This dataset includes in situ observations of CTD casts collected during the PRE-SWOT experiment.

The East Sea Real-time Ocean Buoy (ESROB) is a surface mooring that has been in operation off the mid-east coast of Korea since 1999. The ESROB is 9 km off the coast (37° 32.24’N; 129° 12.92’E) in a water depth of 130 m, and provides meteorological and oceanographic (physical and biogeochemical) data every 10 min from Conductivity-Temperature-Depth (CTD) and acoustic Doppler current profiler (ADCP) instruments. The data provided here were collected between 2016 and 2020 and follow the data collected by previous publications. The data were quality controlled and assured using typical data processing methods, and have been used to address temporal variations in currents and water properties, as well as wind-and tide-induced internal waves. The uploaded data files contain variables in a NetCDF format that were obtained during each deployment. 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.

RESOLAG is a sensor network located in French Polynesia, in the middle of the South Pacific Ocean. The program started in 2018 to acquire data on seawater parameter inside lagoon impacted by pearl oyster farming activity. It is a long-term monitoring of seawater temperature, disolve oxygen, turbidity, fluorescence and salinity. One of the network’s major goal is to better understand the link between black-pearl oysters and their environment, in order to improve management of the farming activity. RESOLAG was created by the Department for Marine Ressources Management of French Polynesia. It is a public organisation run by the gouvernment of French Polynesia. Therefore all data from the network are publicly available to download (under CC-BY licence). 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 CARBO-ACID research cruise (EUROFLEETS+ SEA02_10) was carried out on the RV Ramón Margalef between August 2nd and August 11st, with departing from Vigo – Spain and ending in Lisbon – Portugal. The main objective of this cruise was to collect data and samples to study the potential effects of ocean acidification on carbonate marine organisms (coccolithophores, pteropods, planktonic and benthic foraminifera, and corals) along the Iberian margin. With this objective, oceanographic data and water samples, plankton, cold-water corals and sediment samples were collected during an upwelling season, along two transects coinciding with the two persistent upwelling filaments off the Iberia Margin: the Cape Finisterra and the Cape Roca. In this dataset is guiven all the acquired data recollected onboad.  During the CARBO-ACID cruise we did a total of 7 stations, 4 stations along the Cape Finisterra transect (from W to E: CA3, CA2, CA7, CA8) and 3 stations at the Cape Roca (from W to E: CA6, CA5, CA4) transect (Fig). At each station we usually started with a multibeam survey, a CTD and Rosette cast. These initial operations allowed to identify the different water masses present in this area, characterize their physical properties and to recover seawater samples at specific depth levels. The seawater samples were onboard subsampled, preserved in cold conditions or with chemicals and/ or filtered for several further analysis in the shore-based laboratories: DNA, chlorophyll, fitoplankton, coccolithophores, pH, alkalinity, stable isotopic composition, trace elements concentration and Suspend Particulate Matter. Subsequently to these operations, at each station, two vertical tows with a plankton multinet (with 5 nets) were done on the top 700 m of the water column to sample the planktonic communities of the different water depths. After this, sediment samples were recovered with a box-corer to study the past oceanographic conditions, between the pre-industrial Era and the Present, with multi-proxies used in paleoceanography and sedimentology. A total of 10 box-cores were recollected and each of them was onboard sub-sampled for eDNA, enzymes and benthic foraminifera. Fifteen shipek grab samples were recollected at the Fontanelas seamount (Estremadura Spur), station CA6, to characterize the sedimentary cover and to evaluate the presence of deep cold-water corals. Preliminary results show that the stations CA7, CA8 and CA4, located close to the coast, as expected, are the most influenced by the coastal upwelling, exhibiting colder surface water, higher values of fluorescence, and more zooplankton content reflecting higher phyto-zooplankton concentrations, as typical of the upwelling waters. At station CA4 temperature was higher and fluorescence showed lower values, indicative of less phytoplankton, and interpreted as indicating a different upwelling source water from that upwelled further north. Based on the CTD data, the Cape Roca transect is more influenced by the subtropical East North Atlantic Central Water (ENACWst), while the Cape Finisterra transect is more under the influence of the subpolar branch (ENACWsp). Seafloor sediment samples showed significant differences between the stations. Along the northern transect (Cape Finisterra) the seafloor sediments show an increase in grain size from the offshore to the coast. The offshore stations CA3 and CA2 revealed finer grained sediments, CA8 were composed of coarser sand and the station CA7, the shallowest station 77 m, presented the sediment composed mainly of shell fragments and coarse grain sand. Along the southern transect (Cape Roca), the offshore station CA6 (Fontanelas seamount) has coarser sandy sediments with rock clasts and cold-water coral fragments, and the stations CA5 and CA4 with fine sand to muddy sediments. The detailed CA6 bathymetry allowed to verify the existence of small plateaus on the slope of the Fontanelas seamount, where the fossil cold-water corals fragments were found, suggesting that this area is a very interesting system deserving further study with a ROV, and to characterize the corals fields and verify if there are live corals. These recollected data and samples will allow not only to reconstruct the pH variability under different environmental conditions, but also to estimate the biogeochemical changes along the coastal ocean waters as the anthropogenic influence increases. These results will contribute to better understand and model the effects on the biota under the future expected oceans pH 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.

