority of the BIOMASS data have been utilized during BIOMASS workshops. However, some have not been used and must be regarded as unvalidated. The documentation accompanying the BIOMASS data set lists the known problems and validation status of the data. Funding: The BIOMASS Data Set has been generated by the BIOMASS Data Centre funded by the British Antarctic Survey. Main sponsors of the BIOMASS Programme were the Scientific Committee on Antarctic Research (SCAR) and the Scientific Committee on Oceanic Research (SCOR) in collaboration with the International Association for Biological Oceanography and the Advisory Committee on Marine Resources Research of the Food and Agriculture Organization of the UN.