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We analyzed litter occurrence in 68 underwater video transects performed on the middle/outer continental shelf and submarine canyon off Cap de Creus (NW Mediterranean), an area recently declared Site of Community Importance (SCI). Low densities of urban litter were registered on the shelf (7.2 items ha−1), increasing in abundance towards the deepest part of the submarine canyon, with 188 items ha−1 below 1000 m depth. We hypothesize that the strong bottom currents that recurrently affect this area efficiently move litter objects from the shelf towards the deep. Of all litter items, approximately 50% had a fishing-related origin, mostly longlines entangled on rocks in the canyon head and discarded trawl nets in deeper areas. Over 10% of cold-water colonies observed had longlines entangled, indicating the harmful effects of such practices over benthic habitats. These results should be considered when designing mitigation measures to reduce litter pollution in Cap de Creus SCI

The last two decades have witnessed a complete shift in our perception of the deep sea, from a homogeneous, mostly muddy and unspoiled seafloor to a vast patchwork of diverse and fragile habitats as well as a reservoir of living resources, both energy and mineral. Growing and concomitant awareness of the potential for blue growth and vulnerability of deep-sea ecosystems triggered the implementation of management measures and Marine Spatial Planning (MSP) at national, regional and international levels, which are now cumulating in the UN Decade of Ocean Science for Sustainable Development and the International Conference on Marine Biodiversity of Areas Beyond National Jurisdiction (ABNJ). Based on the best available knowledge collated and produced in the framework of ATLAS, the objective of the present deliverable was to integrate all available data into a common analytical framework for systematic conservation planning at the scale of the North Atlantic. Regional-scale MSP in the deep sea unfortunately suffers from a lack of knowledge on the distribution of species and habitats. Such large-scale endeavours to date have thus been mainly relying on biogeochemical and physiographic proxies to design networks of marine protected areas. In just three years, ATLAS has taken an unprecedented step forward in synthesising the data available for the North Atlantic on the distribution of the most vulnerable deep-sea habitats where fragile and long-lived engineering species, such as corals and sponges, are aggregating. Such a synthesis has been enabled through trans-Atlantic collaboration. The 13 case studies (CS), evenly distributed from north to south and east to west of the northern Atlantic, provided new discoveries of deep-sea vulnerable habitats off Greenland, in the Alboran Sea and the Gulf of Cádiz, as well as on Formigas and Tropic seamounts. Beyond new discoveries, ATLAS CS confirmed and improved knowledge on the distribution, ecology and functionality of those vulnerable habitats in the North Atlantic. For Case Study 1 – LoVe Observatory, 1417 records of Lophelia pertusa coral reefs along the Norwegian coast are included. For Case Study 6 - Bay of Biscay, a total of 450 records of 12 different VME types, including coral reefs, coral rubbles, scleractinians, Antipatharians, gorgonians, seapens or pennatulids, mixed corals, aggregation of actiniarians, sponge community and Xenophyophores, are reported. For Case Study 7, VMEs are reported for two areas: 1) for Seco de los Olivos, in the Alboran Sea, 17 VMEs that include sea pen fields, deep-sea sponge aggregations and diverse coral gardens are reported, and 2) for the Volcano of Gazul, in the Gulf of Cádiz, 16 VMEs are reported, that include diverse coral gardens, mud and sand emergent fauna, cold-water coral reef of Lophelia pertusa / Madrepora oculata and deep-sea sponge aggregations. For Case Study 8, VMEs from different areas of the Azores are included: in the Formigas Seamount, 18 VMEs including diverse coral gardens and deep-sea sponge aggregations are reported. Cavalo Seamount, a ridge on the Mid-Atlantic Ridge, Gigante Seamount, Condor Seamount, Dom João de Castro Seamount, and Mar de Prata Seamount also host various coral gardens; the South of Pico Island hosts a deep-sea sponge aggregation of Pheronema carpenteri. The newly discovered Hydrothermal Vent Luso is also reported as a VME for the Azores. For Case Study 10 – Davis Strait, Eastern Arctic, 8 VME areas of deep-sea sponges, 5 VME areas of large gorgonian corals, 4 of small gorgonian corals and 13 of sea pens are reported. Under Case Study 10, the only known Lophelia pertusa reef in Greenland waters is also reported. For Case Study 11 – Flemish Cap, three VME types were identified by the Northwest Atlantic Fisheries Organization (NAFO) and for each, several VME areas are reported: 13 VME areas for sponges, 6 for sea pens and 7 for large gorgonians. For Case Study 12 - Mid-Atlantic Canyons and SE USA, four VMEs are included: 1) Cape Lookout Coral Banks, dominated by large bioherms built by Lophelia pertusa, 2) Hatteras Middle Slope, a physically and biologically unique area of rugged mini-canyons (composed of consolidated muds), 3) Norfolk Canyon, and 4) Baltimore Canyon and vicinities, two rugged submarine canyons that contain extensive cold-water corals. For Case Study 13 - Tropic Seamount is host to multiple VMEs, including dense patches of reef framework-forming scleractinian, dense aggregations of coral gardens, dense monospecific sponge ground of Poliopogon amadou, mixed