The soil food webs in this collection represent a total of 32 belowground communities studied by Neutel et al. (2007), from two natural successions in sandy dune soils: one on the Waddensea Island of Schiermonnikoog in the north of the Netherlands and the other at Hulshorsterzand, on the Veluwe, in the central Netherlands. The study sites, which constitute the two gradients, represent four consecutive stages in chronosequences of early primary vegetation succession, increasing in aboveground and below-ground productivity. The Jacobians of the 32 food webs (two series, four stages with four replicates per stage) were calculated by Neutel et al. (2007) from observed average biomass data of the respective systems, and inferring steady-state biomass flow data using a procedure described by Hunt et al. (1987). The Jacobians represent the interaction strengths of the species in the two food webs, evaluated at equilibrium.

Macrozooplankton and nekton were collected with a Rectangular Midwater Trawl 25 (RMT25) at locations within the Benguela Current region in May and June 2018. The work was carried out as part of the NERC Large Grant, COMICS (Controls on Mesopelagic Interior Carbon) on board the RRS Discovery (cruise DY090). Depth-discrete samples were collected across four time stations (BS1, BN1-3) between 0-750 m at intervals of 750-500m, 500-250m, 250-125m and 125-10 m. At each time station, two RMT25 hauls were deployed in the hours of darkness and two in daylight, with 16 deployments being undertaken overall. The RMT25 was operated via a downwire net monitor and was equipped with a flow meter, and temperature and salinity sensors. Nets in the deep strata (750-500m and 500-250m) were sampled for approximately 40 mins. and nets in the shallow strata (250-125m, 125-10m) for approximately 20mins. Catches were immediately sorted on board and identified to the lowest taxonomic level feasible. All fishes and subsamples of the other parts of the catch were retained (frozen), principally for subsequent biochemical and physiological analyses. In total, 1917 fish were caught and preserved (not including Cyclothone spp.). Catches were dominated by the myctophids and various other mesopelagic fish species. The water column below 250m was dominated by Bathylagus spp. and genus Melamphidae spp. The most numerous fish overall were the Cyclothone spp. which occurred in large numbers below 500m. In deeper depth intervals (250m-750m), the macrozooplankton component of the RMT25 net catches was mostly dominated by Decapoda and hydromedusae of the genus Atolla spp.. Salps, smaller hydromedusa species and small euphausiids Euphausia hanseni and Nematocelis megalops dominated the shallower depths (10-250m).

Macrozooplankton and nekton were collected with a Rectangular Midwater Trawl 25 (RMT25) over several visits to the sustained observation location P3 (52.70 S, 40.26 W) in the northern Scotia Sea during November and December 2017. The work was carried out as part of the NERC Large Grant, COMICS (Controls on Mesopelagic Interior Carbon) on board the RRS Discovery (cruise DY086). The RMT25 net hauls sampled between 10 and 500 m depth, with the water column divided into 2 depth intervals (10-250 m and 250-500 m). A total of 6 hauls were obtained during 3 separate visits to station P3, each visit comprising a pair of hauls, of which one was carried out in nominal daytime and the other in nominal nighttime. Catches were immediately sorted on board and identified to the lowest taxonomic level feasible. Subsamples of the catches were retained, principally for subsequent biochemical and physiological analyses. In total, 777 fish were caught, belonging to at least 23 species, with catches dominated by the myctophids Krefftichthys anderssoni, Gymnoscopelus braueri, Electrona antarctica and Protomyctophum tenesoni. The water column below 250m was dominated by Bathylagus spp. Temperate myctophid species, such as Protomyctophum parallelum and Protomyctophum andreyeshevi were also caught in small numbers. With regards macrozooplankton, the 250m-500m depth interval was dominated by the jellyfish, Atolla and Periphylla. The tunicate Salpa thompsoni and the euphausiids Euphausia triacantha and Thysanoessa spp. were also relatively abundant. Jellyfish still dominated catches in shallower waters (250m-10m), closely followed by euphausiids and Salpa thompsoni and chaetognaths. Themisto gaudichaudii and Parandania boecki were the most numerous amphipod species caught. Decapods were only caught in the deeper depth interval, both day and night.

