The data compiled and obtained during this project contributed to filling identified knowledge gaps on the characterization of the deep-sea marine biodiversity (<1,000 m depth) until the outer limit of the Azores sub-area of the Portuguese EEZ, in terms of species, communities and habitats present there. The project contributed to a better definition of deep-sea habitat typologies, including the definition of Vulnerable Marine Ecosystems. A key aspect was mapping the spatial distribution of deep-sea species, communities and habitats until the outer limit of the Azores sub-area of the Portuguese EEZ and the identification of areas that fit the definition of VMEs in the Azores. The project also supported information that enables national and international reporting, regarding environmental policies for the marine environment, by the Autonomous Region of the Azores. Finally, we demonstrated and tested low-cost tools to support monitoring the environmental status of the deep sea, up to the outer limit of the Azores sub-area of the Portuguese EEZ.

1. Existing datasets: After the exhaustive compilation of data on the deep-sea biodiversity of the Azores down to 1,000 m depth we produced georeferenced database with the respective metadata, following the interoperability recommendations of regional authorities, as well as international harmonization standards. On November 1st 2023, the database compiled contained 60,877 (taxa) plus 1,683 (communities) records of marine biodiversity in the deep sea of the Azores with an emphasis on rates that indicate the presence of VME.
2. Integrative taxonomic approach: Using an integrative taxonomic approach, we have examined 52 specimens across 18 taxa of cold-water corals. This work generated 94 new DNA barcoding consensus sequences (average length 700 bp), and a genome skimming dataset with 9M PE reads per specimen. For the first time a genomic study that combined high-throughput sequencing data from cold-water corals sampled on different sites of the North Atlantic and the Azores was conducted, applying a phylogenomic approach that included 445 taxa. Using this dataset together with diagnosing morphological characters, we have attributed names to seven morphotypes (corals belonging to Paramuriceidae, Keratoisididae, Alcyoniidae) and identified several putative new species. The taxonomic examination of Porifera specimens from COLETA and OceanX 2023 greatly increased the knowledge of the sponge diversity of the Azorean Region, which to date represented a poorly studied group. From a total of 52 analised specimens, 36 species were assigned. Four putative new species and one genus were identified.
3. VME indicator species: The reassessment of the total diversity of cold-water corals in the Azores based on the new information generated accounts for +190 species. This list is likely to grow in the future with increasing deep-sea sampling effort from ROV expeditions. The diversity of sponges in the Azores is reported to be high however this group is little studied. Evaluation of potential VME indicator species identified 27 Octocorallia, 9 Scleractinia, 6 black corals, 3 Stylasterids, and thirteen sponge taxa.
4. VME indicator biological communities: Through visual assessments, 39 associations of conspicuous benthic species have now been identified and catalogued, providing in each case the main structuring taxa (i.e., indicator species). The vast majority of benthic communities identified so far can be included under the category of coral gardens (n= 23), not undervaluing those classified as sponge grounds (n= 9), coral reefs (n= 2), Xenophyophore aggregations (n= 1) and those formed by other taxa (n= 4). From the 39 benthic communities identified from the video images, 25 were considered to fit the criteria for Vulnerable Marine Communities (VMCs).
5. Spatial distributions of deep-sea biological diversity on geomorphological features: The existing underwater video transects down to 1,000 m span the whole EEZ, with 69 in Western Group of the Azores, 49 in the Northern Mid-Atlantic Ridge, 103 in the central Mid-Atlantic Ridge, 47 in the Southern Mid-Atlantic Ridge, 295 in the Northern Central Group of the Azores, 392 in the Southern Central Group of the Azores, and 193 in the Eastern Group of the Azores, and 34 outside the EEZ but in areas of interest. Video footage and annotations have been obtained for all 140 L3 areas. As of 1st November 2023, the database generated from the annotation of the benthic megafauna contains 52,697 records inside of the Azores EEZ. Each of these records corresponds to the occurrence of one OTU in segments of 100 m along each dive, providing an estimated density value using the coding of the SACFOR scale. This database is now a fundamental tool for mapping the distribution of biodiversity and VME indicator taxa within the limits of the Azores EEZ.
6. Vulnerable Marine Ecosystems: We evaluated the 140 geomorphological structures of the Azores in relation to each of the five FAO criteria to define what constitutes a VME, based on the information compiled, collected and analysed during this project. The evaluation was based on the species and communities found in each geomorphological structure as well as a measure of their abundance. The assessment of underwater features against the VME criteria identified 41 out of the 140 areas that could fit the criteria that defines a VME.
7. Evaluating of Descriptor 6: To support the assessments of the Descriptor 6 criteria (D6C3 and D6C5), we carried out an assessment of the degree of pressure and threat relating to human activities. We adopted a standard methodology for this purpose which starts from the characterization and mapping of conservation values and pressures arising from activities and potential uses. We also developed matrices of pressures and threats that allow an objective assessment of impacts and contribute to the assessment of D6C3 and D6C5. The application of the VME and fishing effort portfolio categories identified 22 areas classified as VME that fall in the portfolio category high VME – low VMS, 14 falling in the portfolio category high VME – high VMS, and 3 in the other category. The areas where high fishing effort overlaps with high VME index may be areas of potentially significant adverse impacts in vulnerable marine ecosystems.