deep-sea sponge aggregations, Xenophyophore field, and dense crinoid fields.Knowledge gained from ATLAS CS significantly increases the database of vulnerable marine ecosystem (VME) occurrences in the northern Atlantic but the species that define VMEs have been known about for over a century. In order to get an overview of the distribution of VMEs, data coming from sources as various as historical cruises, by-catch of fisheries surveys and Remotely Operated Vehicle (ROV) surveys must be compiled. The reliability of these data however varies and a confidence index has thus been developed in order to objectively and quantitatively rank the reliability of VME records according to the source of records. The ranking ranges from low, for inferred records, to high, for visually assessed records. In addition, not all VMEs equally meet the criteria of rarity, functional significance, fragility and recovery, which vary according to taxa and the abundance of indicator taxa. A VME index has thus been developed to quantitatively and objectively score the vulnerability of VME records. The VME index and the confidence index have been applied to the records of the VME database created and curated by the joint ICES/NAFO Working Group on Deep-water Ecology (WGDEC). This spatial grid of VME likelihood was completed with the unequivocal VMEs mapped in the ATLAS CS. In general, the VME index provides a simplified, spatially aggregated and weighted estimate of the degree to which an area could be considered to contain VMEs under the Food and Agriculture Organisation of the UN (FAO) definition. The VME index clearly highlights areas where a VME is more likely to occur while the associated estimate of confidence gives an indication of how (un)certain that assessment is. The methodology is transparent, science based and data driven, and the aggregate cells can be explored in greater detail to reveal the individual data points that have contributed to the assessment. It integrates far more information than previous methods and as such, better captures the underlying reasoning for identifying VME areas or benthic deep-sea Ecologically or Biologically Significant Marine Areas (EBSAs). The VME index is expected to be updated each year as new data are submitted and will therefore provide an up to date, repeatable and defensible source upon which to base advice as new information is received. The VME index appears to capture most of the important elements of the VME database. This methodology may be considered as a first step towards a systematic approach for the identification and protection of VMEs and EBSAs in the North Atlantic. Our methodology clearly considered several of the steps proposed by Ardron et al. (2014), namely step 1 on assessing potential VME indicator taxa and habitats in a region, step 3 on considering areas already known for their ecological importance, step 4 on compiling information on the distributions of likely VME indicator species and habitats, step 6 on considering fishing impacts, and step 8 on identify ecologically important areas. However, at least one important aspect of the Ardron et al. (2014) framework is missing in the current VME index which refers to understanding the natural distribution of VMEs before significant impacts occurred. This aspect could be considered in future improvements of the VME index to encompass predicted distribution of VME as discussed in Vierod et al. (2014) and Anderson et al. (2016b). Systematic conservation planning is an explicit, objective-based and quantitative approach for allocating areas for biodiversity conservation, for instance used in Marine Protected Area (MPA) networks design process. It aims to identify priority areas answering specific conservation objectives for each considered species or habitat, whilst minimising the socioeconomic costs of conservation over the study area. For the purpose of systematic conservation planning, data on known or inferred VMEs are still too sparse at the scale of the northern Atlantic. The spatial prioritisation developed here aimed to identify zones of conservation importance for seabed species and habitats associated with VMEs in a comprehensive approach, by complementing the records of unequivocal VMEs and the VME likelihood over the basin resulting from the VME index with supplementary information targeting deep-sea species and habitats. ATLAS modelled the present and future distributions of six coral species indicators of VMEs as well as six exploited fish species (D3.3). Through a collaboration with the H2020 Blue Growth SponGES project, the present and future distribution of one sponge species have also been modelled to provide maps of the distribution of key VME indicator taxa with different environmental requirements, life-history strategies and functional significance. The overlap between the present and future distribution of these species under climate change scenarios furtherallowed the mapping of their future climate refugia, constituting resilient areas that were given a high conservation target in simulations. Although the primary focus of ATLAS is on cold-water corals, there is more at stake in terms of conversation in the northern Atlantic. In order to increase the scope of this systematic conservation planning exercise, chemosynthetic ecosystems that qualify as VMEs as well as large physiographic features known to be functional hotspots such as canyons, seamounts and fracture zones have also been considered. Conservation scenarios integrated current management and human activities aspects over the basin, to