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Imaging is increasingly used to capture information on the marine environment thanks to the improvements in imaging equipment, devices for carrying cameras and data storage in recent years. In that context, biologists, geologists, computer specialists and end-users must gather to discuss the methods and procedures for optimising the quality and quantity of data collected from images. The 4 Marine Imaging Workshop was organised from 3-6 October 2022 in Brest (France) in a hybrid mode. More than a hundred participants were welcomed in person and about 80 people attended the online sessions. The workshop was organised in a single plenary session of presentations followed by discussion sessions. These were based on dynamic polls and open questions that allowed recording of the imaging community’s current and future ideas. In addition, a whole day was dedicated to practical sessions on image analysis, data standardisation and communication tools. The format of this edition allowed the participation of a wider community, including lower income countries, early career scientists, all working on laboratory, benthic and pelagic imaging. This article summarises the topics addressed during the workshop, particularly the outcomes of the discussion sessions for future reference and to make the workshop results available to the open public.

The ChEReef 2022 cruise contributes to the European projects Marha and iAtlantic and the ANR project ARDECO. Its overall objective is to better understand the role of geomorphological, hydrodynamic, sedimentary and anthropic factors in the distribution and health of reef habitats in a canyon of the Bay of Biscay, by answering four main questions: 1. What is the role of the heterogeneity of the geomorphological structures of a canyon in the distribution and diversity of benthic habitats? 2. How does a canyon influence local hydrodynamics and what are the consequences for the nature, distribution and dynamics of benthic habitats? 3. What are the nature, quantities and dynamics of sedimentary and trophic inputs in a canyon? 4. What are the main natural and anthropogenic drivers of the realized niche of reef-buidlinging coral species? To tackle these questions, the cruise includes : - ROV Victor dives dedicated to annual maintenance of the MARLEY benthic observation platform; - ROV Victor dives dedicated to sampling reef-building coral colonies, their associated fauna, substrates and surrounding water, in order to characterize biodiversity and assess the physiological state of corals, including their microbiome; - ROV Victor dives dedicated to photo and video acquisition, including with a hyperspectral camera, to map coral habitats, measure their extent and assess their state of health; - ROV Victor dives dedicated to the deployment of experimental devices to assess growth rates, larval recruitment and colonization rates; - ROV Victor dives dedicated to canyon exploration, to continue mapping benthic habitats within the canyon; - Grab coring to characterize sedimentary facies in the canyon; - Zooplankton sampling in the water column to sample larvae of benthic organisms; - Recovery of three mooring lines, each equipped with a particle trap, an ADCP and a turbidimeter, then redeployment of two of them, in order to characterize currents and particle flows in the canyon, La campagne ChEReef 2022 contribue aux projets européens Marha et iAtlantic et au projet ANR ARDECO. L’objectif est de mieux comprendre le rôle des facteurs géomorphologiques, hydrodynamiques, sédimentaires et anthropiques dans la distribution des habitats récifs d’un canyon du golfe de Gascogne, en répondant à quatre grandes questions : - Quel est le rôle de l’hétérogénéité des structures géomorphologiques d’un canyon dans la distribution et la diversité des habitats benthiques ? - Comment un canyon influence-t’il l’hydrodynamisme local et quelles en sont les conséquences sur la nature, la distribution et la dynamique des habitats benthiques ? - Quelles sont la nature, les quantités et la dynamique des apports sédimentaires et trophiques dans un canyon ? - Quels sont les taux de croissance et les conditions optimales de croissance des espèces de coraux récifaux ? Pour répondre à ces questions, le programme de la campagne inclue: - Des plongées du ROV Victor dédiées à la maintenance annuelle de la plateforme d’observations benthiques MARLEY ; - Des plongées du ROV Victor dédiées à l’échantillonnage des colonies de coraux récifaux, leurs faunes associées, les substrats et l’eau environnante, afin de caractériser la biodiversité et d’évaluer l’état physiologique des coraux récifaux, y compris leur microbiome ; - Des plongées du ROV Victor dédiées à l’acquisition de photos et de vidéos, y compris avec une caméra hyperspectrale afin de cartographier les habitats coralliens, mesurer leur étendue et évaluer leur état de santé ; - Des plongées du ROV Victor dédiées au déploiement de dispositifs expérimentaux afin d’évaluer les taux de croissance, de recrutement larvaire et de colonisation des coraux récifaux ; - Des plongées du ROV Victor dédiées à l’exploration du canyon afin de poursuivre la cartographie des habitats benthiques du canyon ; - Des carottages bennes afin de caractériser les faciès sédimentaires dans le canyon ; - Des profils de mesures et de prélèvements d

