We defined the interfaces between the air/snow, snow/ice, and ice/ocean and calculated the ocean heat flux for two SIMBA recordings (SIMBA2015a and SIMBA_2015f) of repeated temperature profiles at 6h interval and 2cm vertical resolution, during N-ICE 2015 experiment floe1. The snow/ice interface is derived from the sharp contrast in the diffusivity proxy values between both media. The snow/ice interface does not change except for slush formation associated with flooding events. The air/snow interface is calculated using simultaneous information from the vertical gradient of the temperature and the standard deviation over 24, 48, and 72 h period. Snow accumulation of more than 10 centimeters happened at different time for the 2 SIMBA. The ice/ocean interface is estimated from temperature profiles alone since the winter sea-ice remains colder than the ocean. The ocean just below the ice is at or just above the freezing temperature (estimated from a near surface conductivity-temperature-depth (CTD) sensor see Koenig et al. [2016]). The method detects (1) the first sensor, downward of the snow/ice interface, with a temperature above the ocean freezing temperature and (2) the last sensor in the ice with a temperature below the mean ocean temperature by at least twice the ocean temperature standard deviation in that profile. The ice/ocean interface is then defined as half way between the last sensor in the ice and the first sensor in the ocean. Note it take 3-4 days for the deployment hole to refreeze. Then the ice thickness remains constant up to 20 February when floe1 breaks. Simba_2015f stops working and SIMBA_2015a features basal melt events corresponding to temperature changes in the ocean. The consistency of the 3 interfaces estimate is validated with the thermal diffusivity proxy and the vertical and temporal derivatives of temperature. The ocean heat flux is derived from the latent heat flux which is directly proportional to the change in time of the ice/ocean interface depth and the conductive heat flux in the lower portion of the ice estimated 6 cm above the ice/ocean interface. The ocean heat flux values for SIMBA_2015a and SIMBA2015f range from -50 to 350 W/m2, and -50 to 150 W/m2 respectively, while the basal melt events associated with ocean temperature increase stand out in SIMBA_2015a.   The SIMBA data are available through the Norwegian Polar Institute’s data center (https://data.npolar.no/dataset/6ed9a8ca-95b0-43be-bedf-8176bf56da80) and the method of interface detection is thoroughly described in Provost et al. (2017). Note that all time series have been smoothed with a 36-h running mean.   Provost, C., N. Sennechael, J. Miguet, P. Itkin, A. Rosel, Z. Koenig, N. Villacieros-Robineau, and M. A. Granskog (2017), Observations of flooding and snow-ice formation in a thinner Arctic sea-ice regime during the N-ICE2015 campaign: Influence of basal ice melt and storms, J. Geophys. Res. Oceans, 122, 7115–7134, doi:10.1002/2016JC012011. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

Two ice mass balance instruments (part of IAOOS7 and IAOOS8 platforms) deployed near 83°N on the same ice floe, documented the evolution of snow and ice conditions in the Arctic Ocean north of Svalbard in Jan-Mar 2015. Frequent profiles of temperature (every 3 hours) and temperature change after 30s and 120s heating (once a day) were recorded. The ratio of the temperature changes after heating provides a proxy for thermal diffusivity. Both instruments documented flooding and snow-ice formation. Flooding was clearly detectable in the simultaneous changes in thermal diffusivity proxy, increased temperature, and heat propagation through the underlying ice. Slush then progressively transformed into snow-ice. Flooding resulted from two different processes; i) after storm-induced break-up of snow-loaded floes for IAOOS8 and ii) after loss of buoyancy due to basal ice melt for IAOOS7. The instrument on IAOOS7 documented basal sea-ice melt over warm Atlantic waters and ocean-to-ice heat flux peaked at up to 400 Wm-2 in winter. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

This dataset is associated with the publication by Nicole Couto, Jennifer MacKinnon, Harper Simmons, and Matthew Alford, "Near-bottom baroclinic and submesoscale instability at the Chukchi shelfbreak." Four FastCTD sections and one Modular Microstructure Profiler (MMP) were collected crossing the Chukchi shelf break in September 2018 from the R/V Sikuliaq. Current velocities were measured simultaneously from two hull-mounted ADCPS: an RDI Workhorse 300 kHz and an RDI Ocean Surveyor 75 kHz. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