combine the conservation and socioeconomic stakes during the prioritisation process. While areas already profiting from conservation designations such as fishing closures, MPAs and EBSAs were favoured, areas situated in major bottom-fishing grounds or within deep-sea mining contracts were penalised. In order to suggest a geographically balanced protection network, conservation objectives were replicated within 13 provinces, which considered the main biogeographic and geographical boundaries over the basin as well as a dissociation between broad shallow (800m) habitats. This regionalisation approach ensured a regional replication and representativity of each conservation feature within the main deep-sea biotopes. Finally, this work addressed benthic connectivity aspects, by using the results of larvae drift models to favour connected networks of conservation as best as possible. Emerging from an incremental scenario complexification process, the final simulation (“all management”, Figure 1) resulted in an ecologically coherent conservation network that gave insight into spatial planning possibilities to better protect seabed vulnerable habitats and species. In particular, continental margin slopes, the Mid-Atlantic Ridge, and shelf areas comporting fishing grounds appeared as crucial zones for preserving deep-sea biodiversity (Figure 1). These identified areas comprised of specific habitats (e.g. canyons, ridges, seamounts), concentrating diverse substrates and representing key areas for nutrient circulation, that sustain VMEs and deep-water fish. Even if their depth range is larger, most of the VME indicator taxa used in this study largely occur between 500 and 2500m depths, which were prioritised here. For some species, including gorgonians (Acanella arbuscula, Acanthogorgia armata), scleratinian coral (Lophelia pertusa) and the sponge species (Geodia barretti), future climate refugia are almost exclusively predicted along margin slopes (ATLAS D3.3), that appeared as the most prioritised areas in conservation scenarios. In addition, the Mid-Atlantic Ridge concentrates sites of hydrothermal activity, giving rise to unique chemosynthetic ecosystems. As all known hydrothermal vents south of the Azores Exclusive Economic Zone (EEZ), but also several other VMEs, are located in areas already pre-empted for massive sulphide exploration, these latter contained substantial conservation potential. Identified conservation areas situated within the International Seabed Authority (ISA) contracts could inform the regional management plan to be implemented for preserving the Mid-Atlantic Ridge biodiversity from adverse mining impacts. Finally, the prioritisation results suggest that conservation objectives, especially for demersal fish species, could not be achieved without including large fished areas situated on shelves. This result may promote the development of conservation measures on fishing grounds, from full closures for the most efficient, to species-based catch limitation or minimum fish size. The implementation of such restrictions in EEZs or Regional Fisheries Management Organisations (RFMOs) regulatory areas in Areas Beyond National Jurisdictions (ABNJs) would also contribute to fisheries’ sustainability objectives.Selecting the most prioritised planning units allowed delineation of the main priority areas for deep-sea conservation (Figure 2). Covering approximatively 17% of the study area, these priority areas would answer a relatively high conservation goal for the deep sea, nonetheless they suffer from poor conservation at the moment (Figure 2). Less than 1% of the study area falls into fishing closures and marine reserves that already protect the priority areas for benthic deep-sea ecosystems. For instance, only a few unequivocal VMEs, species climate refugia or canyons currently benefit from some form of protection. In that respect, our systematic planning exercise has shown that, as important as they are, the sum of all Area-Based Management Tools (ABMTs) of the northern Atlantic still suffer from a lack of conservation efficiency, representativity and viability. Moreover, our results highlighted that a more continuous conservation network, displaying corridors or shorter distances between conservation areas, would lead to a more connected and thus more resilient benthic conservation framework. Ultimately, climate change pressures are likely to largely affect deep-sea oceanography and biodiversity, and the ability of current ABMTs to preserve them. Protecting the priority areas herein identified, which hold substantial resilience potential to future environmental changes through the central place of climate refugia in scenarios, could promote the long-term viability of the deep-sea conservation for the North Atlantic.To our knowledge, this study is the first in systematic conservation planning to address the conservation of deep-sea benthic and demersal biodiversity across a whole oceanic basin. These results contribute to the development of systematic approaches for large scale MSP, such as the conservation management of ABNJs currently the object of ongoing international discussions. Lacking of a coordinated framework as well as efficient, permanent and recognised protection measures, the North-Atlantic high seas conservation network could benefit from the suggestions provided by our scientific evaluation. Finally, this basin scale prioritisation will provide general material for local conservation, through a transfer to the MSP work implemented for ATLAS case studies in ATLAS Work Package 6.&nbsp