In 2012 RRS James Clark Ross investigated the marine benthic biodiversity of the southern Weddell Sea (JR275), in 2016 the marine benthic biodiversity of the South Orkney Islands (JR15005) and in 2018 the marine benthic biodiversity of the Prince Gustav Channel area. In 2019 RV Polarstern investigated the marine benthic biodiversity of the eastern Antarctic Peninsula (PS119). During all expeditions macrobenthic isopod fauna (Peracarida, Crustacea) was collected by a total of 37 epibenthic sledge (EBS) and assessed for species richness and abundance. In total 27099 isopod specimens assigned to 228 morphospecies and 78 genera were identified. To set the isopod dataset into a wider context of species diversity, published isopod species richness data from a further EBS collected stations during the ANDEEP I-III expeditions (ANT XIX/2-3, ANT XXII-3) in the Weddell Sea (Brandt et al. 2007) were added. This dataset provides data for 1) Isopoda EBS station locations and environmental data, 2) EBS Isopoda abundance data JR275, JR15005, JR17003a and PS118, 3) Isopoda species absence/presence data JR275, JR15005, JR17003a and PS118, 4) Isopoda species absence/presence data ANDEEP Weddell Sea only. Funding for KL, HJG, and the RRS James Clark Ross expeditions was provided by NERC for NC Science (JR275, JR15005) and for NERC urgency grant NE/R012296/1 ''Benthic biodiversity under Antarctic ice-shelves - baseline assessment of the seabed exposed by the 2017 calving of the Larsen-C Ice Shelf'' (JR17003a). Ship time for EBS work during PS118 was provided to Linse et al. via a co-user grant from Leitstelle Deutsche Forschungsschiffe (AWI-PS118_7). Funding for DD was provided by the Deutsche Forschungsgemeinschaft grant Br1121/51-1. Financial support for the ANDEEP I-III expeditions was provided by the Deutsche Forschungsgemeinschaft grant Br1121/22/1-3.

Mesozooplankton were collected with a motion-compensated Bongo net (61 cm mouth diameter, 100 and 200 micrometre meshes) and a mini- Bongo net (18 cm mouth diameter, 50 micrometre mesh nets). Both nets fished to a maximum depth of 400 m but sometimes shallower. Specimens were categorised to the lowest possible taxonomic level, which in some cases encompassed developmental stages but in other cases was limited to higher order taxa. Each taxa was enumerated to determine abundance in units of individuals m-2. The dataset allows examination of the distribution and abundance of these species within the Atlantic sector of the Southern Ocean over a number of years and covering much of the productive season from spring to autumn. The data for the North Atlantic and Arctic covers one season only (summer) and is limited to providing a spatial perspective on the distribution and abundance of mesozooplankton.

In 2018 RRS James Clark Ross investigated the marine benthic biodiversity of the Prince Gustav Channel area and the macrobenthic molluscan fauna collected by epibenthic sledge (EBS) has been assessed for species richness, abundance and assemblage composition as well as for functional traits. In total 20,307 mollusc specimens assigned to 50 morphospecies and 4 classes (Solenogastres, Bivalvia, Gastropoda and Scaphopoda) were identified. Assemblage analyses across the Prince Gustav Channel area did not show apparent pattern or separation across depth, taxon or station. To set the bivalve dataset into a wider context, unpublished bivalve species richness and abundance data from EBS collected stations in the area influenced by the Weddell Gyre were added. This doi dataset provides data for 1) PGC EBS locations, 2) PGC EBS molluscan abundances, 3) PGC molluscan functional traits, 4) Weddell Gyre EBS stations (300 - 2000 m depth), 5) Weddell Gyre EBS bivalve standardised 1000 m trawl length abundances (300 - 2000 m depth). Funding was provided by NERC urgency grant NE/R012296/1 ''Benthic biodiversity under Antarctic ice-shelves - baseline assessment of the seabed exposed by the 2017 calving of the Larsen-C Ice Shelf''.

