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.

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.

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.

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.

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.

High-resolution X-ray computed tomography images of two deep-sea bamboo corals (Acanella arbuscula, Johnson, 1862; Keratoisis sp., Wright, 1869) collected from Baffin Bay and Davis Strait during a research expedition on board the CCGS Amundsen in July-August 2021. Corals were imaged using Micro-Focused X-Ray Computed Tomography at the Micro-Vis X-ray Imaging Centre (Southampton, UK) to non-destructively investigate their skeletal architecture, calcification strategies and growth patterns. Supported by a National Environmental Research Council Funded (INSPIRE) PhD [grant number NE/S007210/1, 2019-2027, awarded to T.J.W] and the National Research Facility for Lab X-ray CT (NXCT) [EPSRC grant number EP/T02593X/1].

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.

Transcriptomic analyses were undertaken on both in situ collected and experimentally warmed blue mussels (Mytilus edulis) from Greenland. M. edulis were collected from the Godthabsfjorden near Nuuk, Greenland (64.45555, -51.14416) at the following locations and dates: Inner fjord (64.45941, -50.31030) on 11/06/2018; outer fjord (64.19666, -51.69) on 13/06/2018, and sub-tidal (64.19666, -51.69) on 13/06/2018 (outer fjord at 20-40cm below the lowest low water mark). The in situ collected inner and outer fjord intertidal animals with outer fjord subtidal animals used as controls were collected at 27 degree Celsius, 19 degree Celsius and 3 degree Celsius, respectively. Some of the outer fjord subtidal M. edulis were experimentally warmed to 22 degree Celsius and 32 degree Celsius for one hour to mimic high aerial exposure temperatures in the inner and outer fjord intertidal, respectively. RNA-Seq was performed on 5 animals for each treatment, with all subsequent bioinformatics analyses performed by Novogene, China. This work was supported by the Carlsberg Foundation, the Independent Research Fund Denmark (Danmarks Frie Forskningsfond) (DFF-International Postdoc; case no. 7027-00060B), a Marie Sklodowska-Curie Individual Fellowship (IF) under contract number 797387 and Aage V. Jensens Fond (Aage V. Jensens Foundation) and NERC-UKRI core funding to the British Antarctic Survey.

Sediment cores were taken using a box corer. The sediment was subsampled using a 20 x 20 x 12 cm and incubated for 12 days. At the end of incubation, the macrofauna retained (500 um sieved) from each aquarium were fixed in 10% phosphate buffered formalin (4% formaldehyde) and stored in sealed plastic buckets for a minimum of three months. Prior to identification samples were rinsed and preserved in 70% industrial methylated spirit (IMS). Using a stereo microscope, all the animals were picked out of the residue, stored in vials containing 70% IMS, and identified to the lowest possible taxon with abundance and biomass per taxon noted. Biomass was obtained using blotted wet weight (+/- 0.0001g). The individual numbers of each taxa were counted to give abundance data. This was determined by the presence of a head in cases where specimens had been damaged. Any badly damaged specimens or parts of specimens where no head was present were separated into major group debris (annelid, mollusc and crustacea) pots and their presence noted as YES/NO for abundance). All molluscs were weighed inclusive of shells, tube dwelling polychaetes were weighed without tubes, and sediment was removed from the body cavity of specimens of Ctenodiscus crispatus prior to weighing. Samples were collected on cruises JR16006 and JR17007. Funding was provided 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), part of the NERC funded Changing Arctic Ocean programme.