Seamounts constitute an obstacle to the ocean circulation, modifying it. As a result, a variety of hydrodynamical processes and phenomena may take place over seamounts, among others, flow intensification, current deflection, upwelling, Taylor caps, and internal waves. These oceanographic effects may turn seamounts into very productive ecosystems with high species diversity, and in some cases, are densely populated by benthic organisms, such corals, gorgonians, and sponges. In this study, we describe the oceanographic conditions over seamounts and other underwater features in the path of the Mediterranean Outflow Water (MOW), where populations of benthic suspensions feeders have been observed. Using CTD, LADPC and biochemical measurements carried out in the Ormonde and Formigas seamounts and the Gazul mud volcano (Northeast Atlantic), we show that Taylor caps were not observed in any of the sampled features. However, we point out that the relatively high values of the Brunt–Väisälä frequency in the MOW halocline, in conjunction with the slope of the seamount flanks, set up conditions for the breakout of internal waves and amplification of the currents. This may enhance the vertical mixing, resuspending the organic material deposited on the seafloor and, therefore, increasing the food availability for the communities dominated by benthic suspension feeders. Thus, we hypothesize that internal waves could be improving the conditions for benthic suspension feeders to grow on the slope of seamounts.

Additional figures describing the starting model conditions, more velocity profiles, and changes in resultant velocities around a model coral.

Designing conservation networks requires a well-structured framework for achieving essential objectives such as connectivity, replication or viability, and for considering local management and socioeconomic stakes. Although systematic conservation planning (SCP) approaches are increasingly used to inform such networks, their application remains challenging in large and poorly researched areas. This is especially the case in the deep sea, where SCP has rarely been applied, although growing awareness of the vulnerability of deep-sea ecosystems urges the implementation of conservation measures from local to international levels. This study aims to structure and evaluate a framework for SCP applicable to the deep sea, focusing on the identification of conservation priority networks for vulnerable marine ecosystems (VMEs), such as cold-water coral reefs, sponge grounds, or hydrothermal vents, and for key demersal fish species. Based on multi-objective prioritization, different conservation scenarios were investigated, allowing the impact of key elements such as connectivity and conservation cost to be evaluated. Our results show that continental margin slopes, the Mid-Atlantic Ridge, and deeper areas of large and productive shelves housing fishing grounds appeared as crucial zones for preserving the deep-sea biodiversity of the North Atlantic, and within the limitations imposed by the data available, of the Mediterranean. Using biologically-informed connectivity led to a more continuous and denser conservation network, without increasing the network size. Even when minimizing the overlap with socioeconomic activities, the inclusion of exploited areas was necessary to fulfil conservation objectives. Such areas included continental shelf fishing grounds for demersal fish species, and areas covered by deep-sea mining exploration contracts for hydrothermal vent communities. Covering 17% of the study area and protecting 55% of each feature on average, the identified priority network held a high conservation potential. However, these areas still suffer from poor protection, with 30% of them benefiting from some form of recognition and 11% only from protection against trawling. Integrating them into current marine spatial planning (MSP) discussions could foster the implementation of a basin-scale conservation network for the deep sea. Overall, this work established a framework for developing large-scale systematic planning, useful for managing Areas Beyond National Jurisdiction (ABNJ).

The Gorringe Bank is a seamounts complex located at the eastern tip of the Azores-Gibraltar plate boundary separating Eurasia and Africa. Despite its early discovery at the end of the XIX century, the knowledge of the benthic communities and other associated fauna is still very scarce in this region, particularly in the deep areas below 200 m. The Ormonde seamount is one of the two main summits of Gorringe Bank, which rises from 5000 m to 33 m depth. In this study, we characterised the deep-sea communities in the Ormonde seamount from 900 to 2000 m depth by analysing underwater videos recorded by remotely operated vehicle (ROV) during the MEDWAVES survey (EU H2020 project ATLAS). We provided for the first time, detailed and quantitative information on species composition, densities, spatial distribution and state of conservation compared to other well studied seamounts. The surveyed areas were strongly dominated by sponges, but the presence of patches of cold-water corals were also notable and some other vulnerable marine ecosystems (VMEs) were identified. Spatial patterns in the deep-sea communities were also analysed as a result of the different water masses that bathed the area, exhibiting higher biodiversity in the presence of the Mediterranean Outflow Water (MOW). Studies of deep-sea ecosystems not only improve our knowledge of the deep ocean but also are essential defining an appropriate management plan and conservation measures.