This dataset contains quality-controlled georeferenced occurrence records of three Arctic Calanus species (Calanus finmarchicus, C. glacialis and C. hyperboreus), downloaded from the Ocean Biodiversity Information System (OBIS) and the Global Biodiversity Information Facility (GBIF) databases. Records span about 150 years of sampling (1870-2017), are located between 30 and 90 degrees north, and are distributed between the surface and 5000m deep. Physical (bathymetry) and environmental (temperature and sea-ice concentration) parameters are matched to each occurrence record. An html file provides the annotated source code for the data processing, analyses and figures produced for the publication: Freer JJ and Tarling GA (2023) Assessing key influences on the distribution and life-history of Arctic and boreal Calanus: Are online databases up to the challenge? Front. Mar. Sci. 10:908112. This work was funded by DIAPOD (NE/P006213/1) and CHASE (NE/R012687/1) projects as part of the Changing Arctic Ocean Programme, with the former funded by the UKRI Natural Environment Research Council (NERC) and the latter, jointly by NERC and the German Federal Ministry of Education and Research (BMBF). Further support was provided by BIOPOLE National Capability Multicentre Round 2 funding from the Natural Environment Research Council (NE/W004933/1).

Benthic Macrofaunal abundance and biomass data collected during a series of ship-board sampling campaigns in the Barents Sea. As part of the NERC funded Changing Arctic Ocean programme, in July of 2017, 2018 and 2019, the RSS James Clark Ross followed a North-South transect at 30 degrees Longitude. In 2017 six stations were sampled (B3, B13, B14, B15, B16, B17); in 2018 seven stations were sampled (B3, B13, B14, Xs, B15, B16, B17); and in 2019 five stations were sampled (B3, B13, B14, B15, B16). Macrofaunal samples were collected using a USNL corer (surface area 0.1m<sup>2</sup>). On recovery all faunal samples were fixed and preserved with 10% buffered formaldehyde solution. The faunal samples were transported to Plymouth Marine Laboratory where the fauna were extracted, identified to species level where possible using the most up to date literature available, and biomassed (blotted wet weight) to species level. A reference collection has been created containing an example of each taxon to ensure maximum quality control was maintained by the three analysts that conducted the species identification and for subsequent cruise data generated. Funded by the NERC Changing Arctic Ocean Seafloor (ChAOS).

Cetacean sightings in South Georgia and South Sandwich Islands waters, made by a team of four professional marine mammal observers during the British Antarctic Survey CCAMLR synoptic krill survey on the RRS Discovery (DY098), January and February 2019. The latitude and longitude of each sighting, the identified species, bearing and distance from the vessel, and estimated group size are provided. These data have been used by BAS to estimate (i) humpback whale and (ii) baleen whale abundance in South Georgia and South Sandwich Islands waters in 2019. Funding was provided by the Foreign, Commonwealth and Development Office, as part of the Overseas Territories Blue Belt programme, as well as the South Georgia Heritage Trust, Friends of South Georgia Island and Darwin PLUS award DPLUS057.

The Antarctic food webs represent two entire above-belowground communities from Signy Island Reference Sites on Signy Island, one of the South Orkney Islands in the Maritime Antarctic. The two communities are a dry moss community (Antarctic dry tundra) and a wet moss community (Antarctic wet tundra). These two communities were the focus of intensive biological study by personnel from the British Antarctic Survey over the course of a decade in the 1970''s, of which the results were finally compiled into a meta-analysis by Davis (1981). The Jacobians of the dry and wet tundra were calculated by Neutel and Thorne (2014) using the empirical biomass and flow data of the respective systems from Davis'' analysis. The Jacobians represent the interaction strengths of the species in the two food webs, evaluated at equilibrium.