The ARCHYD dataset, which have been collected since 1988, represents the longest long-term hydrologic data sets in Arcachon Bay. The objectives of this monitoring programme are to assess the influence of oceanic and continental inputs on the water quality of the bay and their implications on biological processes. It also aims to estimate the effectiveness of management policies in the bay by providing information on trends and/or shifts in pressure, state, and impact variables. Sampling is carried on stations spread across the entire bay, but since 1988, the number and location of stations have changed slightly to better take into account the gradient of ocean and continental inputs. In 2005, the ARCHYD network was reduced to 8 stations that are still sampled by Ifremer to date. All the stations are sampled at a weekly frequency, at midday, alternately around the low spring tide and the high neap tide. Data are complementary to REPHY dataset. Physico-chemical measures include temperature, salinity, turbidity, suspended matters (organic, mineral), dissolved oxygen and dissolved inorganic nutrients (ammonium, nitrite+nitrate, phosphate, silicate). Biological measures include pigment proxies of phytoplankton biomass and state (chlorophyll a and phaeopigment). 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.

MARLEY (Monitoring deep-seA coRaL EcosYstems) is a deep seafloor observing system dedicated to the monitoring of cold-water coral habitats. The system is deployed in the Lampaul canyon off Brittany, France since August 2021 and maintained each year during the ChEReef-Obs cruises. The study site is a coral garden dominated by Madrepora oculata, located on a sedimented platform at 780 m depth. MARLEY is equipped with a CTD SBE 37-SIP, an oxygen optode Aanderaa (4330 or 4831), an ADCP Teledyne RDI Workhorse 300kHz, a turbidity sensor Wetlabs ECO NTU (sensitivity: 0-1000 NTU), a sediment trap Technicap PPS 4/3 – 24 bottles and a camera module. The camera module, which can be moved from up to 30 m from the main station, is equipped with a camera AXIS Q1786, two flash lights and a fluorometer & scattering meter SEA-BIRD ECO FLNTU. All sensors are controlled and synchronised by the Communication and Storage Front-end - 2nd generation (COSTOF2), which is also managing data storage. Optical sensors are protected from fouling by electrochlorination (20 seconds, each 6 hours). The oxygen optode is calibrated each year prior to deployment. These datasets provide raw data from the oxygen optode Aandera 4831, the CTD Seabird SBE37, the Wetlabs ECO NTU and the SEAR-BIRD ECO FLNTU covering the period 28/08/2021 to 19/01/2022, with a frequency of 15 minutes. Data from Wetlabs ECO NTU include raw counts and Nephelometric Turbidity Unit (NTU) derived from manufacturer’s calibration with Scale Factor = 0.0611 and Dark Counts = 50. Data form SEABIRD ECO FLNTU include raw counts at 695 nm (Chlorophyll) and 700 nm (Turbidity). Chlorophyll concentration (µg/l) is derived from manufacturer’s calibration with Scale Factor = 0.0180 and Dark Counts = 48. Nephelometric Turbidity Unit (NTU) is derived from manufacturer’s calibration with Scale Factor = 0.0481 and Dark Counts = 50. 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.

For the mapping of the canyon features a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry has been analysed and interpreted. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the MARCONI, CONTOURIBER and MOWER projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m

For the mapping of the turbiditic fans a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry has been analysed and interpreted. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the ALBA, MARSIBAL, CONTOURIBER and SARAS projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m Publication: Ercilla, G., Juan, C., Hernández-Molina, F. J., Bruno, M., Estrada, F., Alonso, B., ... & Ammar, A. (2016). Significance of bottom currents in deep-sea morphodynamics: an example from the Alboran Sea. Marine Geology, 378, 157-170.

For the mapping of the canyon features a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry has been analysed and interpreted. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the ALBA, MARSIBAL, CONTOURIBER and SARAS projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m Publication: Ercilla, G., Juan, C., Hernández-Molina, F. J., Bruno, M., Estrada, F., Alonso, B., ... & Ammar, A. (2016). Significance of bottom currents in deep-sea morphodynamics: an example from the Alboran Sea. Marine Geology, 378, 157-170.

For the mapping of general landslides we analysed and reinterpreted a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the ALBA, MARSIBAL, CONTOURIBER and SARAS projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m

For the mapping of mass-flow deposits a database with over 1500 km of 2D multi- and single-channel seismic lines, with different degrees of resolution (from a few metres to metric) together with high-resolution multi-beam bathymetry has been analysed and interpreted. Multi-channel seismic records were downloaded from the Archivo Técnico de Hidrocarburos (https:// geoportal.minetur.gob.es/ATHv2/welcome.do). Single-channel records were mostly obtained with airgun systems (140 to 530 c.i.) and are included in the database from the Instituto de Ciencias del Mar, ICM-CSIC, http://www.icm.csic.es/geo/gma/SurveyMaps. Several multi-beam bathymetry datasets obtained with Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders were also compiled and integrated for the present study from the ALBA, MARSIBAL, CONTOURIBER and SARAS projects and the Fishing General Secretary (Spanish Government). These data are gridded to a resolution of 50 m

Narrative: The mapping of the landslides have been carried out base on multibeam bathymetry recorded using Simrad EM12 and Atlas HYDROSWEEP DS multibeam echosounders, during cruises from the Spanish Fishing General Secretary (2003 and 2004) and FAUCES (2018) Project. Morphometric attributes such as slope gradients, profile curvatures, planar curvatures and roughness were obtained by ArcMap (GIS), and topographic profiles allowed us to obtain a better characterization of landslides. Also seismic records with different degrees of penetration (0.5 to 1.5 s) and resolution (from a few metres to decimetres) were analysed for landslide characterization. Publication:Ercilla, G., Galindo-Zaldívar, J., Estrada, F., Valencia, J., Juan, C., Casas, D., ... & Yenes, M. (2022). Understanding the complex geomorphology of a deep sea area affected by continental tectonic indentation: The case of the Gulf of Vera (Western Mediterranean). Geomorphology, 402, 108126.

The seismic profile was obtained in order to map of the morphological features and analyses the geomorphology, stratigraphy, sedimentology and tectonics in the oil tanker Prestige wreck area to determine the potential geological hazards

The seismic profile was obtained in order to map of the morphological features and analyses the geomorphology, stratigraphy, sedimentology and tectonics in the oil tanker Prestige wreck area to determine the potential geological hazards