Seamounts are ubiquitous in the global ocean enhancing locally the biological biodiversity in the deep-sea and hosting multiple Vulnerable Marine Ecosystems (VMEs), like cold-water corals (CWCs) and sponge grounds. In the western Mediterranean basin (Alborán Sea), the Seco de Los Olivos Seamount (Chella Bank) is considered a hotspot of deep-sea biodiversity, being part of the protected marine network in Europe (Natura 2000). While previous studies provided extensive qualitative information about what species and habitats occur in the seamount, there is still a challenge to have accurate quantitative information to better understand the spatial distribution patterns of the megabenthic species and its functional role. Using underwater video transects recorded by a Remotely Operated Vehicle (ROV) during the MEDWAVES survey (EU project ATLAS H2020), we quantitatively characterize the megabenthic communities in the Seco de Los Olivos Seamount. A total of 62 operational taxonomic units (OTUs) grouped into five major assemblages were identified, which were mainly associated with the substrate type. The main groups typifying these assemblages included massive sponges, black corals, sea pens, and ray-finned fishes. In addition, taxonomic diversity was evaluated and the patterns observed were also associated with the substrate type and to the flank orientation in a lesser extent. Besides our ecological findings, we found a variety of human impact evidence (e.g., pieces of fishing lines, glass bottles, and trawl marks). Nonetheless, there is a management plan in progress aiming to regulate different human activities (e.g., fisheries) carried out in this area declared a site of ecological importance. Abundances and densities obtained through this study for the most representatives OTUs represent an important contribution to improve our understanding of the biodiversity, ecological associations and potential threats of deep-sea communities and thus, will help to enhance the spatial management and conservation plans for these vulnerable marine ecosystems.

Cabo Verde Islands are located between the North Equatorial Current (NEC) and the North Equatorial Counter Current (NECC). When the NECC reaches Africa, it splits in two currents, an eastward and a northward flow. This later flow joints the NEC forming a front known as the Cabo Verde Frontal Zone, that acts as a barrier between the North Atlantic Central Waters (NACW) and the South Atlantic Central Waters (SACW). In addition, this northward flow produces a cyclonic circulation in the region of Cabo Verde, called the Guinea Dome, and therefore an upwelling in this area. During the iMirabilis2 expedition, 22 CTD cast were performed in order to characterize the hydrographic conditions and to determine the water mass distribution in the main study areas, to find out its effects on the distribution of benthic organisms. Especial attention was put on the characterization of the Cadamosto seamount. Seamounts are underwater mountains which create a perturbation in the oceanic flow. This perturbation under idealized circumstances, known as Taylor columns, has the potential to isolate the oceanic circulation over the summit from the ocean circulation in the open waters. This can lead to the occurrence of upwelling phenomena that enrich the ecosystem. In this work, we show an overview of the preliminary results of the oceanographic studies conducted during the iMirabilis2 expedition.

Comunicación escrita (póster) a Congresos, • Cold-water corals (CWC) form complex 3-D structures that are biodiversity hotspots. However, the knowledge about their ecophysiological response to global change stressors (i.e. warming, acidification, decrease of dissolved oxygen concentration) is still very limited, as well as their possible interactions with local stressors such as the impacts from mining and fishing activities. • Three long-term, multi stressor experiments will explore the combined impact of several environmental and local stressors based on the IPCC projections on different CWC species across the North Atlantic. • Further experiments will include the addition of particles from mining or sediment from trawling activities to all treatments after long-term experiments finish to study the potential physical damage and ecotoxicological effects. • The results from these studies will increase our knowledge on the potential consequences of global change and local stressors and their possible interactions on CWC species and ecosystems that they form. • The results will contribute to support science-based marine spatial planning for the North Atlantic., European Union Commission Horizon 2020 Programa (grant agreement 818123), FEDER ((ACORES-01-0145-FEDER-000140), Ayuntamiento de A Coruña (Spain) and Deep-Sea Biology Society

