Unveiling the deep ocean warming: observed bottom ocean dataset across Mediterranean Sea

The deep ocean was long assumed to be in a quasi-stationary state, and therefore excluded from studies on climate variability. The awareness of the unsteady state of the deep ocean is a fairly recent achievement, but despite its pivotal role in the assessment of climate variability, the understanding of abyssal ocean dynamics remains largely unknown, primarily due to the scarcity of observations. This is why any observations below 2000 m depth, although poor or widely dispersed, constitute valuable knowledge that is mandatory to enhance and make available. This work presents validated oceanographic time series collected by benthic multidisciplinary observatories across key locations in the Mediterranean Sea region. It includes details on the data processing and quality control methods used to ensure reliability and aims to deliver high-quality data, as well as standardization in the quality control procedures for deep-sea measurements. The dataset provides a comprehensive description of seafloor observations collected over different time periods during the past decade, contributing to the long-term characterization and understanding of abyssal ocean variability in the region (MOIST, https://doi.org/10.13127/MD/MOIST, Azzarone et al., 2010).