Hydrographic conditions along a northeastern section off the eastern coast of Qatar Peninsula, Arabian Gulf were measured seasonally for the first time. Six sampling stations, along a 105-km section perpendicular to the major axis of the Gulf, were visited five times within one year (October 2012, January 2013, April 2013, June 2013, and August 2013) to investigate seasonal and spatial variations in hydrographic conditions of Qatar’s exclusive economic zone. 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.

An intensive study at a mussel farm at Tångesund 2016-2017. Here, the connection between the stratification of the water mass, currents, the presence of harmful algae and the presence of algal toxins in mussels will be investigated. A coastal buoy was placed next to the mussel farm with sensors for temperature, salt and oxygen at five different depths. At the surface there was also be a sensor for chlorophyll and turbidity.

Data were collected in the southern Western Black Sea (Bulgarian and Romanian territorial waters) for the Eurofleets+ PHYCOB cruise. This submission contains CTD and nutrient data. The main scientific objectives of the research cruise are: 1) To assess the presence of toxic microalgae in the plankton assemblage of the Western Black Sea. 2) To quantitatively determine the spatial distribution of toxic phytoplankton species and their corresponding toxins in the plankton. 3) To quantitatively describe the spatial distribution of toxic phytoplankton resting stages in surface sediments and determine hotspots of recruitment and bloom initiation. 4) To define correlations among hydrographic and/or meteorological conditions and occurrence of HAB species. 5) To characterize the plankton communities accompanying HAB species together with toxin analysis of size fractionated samples. 6) To identify heterotrophic dinoflagellates, ciliates, or other small zooplankton as possible toxin vectors. 7) To isolate toxic Black Sea microalgal species and establish monoclonal cultures for characterization of Black Sea strains. 8) To perform an interseasonal comparison of toxigenic plankton species by combining the data sets collected during the R/V Akademik cruise that was performed in May/June 2019 with our data from summer. 9) To compare the data set from the Western Black Sea to the Southern (North-) Western North Sea, Baltic Sea and West Greenland obtained during earlier expeditions for site comparisons.

Data collected during the BENCHMARK cruise. The cruise was carried out between August 1-10, 2021 on Denmark Strait, in Icelandic and Greenlandic waters. The objectives of the cruise were to characterise the composition and distribution of epibenthic fauna in the Denmark Strait, with a particular focus on taxa considered indicators of Vulnerable Marine Ecosystem, and to survey water mass properties and flow structure in the area.

The RV Arni Fredriksson collected simultaneous information on hydrology, prey and Brunnichs/common guillemot from 18 to 25/06/2022 in north-west Iceland. 5 transects of 60km length were succesfully completed twice in shelf-waters. A 6th transect of ~ 40km length was performed once in Arnarfjordur. During transects, 2 observers recorded the 2D distribution of all seabirds using European Seabird At-Sea (ESAS) methodology. At the same time, a scientific echosounder (Simrad EK80) operating at 5 frequencies (18, 38, 70, 120, 200 Khz) recorded the 3D distribution of fish. 22 trawls (plankton, midwater and demersal) were performed in response to schools and layers detected in the scientific echosounder, offering insights into their species composition and length-frequencies. 107 CTDs were performed at intervals along transects to measure the 3D variation in temperature, salinity, flourescene and turbidity.