Many of the marine policy frameworks developed to protect biodiversity in deep-sea areas, including areas beyond national jurisdiction (ABNJ), include indicators to assess policy objectives. These frameworks often have specific guidance on how the indicators should be applied and interpreted. Selection of indicators is an important process and those with strong scientific underpinnings are more likely to produce the expected outcomes. We reviewed three policy and assessment frameworks which include ABNJ regions or were developed specifically for ABNJ: (1) Oslo and Paris Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) ecosystem assessments, (2) the frameworks adopted to implement the UN General Assembly (UNGA) sustainable fisheries resolutions for the management of bottom fisheries to prevent Significant Adverse Impacts on vulnerable marine ecosystems, and (3) the Aichi Biodiversity Targets adopted by Parties to the Convention on Biological Diversity (CBD). We examined whether an assessment approach based on evaluation of Good Environmental Status (GES) under the European Union’s Marine Strategy Framework Directive (MSFD), could be applied to ABNJ. We examined each MSFD descriptor for its applicability to deep-sea habitats considering the work of two European projects concluding that the MSFD could be applied to ABNJ to support OSPAR, UNGA and CBD policy objectives towards a common approach to the assessment of the status of deep-sea ecosystems in ABNJ. In achieving this we also introduce readers outside of Europe to the work conducted within the MSFD.

Circulation patterns in the North Atlantic Ocean have changed and re-organized multiple times over millions of years, influencing the biodiversity, distribution, and connectivity patterns of deep-sea species and ecosystems. In this study, we review the effects of the water mass properties (temperature, salinity, food supply, carbonate chemistry, and oxygen) on deep-sea benthic megafauna (from species to community level) and discussed in future scenarios of climate change. We focus on the key oceanic controls on deep-sea megafauna biodiversity and biogeography patterns. We place particular attention on cold-water corals and sponges, as these are ecosystem-engineering organisms that constitute vulnerable marine ecosystems (VME) with high associated biodiversity. Besides documenting the current state of the knowledge on this topic, a future scenario for water mass properties in the deep North Atlantic basin was predicted. The pace and severity of climate change in the deep-sea will vary across regions. However, predicted water mass properties showed that all regions in the North Atlantic will be exposed to multiple stressors by 2100, experiencing at least one critical change in water temperature (C2C), organic carbon fluxes (reduced up to 50%), ocean acidification (pH reduced up to 0.3), aragonite saturation horizon (shoaling above 1000 m) and/or reduction in dissolved oxygen (>5%). The northernmost regions of the North Atlantic will suffer the greatest impacts. Warmer and more acidic oceans will drastically reduce the suitable habitat for ecosystem-engineers, with severe consequences such as declines in population densities, even compromising their long-term survival, loss of biodiversity and reduced biogeographic distribution that might compromise connectivity at large scales. These effects can be aggravated by reductions in carbon fluxes, particularly in areas where food availability is already limited. Declines in benthic biomass and biodiversity will diminish ecosystem services such as habitat provision, nutrientcycling, etc. This study shows that the deep-sea VME affected by contemporary anthropogenic impacts and with the ongoing climate change impacts are unlikely to withstand additional pressures from more intrusive human activities. This study serves also as a warning to protect these ecosystems through regulations and by tempering the ongoing socio-political drivers for increasing exploitation of marine resources.&nbsp

Outreach is fundamental to disseminate scientific knowledge and approach the general public. The cold-water coral ecosystems are not an exception. During the last 15 years many efforts have been made to make more familiar these complex ecosystems to the society. Technology (which allow the possibility to reach deepest locations) but also the engagement of scientists made this approach possible. In this short contribution we highlight several ways to promote the knowledge and the sensitisation on these fragile deep water ecosystems, showing previous experiences and discussing some ways to effectively transfer the information needed to protect and manage these fragile ecosystems.

The year 2019 marks the 200th anniversary of the birth of Narcís Monturiol, an engineer andinventor behind the development of the first self-propelled manned submersible:Ictineu. Sincethen, submarines have played an important role in marine scientific research. In this work, wewant to give credit to this inventor by sharing the experience of the authors both in the field ofscientific research and education based on the studies performed by the submarineJAGOoverthe seabed of Cap de Creus., L’any 2019 es commemoraren els 200 anys del naixement de Narcís Monturiol, enginyer i inventor,en tant que creador, del primer submarí tripulat de propulsió autònoma: l’Ictineu. Des d’ençà, elssubmarins tingueren i estan tenint un rol cada vegada més rellevant en la recerca científicamarina. En aquest treball volem fer un reconeixement a l’inventor, tot explicant l’experiència delsautors en el camp de la recerca científica i de l’educació a partir dels estudisfets als fons marinsdel cap de Creus amb el submaríJAGO