The mooring was deployed on 15 September 2017 from Norwegian Research Vessel Lance at 80.6°N and 7.26°E (depth of 730 m) in the Yermak Pass over the Yermak Plateau north of Svalbard. It comprised 3 instruments: an upward-looking RDI 75kHz, a Long Ranger Acoustic Doppler Current Profiler (ADCP) at 340 m with 16 m vertical resolution (25 bins of 16 m each) and a 2-hour sampling time; a Seabird SBE37 measuring temperature, salinity and pressure at 348 m with 10-minute sampling time; and an Aquadopp current meter at 645 m with a 2-hour sampling time. The mooring was retrieved on the 19 July 2020 by Norwegian Icebreaker K.V. Svalbard. The present dataset features: (i) the ADCP 50-hour smoothed daily velocities, conservative temperature and pressure time series interpolated every 10 meters within the 20-330m layer, (ii) the Aquadopp 50-hour smoothed daily velocities and pressure time series at 645 m; and (iii) the SBE37 50-hour smoothed daily conservative temperature, absolute salinity and pressure time series at 348 m. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

As part of the STeP project (STorfjorden Polynya multidisciplinary study), two moorings, M1 and M2, were deployed in Storfjorden (Svalbard) on July 14, 2016 from the French R/V L’Atalante and were recovered one year later, on September 28, 2017, from the French R/V Pourquoi-Pas?. The two moorings, deployed a few hundred meters apart at 78°N and 20°E at a depth of 100m, documented the formation of dense Brine-enriched Shelf Water (BSW).  The moorings included both physical oceanography (PO) and biogeochemistry sensors. The present dataset is composed of PO data only: the 3 components of the currents, backscatter, salinity, temperature and dissolved oxygen. PO sensors on M1, spanning the whole water column, included 6 Seabird SBE37 microcat (CTD),  15 RBR solo (T), and 1 RBR duet (TD) for hydrography, while currents were monitored with a RDI WH 300kHz upward looking ADCP and 1 Nortek Aquadopp underneath. PO sensors on the shorter M2 mooring included 1 Seabird SBE63 (CTD-O2), 1 RBR solo (T) and 1 RBR duo (TD). Data have been calibrated and validated and the different steps of this processing are discussed in the technical report provided with the dataset. Two netcdf4 files are provided for M1: one for hydrography (STEP2016_M1_hydrography.nc), the other one (STEP2016_M1_current.nc)  for currents and backscatter. Only one netcdf4 files (STEP2016_M2_hydrography.nc) is provided for the shorter M2. Temperature and salinity data from SBE sensors have been interpolated on a common time grid with a 20’ time step. Likewise temperature data from RBR are provided on a 30” time grid. A merged SBE-RBR dataset has also been built for increased vertical resolution, providing temperature every 20’. ADCP data are provided on a 100’ time grid. The user is referred to the technical report provided with the dataset for further information on the different fields. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

The two platforms IAOOS 23 and IAOOS 24 were deployed within 600 m from each other at the North Pole from the Russia-operated Barneo ice camp on April 12, 2017. They followed a meandering trajectory, reaching as far as 30°E in the Nansen Basin, before turning back to the western Fram Strait. On both IAOOS 23 and 24, the ocean profiler was a PROVOR SPI (from French manufacturer NKE) equipped with a Seabird SBE41 CTD (Conductivity, Temperature, Depth) and a dissolved oxygen (DO) Aandera 4330 optode. For the first time, the profiler on IAOOS 23 also carried biogeochemical sensors. It featured a bio-optics sensor suite and a submersible ultraviolet nitrate analyzer (SUNA, Satlantic-Seabird Inc.). The bio-optics sensor suite (called Pack Rem A) combines a three-optical-sensor instrument (ECO Triplet, WET Labs Inc.) and a multispectral radiometer (OCR-504, Satlantic Inc.). The present dataset is composed of CTD-DO data from IAOOS 23 and 24, corrected from the thermal lag and the sensor lag, despiked and interpolated vertically every 0.5 m. It also comprises nitrate concentrations from the SUNA and CDOM fluorescence from the WETLabs ECO sensor on IAOOS 23. Other biogeochemical data will be added to this dataset. The profilers were set to perform two upward profiles a day from 250 m (IAOOS 23) and 350 m (IAOOS 24) upward starting at approximately 6 am and 6 pm. They provided a unique 8-month long dataset, gathering a total of 793 profiles of the temperature, salinity and oxygen (upper 350m) and 427 profiles of CDOM and nitrates concentrations (upper 250m).   Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

