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.

This dataset contains turbidity (NTU) data acquired between August 2018 and June 2019 using a Wetlabs turbidimeter (ECO-BBRTD, serial # 215R) installed horizontally at 1.5 m height at the top of the SeaMoN East frame. The sensor was not calibrated as the sizes of the natural particles are unknown. Data was acquired every 15 minutes. The instrument is part of the SeaMoN East ecological monitoring node deployed at ca 10m away from the active hydrothermal edifice Tour Eiffel. Deployment : 2018/08/23 -Victor 6000 Dive 707-12 (Momarsat 2018 cruise https://doi.org/10.17600/18000514) Recovery : 2019/06/15 - Nautile dive 1942-04 (Momarsat 2019 cruise (https://doi.org/10.17600/18001110)-[https://doi.org/10.17600/18000514]) Location : 37.8N, 36.77S, -31.64E, -32.91W   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 contains turbidity, chlorophyll and the associated sensor raw data acquired between July 2017 and August 2018 on EMSO-Azores observatory by the EGIM. Tubidity is one of the 7 core parameters monitored by the (EGIM, EMSO Generic Instrumental Module)-[https://www.emso-fr.org/EMSO-Azores/Sensor-data-sheets/EGIM]. The EGIM prototype was deployed at Lucky Strike hydrothermal vent site, 25 m south west of the active edifice Tour Eiffel, to monitor local hydrodynamic variability and complement the data obtained by the numerous sensors set on this site: oceanographic mooring deployed south of the vent field, the multidisciplinary Seamon East node, autonomous current meters, array of temperature probes… Image Reference: https://www.seanoe.org/data/00454/56525/illustrations/illustration-40.gif. 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 contains dissolved iron concentrations ((Fe(II) + Fe(III); µmol/l) acquired between August 2018 and December 2018 (n=445) using the CHEMINI Fe, a CHEmical MINIaturized analyser (samples taken every 12 hours, with daily in situ calibration using a 20 µmol/l iron standard, Vuillemin et al., 2009). The sample inlet was positioned on the mussel bed at the base of the Tour Eiffel edifice of the Lucky Strike hydrothermal vent (1695 depth).CHEMINI Fe (CF2) was mounted on the TEMPO module which was itself connected to the SeaMON East node of the EMSO-Azores observatory. 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 contains real-time total dissolved iron concentrations ((Fe(II) + Fe(III); µmol/l) acquired from the EMSO-Azores seafloor observatory TEMPO from July 2011 to March 2012 (n=1780). Data are purchased by the CHEMINI Fe (CF0), a CHEmical MINIaturized analyser dedicated to in situ determination of iron concentrations (every 12 hours, without in situ calibration, Vuillemin et al., 2009). The instrument is deployed on TEMPO part of Seamon East environmental monitoring node. The sample inlet is located on a mussel bed at the base of the Eiffel Edifice at 1695m depth. 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 contains turbidity (NTU) data acquired between July 2017 and July 2018 using a Wetlabs turbidimeter (ECO-BBRTD, serial # 215R) installed horizontally at 1.5 m height at the top of the SeaMoN East frame. The sensor was not calibrated as the sizes of the natural particles are unknown. Data was acquired every 15 minutes. The instrument is part of the SeaMoN East ecological monitoring node deployed at ca 10m away from the active hydrothermal edifice Tour Eiffel.. 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.