Seamounts constitute an obstacle to the ocean circulation, modifying it. As a result, a variety of hydrodynamical processes and phenomena may take place over seamounts, among others, flow intensification, current deflection, upwelling, Taylor caps, and internal waves. These oceanographic effects may turn seamounts into very productive ecosystems with high species diversity, and in some cases, are densely populated by benthic organisms, such corals, gorgonians, and sponges. In this study, we describe the oceanographic conditions over seamounts and other underwater features in the path of the Mediterranean Outflow Water (MOW), where populations of benthic suspensions feeders have been observed. Using CTD, LADPC and biochemical measurements carried out in the Ormonde and Formigas seamounts and the Gazul mud volcano (Northeast Atlantic), we show that Taylor caps were not observed in any of the sampled features. However, we point out that the relatively high values of the Brunt–Väisälä frequency in the MOW halocline, in conjunction with the slope of the seamount flanks, set up conditions for the breakout of internal waves and amplification of the currents. This may enhance the vertical mixing, resuspending the organic material deposited on the seafloor and, therefore, increasing the food availability for the communities dominated by benthic suspension feeders. Thus, we hypothesize that internal waves could be improving the conditions for benthic suspension feeders to grow on the slope of seamounts.

The aim of this chapter is to introduce the history of the deepsea and specifically living cold-water coral (CWC) research in the Mediterranean Sea, as well as additional topics that the 46 chapters included in this volume provide to the marine researchers interested in this field. The history of CWC research in the Mediterranean begun in the eighteenth century. Several names stand out in the discovery of the Mediterranean CWCs, but without doubt Jean-Marie Pérès has a special place in the tale of the Mediterranean deep living coral communities, being one of the pioneers of the Mediterranean CWC research. The contributions of Pérès and others are highlighted in this introductory chapter, as well as information about some of the most relevant and pioneering deep-sea scientific expeditions and marine laboratories. In addition, the main topics of each full and short (“drop”) chapters are succinctly discussed while it is also pointed out that large gaps in the knowledge of Mediterranean CWCs still exist (e.g., reproduction, demography). A number of concepts and definitions identified throughout the process of the compilation of this volume were found to respond to multiple meanings potentially resulting in confusion within the CWC research community and thus warranting clarification. In the last part of this introductory chapter, a short reflection is included on aspects that we consider need further research efforts and discussion, such as the major concern on the future of the CWC habitats in the Mediterranean Sea as a result of previous, current and past anthropogenic activities.Despite being separated in three sections (Past, Present and Future) the sections often contain elements of the other ones. The time-line perspective provides better ecological understanding of these deep-sea ecosystems.&nbsp

Occurrence and abundance of deep-water corals in the Levantine Mediterranean Sea is still largely unknown. This is the first attempt to quantitatively describe a Dendrophyllia ramea population discovered in June 2015 during the CYCLAMEN expedition on board the Research Vessel Aegaeo. This population is the deepest ever described until now in the Mediterranean and was found on the outer insular shelf off eastern Cyprus (Protaras, 35°02′N; 34°05′E). Video transects conducted by means of a remotely operated vehicle revealed a well-developed population of D. ramea located on a sandy seabed at 125–170 m depth. The highest density was 6 colonies m−2 and on average 1.6 ± 1.4 (SD) colonies m−2. The population consists of isolated or piled up branches of various sizes and large colonies, some ∼50 cm max width. The corals thrive on soft bottoms, representing a rather novel aspect of the research on D. ramea, since the species is still considered to be mostly associated with rocky substrates. The occurrence of the species in sedimentary grounds makes it especially vulnerable to bottom contact fishing gears as bottom trawling. Spatial distribution of the coral population, as well as a first attempt to characterize its habitat, are explored as an approach to describe the habitat's suitability and the vulnerability for the species in the area, Sí