IAOOS14, IAOOS15 and IAOOS25 were deployed from the Korean Icebreaker R/V Araon during cruises in the northern Chukchi Sea. IAOOS14 and IAOOS15 were deployed 300 m apart on the same floe on 12 August 2015 in the Makarov Basin (80.8°N;173°E) and they drifted together remaining always less than 6 km apart. IAOOS25 was deployed on 15 August 2017 south-west Mendeleev Ridge (77.7°N;180°E) and drifted westward to the continental slope of the East Siberian Sea. IAOOS14 and IAOOS25 stopped transmitting on 9 October 2015 and 19 November 2017 respectively, likely due to the loss of their profilers while crossing relatively shallow bathymetry. IAOOS15 dataset ends in 15 October 2015. Ocean profilers were PROVOR SPI (from French manufacturer NKE) equipped with a Seabird SBE41 CTD (Conductivity, Temperature, Depth) and a dissolved oxygen (DO) Aandera 4330 optode. The profilers were set to perform two upward profiles a day from 800 m (IAOOS 14), 300 m (IAOOS 15) and 420 m (IAOOS 25), upward starting at approximately 6 am and 6 pm. The present dataset is composed of CTD-DO data from IAOOS 14 and 15, and CTD data from IAOOS 25 in the Makarov Basin, corrected from salinity errors and interpolated vertically every 0.5 m. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

In the Northwest Atlantic, Pandalus borealis (northern shrimp) serve as key mid-trophic consumers and prey for higher-trophic predators, including commercially important fish species. However, the impact of changing environmental conditions on trophic interactions and lipid storage in sub-Arctic ecosystems is not well understood. We employed biochemical tracers (fatty acids and stable isotopes) to investigate the trophic ecology and stage-specific nutritional condition of P. borealis across spatial and seasonal scales. A total of 68 different fatty acids (FAs) were identified in P. borealis tissues (i.e., muscle and eggs). The relative abundances of these FAs varied among sex, tissues, seasons, and fishing areas. Results revealed that P. borealis primarily fed on diatoms and zooplankton, with opportunistic feeding on sinking phytodetritus. Lipid composition showed strong seasonality, with storage triacylglycerols being the predominant lipid class. Ovigerous females exhibited the highest lipid concentrations and essential fatty acids, emphasizing the ecological importance of eggs as high-quality lipid sources. Additionally, total lipid content in eggs increased from spring to summer, highlighting vulnerability to shifts in seasonal primary production. This study underscores the significant seasonal variability in the nutritional status of P. borealis and the need to understand lipid dynamics to assess population resilience to environmental changes. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

We gathered ocean profiles during the first two floes of the N-ICE2015 ice camp north of Svalbard with IAOOS ocean profilers. Between January and March 2015, four ocean profilers were deployed: two below a full IAOOS platform (500 m long cable) during floe 1, two on an 800 m long instrumented line in a tent-covered testing-hole during floe1 and floe 2. The ocean profilers, from French manufacturer NKE (PROVOR SPI), carried a Seabird SBE41CP CTD (Conductivity, Temperature, Depth) with an Aanderaa 4330 optode for dissolved oxygen (DO). The profilers were set to perform two profiles a day from 500 m upward (800 m from testing hole) starting at 6 am and 6 pm. They provided the first winter data in the region with a total of 138 profiles during floe 1 (January 15- February 21) with 62, 50, and 26 profiles for IAOOS7, IAOOS8, and IAOOS 9, respectively and 16 profiles during floe 2 (February 24 - March 19- IAOOS 11 from testing hole). Following quality control, we retain all the temperature profiles and remove 1% of the salinity profiles. Finally, the accuracy is estimated to be 0.002°C in temperature, and 0.02 g/kg in salinity. Several profiles are missing or incomplete because of high drift speeds (> 0.4 m s-1) impeding the ascent of the profiler. There are no bottle DO measurements during Floe 1 to calibrate the DO data. DO accuracy is estimated comparing the deep values of DO concentration (rather stable at 500m) between the three profilers. A difference of 3 µmol L-1 is observed between IAOOS 8 and 9, and IAOOS 7. An offset of 3 µmol L-1 is then applied to the oxygen data from IAOOS7 and the accuracy of the data is estimated to be at ±3 µmol L-1. The vertical resolution of the processed CTD data is 1 dbar in the upper 400 dbars, 5 dbars from 400 to 550 dbars and 10 dbars from 550 to 850 dbars. The vertical resolution in dissolved oxygen is 2 dbars over all depths. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

The dataset represents data primary processing of zoobenthos samples taken in the Chaun Bay of the East Siberian Sea in October 2020 during an expedition onboard R/V "Akademik Oparin" Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.