Physical data associated with the ABRACO cruise. The ABRACOS (Acoustics along the BRAzilian COaSt) cruise aims to begin an integrated approach to monitoring the tropical marine ecosystems in the Brazilian Nordeste region in order to better understand the connectivity between the sub-systems composing it. In particular, this cruise should fill this gap and improve understanding of the degree of connectivity which exists between the oceanic islands and the continental margin in the Nordeste of Brazil, as well as within the continental platform. In this context, the main objective of the ABRACOS cruise consisted in drawing up a 3D characterization of abiotic and biotic compartments and their interactions in the Brazilian Nordeste. Specific objectives: Objective 1 - Characterization of island and coastal dynamics. Measurement of hydrological characteristics and currents (rosette, CTD, ADCP) should enable the circulation and characteristics of water masses to be described. These data will be more specifically used to study the physical connections between 1) the oceanic islands and coastal ecosystems and 2) the coast along the ocean and coastal zones. The in-situ measurements obtained will also be used to validate high resolution regional hydrodynamic models (e.g. ROMS model) which will be implemented. In-situ data acquired during the ABRACOS cruise will be supplemented by satellite data for sea surface heights (e.g. AVISO), surface temperature and chlorophyll (e.g. MODIS) and wind (e.g. ASCAT). However, it should be noted that the resolution of the products usually used and land-ocean interferences on altimetry and backscatter data will not allow these products to be used at less than 30-50 km from the coast. We will be able to partially eliminate this problem by using new "alongtrack" processing of altimetric data performed by the Center for Topographic studies of the Ocean and Hydrosphere in Toulouse. These data will be used to document the geostrophic (from sea level) ageostrophic (from wind) components of surface circulation and their variability in coastal zones. Objective 2 - Ecosystem acoustics. Acoustic tools can provide the simultaneous acquisition of quantitative and qualitative data, at different spatial-temporal scales, in numerous biotic and abiotic compartments of an ecosystem. These data can be used to characterize the ecosystem in three dimensions and directly study interactions between compartments. Active acoustics have rarely been used in tropical coastal zones. The multifrequency (38, 70, 120, and 200 kHz) acoustic data acquired during the ABRACOS cruise will be used to create an initial 3D characterization of island and coastal ecosystems in the Brazilian Nordeste region, simultaneously characterizing the seabed and water column, when possible. The French team proposing this has sound experience in the field and developed the open source 'Echopen' software in Brest (www.france-nord.ird.fr/lesressources/outils-informatiques) which can separate the various sources of acoustic echoes (e.g. zooplankton, gelatinous organisms and fish) from multifrequency acoustic data. In order to calibrate the 'Echopen Brésil' version, acoustic observations from the ABRACOS cruise must be combined with sampling using micronekton, mesopelagic and bottom trawls (Leg 2 only) and sampling of zooplankton at fixed stations (bongo and WP2 plankton nets and phytoplankton nets). To validate the 'Echopen substrat' tool we will use sampling done with bottom trawl, substrate grab and video camera observations. Objective 3 - Biodiversity and trophic structure. As indicated, acoustic observations will be complemented by in-situ sampling of planktonic, pelagic (mid-water trawls) and demersal-benthic (bottom trawl) organisms. This will involve establishing how hydrological conditions determine the vertical distribution of organisms and therefore interactions. One part of the sampled organisms will be conserved in formaldehyde then identified by taxonomists at the Federal university of Rio de Janeiro (UFRJ) to be added to Brazilian collections. The remainder of the samples will be used to obtain biological information. Along with the classic biological measurements (size, weight, sex, maturity, etc.) specimens of entire organisms (plankton) and soft tissues (muscles) will be taken in order to titrate various trophic tracers: stable isotopes of carbon, nitrogen and insofar as possible mercury. In addition, particulate organic matter (POM) will be collected by filtration (samples taken by rosette) to titrate the amounts of stable isotopes. Spatial variations in these tracers will make it possible to highlight the relative positions of these organisms in the food web and variations in food sources through the local POM signatures. Measurements of methylmercury (MeHg), a neurotoxin which accumulates in the food chain, will also be performed on part of the samples used for stable isotopes. The related projects are ABRACOS and Action Incitative IRD "DANOB". 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.