En el mar profundo, allí donde la luz no llega a penetrar, el océano se hace oscuro y los ecosistemas dominados por organismos vegetales dejan paso a otros formados únicamente por animales. Entre estos ecosistemas de las zonas profundas, están los arrecifes y bosques de corales de profundidad. Como en el caso de los ecosistemas de corales tropicales, se trata de complejas estructuras tridimensionales generadas por el lento crecimiento de corales pétreos, cuyos esqueletos están formados por carbonato de calcio, así como de gorgonias y corales negros cuyos esqueletos tienen una estructura proteica. La complejidad estructural que estos organismos sésiles generan es aprovechada por multitud de especies de invertebrados y de peces que entre sus ramas encuentran refugio, alimento o el lugar idóneo de cría. Esta combinación de morfologías, colores y formas de vida da lugar a unos ecosistemas de altísima diversidad y de gran belleza. A diferencia de los corales tropicales, que se sustentan principalmente por la fotosíntesis de algas simbiontes albergadas en sus tejidos, los corales de profundidad se alimentan de las partículas y organismos que se encuentran suspendidos en el agua y que capturan gracias a los tentáculos de sus pólipos. Se trata por tanto de organismos exclusivamente heterotróficos que se alimentan de plancton y de partículas de materia orgánica. Los corales de profundidad están presentes en todos los océanos del planeta, principalmente entre 150 y 2000 m de profundidad, en aguas frías y ricas en alimento. En el Mar Mediterráneo son muchos los lugares en los que se ha observado la presencia de comunidades de corales de profundidad, especialmente en las cimas y flancos de montañas submarinas, así como en las paredes de los cañones submarinos que inciden los márgenes continentales. También se han documentado poblaciones de corales y gorgonias de profundidad en fondos rocosos de los sectores más profundos de las plataformas continentales y en sus márgenes. La elevada diversidad de especies asociada a los corales de profundidad hace de estas comunidades un enclave atractivo para la actividad pesquera. Redes y palangres de fondo pueden dañar o romper las ramas de los corales, favoreciendo así el crecimiento de organismos que los recubren y que pueden llegar a ocasionarles la muerte. Si bien la pesca de arrastre no actúa directamente en los fondos rocosos, ya que suponen un alto riesgo para el arte de pesca, el efecto que provoca su paso por los fondos sedimentarios cercanos es notable, suponiendo un importante aumento de sedimento en suspensión que puede llegar a dejar cubiertos a los corales por un fino fango del cual no pueden liberarse. A estos impactos directos hay que añadir la vulnerabilidad de estos organismos a los cambios fisicoquímicos y biológicos derivados del cambio global, especialmente los que afectan a la química de los carbonatos (acidificación), el aumento de la temperatura del agua de mar (estrés térmico) y los cambios en la circulación y la producción primaria (cambios en la disponibilidad de alimento). ​ Por todo ello, y teniendo en cuenta la elevada longevidad y el lento crecimiento de los corales de profundidad, es absolutamente necesario implementar medidas eficaces de protección de estos ecosistemas, que deben incluir la regulación de las actividades de pesca, la mejora en la selectividad de las artes de pesca para reducir su impacto, y el establecimiento de áreas marinas protegidas que incluyan las comunidades de corales de profundidad.

In September-October 2016 the oceanographic cruise MEDWAVES was conducted (in the frame of the ATLAS project H2020), in order to follow the path of the Mediterranean Outflow Water (MOW) in the Atlantic from Cádiz to the Azores. MEDWAVES aimed to investigate the influence of the MOW in the community composition of benthic assemblages in several Atlantic geomorphological features. One of the targeted areas was the Ormonde seamount in the Atlantic Ocean, 160 nautical miles SW off Cape St. Vincent, Portugal. This seamount, together with the Gettysburg seamount, is part of a volcanic ridge named Gorringe that rises from 5,000 m to less than 80m depth, respectively representing the abyssal plain until the photic zone. Its panoply of marine life and environments increased the demand for conservation measures. Consequently, Gorringe bank is currently protected by the Habitats Directive and part of Natura 2000 network since 2015. Other protective measures include the intention to designate the Gorringe Bank,as part of the seamount complex Madeira-Tore, as new Portuguese MPA of large dimensions delimited in deep oceanic areas, under the Marine Strategy Framework Directive implementation. Given its ecological importance and location through the pass of the MOW, the Ormonde seamount was selected as one of the main target areas during the MEDWAVES cruise. Six ROV dives were conducted with the Remotely Operated Vehicle (ROV) “Liropus” (IEO), covering the Northeast and North flanks of the seamount between 1,950 and 600 meters depth. As expected, the depth gradient revealed different benthic communities in the distinct depth zones. Ormonde seems to be a flourishing area for deep-sea sponges (e.g. Asconema sp.), present in high densities along with high species diversity. Scleractinian corals (e.g. Solenosmillia variabilis) as well as gorgonians (e.g. Viminella sp., Corallium tricolor) and black corals (e.g. Stichopathes sp.) were also present in the area displaying varying density patterns in the different flanks of the seamount. The depth gradient is also related with a vertical variation of the water masses, among others, the MOW, located between 500 and 1,400 m depth, with salinities from 35.6 to 36.4 and temperatures between 10 and 12°C. In this work we present the first characterization of the deep benthic megafauna communities of Ormonde and its potential relation to depth, substrate type and water masses.

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