Units: umol/l. Method: spatial interpolation produced with DIVA (Data-Interpolating Variational Analysis). URL: http://modb.oce.ulg.ac.be/DIVA. Comment: Every year of the time dimension corresponds to a 10-year centred average for each season : - winter season (December-February), - spring (March-May), - summer (June-August), - autumn (September-November). Diva settings: Snr=1.0, CL=0.7

EMODnet Chemistry aims to provide access to marine chemistry data sets and derived data products concerning eutrophication, ocean acidification and contaminants. The chemicals chosen reflect importance to the Marine Strategy Framework Directive (MSFD). This regional aggregated dataset contains all unrestricted EMODnet Chemistry data on contaminants (20 parameters), and covers the Arctic Ocean with 548 CDI records divided per matrices: 235 water profiles, 313 sediment profiles. Vertical profiles temporal range is from 1974-03-25 to 2015-06-15. Data were aggregated and quality controlled by ‘Institute of Marine Research - Norwegian Marine Data Centre (NMD)’ from Norway. Regional datasets concerning contaminants are automatically harvested. Parameter names in these datasets are based on P01, BODC Parameter Usage Vocabulary, which is available at: http://seadatanet.maris2.nl/bandit/browse_step.php . Each measurement value has a quality flag indicator. The resulting data collections for each Sea Basin are harmonised, and the collections are quality controlled by EMODnet Chemistry Regional Leaders using ODV Software and following a common methodology for all Sea Regions. Harmonisation means that: (1) unit conversion is carried out to express contaminant concentrations with a limited set of measurement units (according to EU directives 2013/39/UE; Comm. Dec. EU 2017/848) and (2) merging of variables described by different “local names” ,but corresponding exactly to the same concepts in BODC P01 vocabulary. The harmonised dataset can be downloaded as ODV spreadsheet (TXT file), which is composed of metadata header followed by tab separated values. This worksheet can be imported to ODV Software for visualisation (More information can be found at: https://www.seadatanet.org/Software/ODV ). The same dataset is offered also as XLSX file in a long/vertical format, in which each P01 measurement is a record line. Additionally, there are a series of columns that split P01 terms in subcomponents (measure, substance, CAS number, matrix...).This transposed format is more adapted to worksheet applications users (e.g. LibreOffice Calc). The 20 parameter names in this metadata record are based on P02, SeaDataNet Parameter Discovery Vocabulary, which is available at: http://seadatanet.maris2.nl/v_bodc_vocab_v2/vocab_relations.asp?lib=P02 . Detailed documentation will be published soon. The original datasets can be searched and downloaded from EMODnet Chemistry Download Service: https://emodnet-chemistry.maris.nl/search

Units: umol/l. Method: spatial interpolation produced with DIVA (Data-Interpolating Variational Analysis). URL: http://modb.oce.ulg.ac.be/DIVA. Comment: Every year of the time dimension corresponds to a 10-year centred average for each season : - winter season (December-February), - spring (March-May), - summer (June-August), - autumn (September-November). Diva settings: Snr=1.0, CL=0.7.

Units: umol/l. Method: spatial interpolation produced with DIVA (Data-Interpolating Variational Analysis). URL: http://modb.oce.ulg.ac.be/DIVA. Comment: Every year of the time dimension corresponds to a 10-year centred average for each season : - winter season (December-February), - spring (March-May), - summer (June-August), - autumn (September-November). Diva settings: Snr=1.0, CL=0.7.

This gridded product visualizes 1960 - 2014 water body silicate concentration (umol/l) in the North Sea domain, for each season (winter: December – February; spring: March – May; summer: June – August; autumn: September – November). It is produced as a Diva 4D analysis, version 4.6.9: a reference field of all seasonal data between 1960-2014 was used; results were logit transformed to avoid negative/underestimated values in the interpolated results; error threshold masks L1 (0.3) and L2 (0.5) are included as well as the unmasked field. Every step of the time dimension corresponds to a 10-year moving average for each season. The depth dimension allows visualizing the gridded field at various depths.

Black corals are antipatharian corals that occur from sublittoral to abyssal depths on hard, mixed and soft substrates. Under favourable conditions, some black coral species form dense stands known as black coral gardens which create habitat for a variety of associated species.

Dataset collating kelp occurrences (presences and absences) from surveys conducted across the Azores archipelago (NE Atlantic) using remotely operated vehicles, drop-down cameras, open and closed-circuit SCUBA diving, and fisheries by-catch information.

Circalittoral faunal turfs are animal-dominated shelf assemblages that are found on hard substrata between the lower limit of the infralittoral zone and the shelf edge. Benthic organisms generally form dense intricate mixes that may include tall alcyonarians, sponges, hydroids, scleractinians and gorgonians, as well as less prominent fauna such as encrusting sponges, bryozoans, ascidians, bivalves, solitary cup corals, serpulid worms and vermetid gastropods.

Rhodoliths is a general term used to designate non-geniculate coralline red algae (Rhodophyta) that live unattached (Riosmena-Rodríguez, 2017). The term is used here to encompass (i) branched free-living coralline algae devoid of an evident nucleus, but also (ii) nucleated nodules where the biogenic calcium carbonate deposit around the core represents >50%, as well as (iii) “coated grains” where the core is larger than the algal carbonate component.

Dataset contains species name, their number of specimen and wet-weight for each taxa (0,1 mg). Samples were originally preserved in formaline and later converted to ethanol. After identification samples are stored at Bergen Museum/University of Bergen.