A 2-year dataset of a stand-alone mooring, deployed in November 2020 down the Levante Canyon in the eastern Ligurian Sea, is presented. The Levante Canyon Mooring (LCM) is a deep submarine multidisciplinary observatory positioned at 608 m depth in a key ecosystem area. The Levante Canyon hosts a valuable and vulnerable ecosystem of deep-living cold-water corals (CWCs), studied and monitored since 2013 through integrated mapping of the seabed and water column. The 2-year dataset, acquired on the mooring and presented here (data from November 2020 to October 2022), includes measurements conducted with both current meters and conductivity–temperature–depth (CTD) probes and provides information about the hydrodynamics and thermohaline properties across almost the entire water column. The observatory is still ongoing, and the dataset is regularly updated. All the described data are publicly available from https://doi.org/10.17882/92236 (Borghini et al., 2022). They must therefore be preserved and are of considerable scientific interest.

The warming trend of the Mediterranean region is already well known, but there is still a lack of information on its seasonal/annual to multidecadal time scales and its distribution in all water masses, including deep water. New temporal and spatial evidence of this thermal variability has been presented in the Tyrrhenian Sea, thanks to twenty-year continuous monitoring by eXpendable BathyThermographs (XBTs) along a fixed route from Genoa to Palermo. The Tyrrhenian Sea is one of the deepest Mediterranean sub-basins (with a maximum depth of about 4000 m), but its interaction with neighbouring basins is controlled by topographical factors, such as the Sardinian Channel to the south and the Corsican Channel to the north. The way in which the warm signal, originating from the Levantine sub-basin, and entering from the south, affects the entire Tyrrhenian Basin spreading rapidly northwards is studied, considering its peculiarities, such as topography, surface circulation, and strong stratification, as well as its climate variability. The warming trend observed for the Tyrrhenian Sea is consistent with the trend for the Mediterranean Sea as a whole. However, the Tyrrhenian Sea shows some peculiar features: around 2014, a shift to a new equilibrium (warmer) state was detected, with mean values along the monitored route that were significantly higher than the previous period (from 1999 to 2013), especially for the subsurface level, from 100 to 450 m depth.

Climate change investigation, protection of marine ecosystems and mitigation of natural risks are the main research objectives of the Levante Canyon Mooring (LCM), a deep submarine multidisciplinary observatory, installed in September 2019 in the Eastern Ligurian Sea (Lat 44°05.443'N, Long 009°29.900'E at 608 m depth), inside the Pelagos Sanctuary. The observatory consists of a stand-alone station, with an instrumented mooring line ending with a submerged buoy. It operates in delayed-mode and is equipped with sensors that measure physical and biogeochemical parameters continuously and it is expected to provide data in the long-term. Temperature and salinity monitoring is carried out at three depth levels (about 80, 335 and 580 m depth), while turbidity is recorded at 580 m depth. LCM is also equipped with a sediment trap and two acoustic current profilers, able to measure direction and speed of currents in nearly the entire water column.Data will be used to measure flux of sediments, nutrients and organic matter and to better understand the hydrodynamic and physical conditions of the Levante Canyon, which hosts valuable and vulnerable ecosystems, such as the deep-living cold-water corals, identified by IIM and ENEA in 2014, near the LCM mooring site. The LCM site is also located in an area where surface currents are monitored in near-real time by the CNR’s High Frequency Radar network, allowing data integration from multiplatform observations.The project, co-financed by the Liguria Region, is coordinated by the DLTM in strict collaboration, in terms of human resources, infrastructures and instruments with the associated public research bodies (CNR, ENEA, INGV) and with the IIM. The project also includes the next deployment of a cabled station in the Gulf of La Spezia (10 m depth, less than 100 m far from the coast) that will monitor the gravimetric field, temperature and marine current. The main objective of the coastal station is to provide a test site for new instruments and sensors.

The Mediterranean Sea is experiencing rapid environmental changes, underscoring the urgent need for high-quality, long-term datasets to quantify trends and assess impacts on biogeochemical cycles. Over the past few years, a lot of work has been done to improve and ensure data quality in the western Mediterranean Sea (WMED), but reliable dissolved oxygen (O₂) data remain scarce. This is a critical gap as oxygen is a key indicator of marine ecosystem health and plays a central role in carbon and nutrient cycling. To address this gap, we compiled and rigorously quality-controlled a new regional-scale WMED dataset of O₂ data from sensors mounted on conductivity, temperature, and depth (CTD) probes: CTD-O₂WMED. This product includes over 1000 previously unpublished high-resolution vertical profiles of CTD-O₂ measurements mostly collected within Italian cruises between 2004 and 2023. The quality control (QC) process involved sensor post-calibration against discrete Winkler measurements, primary screening, and a secondary check based on crossover analysis with reference datasets. Combined, this ensures the consistency of the final corrected CTD-O₂WMED across both space and time. CTD-O₂WMED provides a robust observational foundation for assessing trends of dissolved oxygen variability, mainly associated with climate change, anomalies related to deoxygenation processes, and contributes to advancing our understanding of ventilation processes in the WMED. It also serves as a benchmark for calibrating Biogeochemical-Argo floats and for validating regional biogeochemical models. The dataset is publicly available at https://doi.org/10.1594/PANGAEA.982858 (Belgacem et al., 2025).

Current measurements in the open sea are generally acquired by Acoustic Doppler Current Profilers (ADCPs). In the case of ADCPs mounted on spar buoy, current profiles require to be post-processed, to properly take into account the buoy influence: in fact, ADCP compass may reflect alterations induced by the metal structure of the buoy and apparent currents can occur due to the large displacement of the platform. Uncertainty analysis is finally required to properly consider both these effects and to compute robust velocity estimates. A new methodology is tested for a measurement station in the Ligurian Sea, where an ADCP was mounted on the surface buoy of the W1-M3A (Western 1 Mediterranean Moored Multisensor Array) oceanographic observatory, facing upwards at the depth of about 40 m. Marine current numerical models and historical data in the area have been used as a basis for comparison to test the consistency of the proposed method. A very good agreement is obtained. Only minor discrepancies are reported (e.g., monthly averages from the reference model slightly underestimate the west-east current component along the entire profile), but, in general, the application of the proposed methodology ensures that the spar buoy-mounted ADCP system is able to provide reliable measurements for oceanographic studies and validation of 3D hydrodynamic models.