EMB Future Science Brief No. 11 ‘Marine habitat mapping’ presents science and policy needs and recommendations to advance next-generation marine habitat mapping. It highlights current methods and future trends in the acquisition of data from the seabed and water column via remote sensing and direct, in situ techniques. It discusses combining data to produce maps using modelling approaches and presents recommendations for adopting fit-for-purpose habitat classification schemes. It also provides an overview of what has been mapped and where within the European sea-basins, highlights the need to increase the quality and resolution of marine habitat maps. It identifies critical gaps in habitat types and geographic extent, including the coastal areas, the deep sea, Natura 2000 sites and other Marine Protected Areas across all regional seas. Finally, it describes the need to improve the assessment and communication of uncertainty and confidence in maps, and to make maps more easily accessible to a variety of stakeholders to increase their value for end-users and to the public for Ocean literacy.

The Habitats Directive (92/43/CEE) is one of the political pillars of the European Union in terms of marine biodiversity. Under the directive, each Member State must report periodically the conservation status and evolution trends of species and habitats of Community interest. This conservation status of habitats is characterised by four parameters: habitat range, habitat area, habitat structure and functions, and future prospects according to the pressures acting on the habitat and the management measures put in place. In previous reports, the assessment of the 1170-Reefs habitat considered only partially the geological and biogenic reefs of the deep sea (bathyal). To overcome such a knowledge gap, a scientific review was carried out according to the four evaluation parameters in order to advance an overall assessment of the bathyal Reefs for the French Atlantic and Mediterranean marine biogeographical regions. The overall assessment of the conservation status of bathyal Reefs is « unfavourableinadequate » in the Atlantic and « unfavourable-bad » in the Mediterranean. Although management measures are in place or planned, they are not sufficient to ensure a favourable conservation status for the bathyal Reefs in the long term., La Directive Habitats-Faune-Flore (92/43/CEE) est un des piliers de la politique de l’Union européenne en faveur de la biodiversité marine. Cette directive impose aux États membres de rapporter périodiquement l’état de conservation et les tendances d’évolution des espèces et habitats d’intérêt communautaire. Pour les habitats, quatre paramètres sont considérés : l’aire de répartition, la surface occupée par l’habitat, l’état de la structure et des fonctions de l’habitat, et les perspectives futures selon les pressions agissant sur l’habitat et selon les mesures de gestion mises en place. Les précédents rapportages pour l’habitat 1170 – Récifs n’ont considéré que partiellement les récifs géologiques et biogènes de l’environnement profond (bathyal). Pour pallier cette lacune, un bilan des connaissances a été réalisé selon les quatre paramètres d’évaluation afin de proposer une évaluation globale de l’habitat Récifs bathyal pour les régions biogéographiques marines Atlantique et Méditerranée françaises. Les évaluations globales de l’état de conservations des Récifs du bathyal indiquent un état de conservation « défavorable-inadéquat » en Atlantique et « défavorable-mauvais » en Méditerranée. Même si des mesures de gestions sont en place ou sont à venir, elles restent insuffisantes pour assurer à long terme un état de conservation favorable de l’habitat Récifs de la zone bathyale.

Dans le contexte de la Directive Habitats, Faune, Flore, le projet européen Life Intégré Marha a pour objectif d'évaluer et d'améliorer l’état de conservation des habitats naturels marins. L'Ifremer, bénéficiaire associé à ce projet, a développé le projet ChEReef qui s'attelle à l'évaluation de l'état de santé des coraux profonds dans le canyon sous-marin de Lampaul (Golfe de Gascogne). La méthodologie développée pour les habitats de coraux profonds cherche à répondre au double objectif d’évaluation du bon état de conservation (Directive Habitat Faune Flore) et d’évaluation du bon état écologique (Directive Cadre Stratégie pour le Milieu Marin). Les deux directives partagent des points communs dans leurs critères et leurs démarches. En particulier, les évaluations cherchent à caractériser le couple état‐pression suivant trois approches : 1. Décrire et cartographier les habitats, 2. Caractériser et cartographier les pressions, 3. Etablir les conséquences des pressions sur les structures et fonctions des habitats. Les deux premières approches s’appuient sur un suivi surfacique, tandis que la troisième requiert un suivi stationnel. Ce suivi stationnel répond au besoin d’acquérir des données sur la biologie des espèces structurantes, la diversité des espèces accompagnatrices, et les processus écologiques forçant la dynamique des espèces et habitats. Les cycles d’évaluation de la DHFF et de la DCSMM ont une période de 6 ans. En environnement profond cependant, la périodicité, l’amplitude et les causes de variations naturelles des populations et des communautés sont très peu contraintes. Il est donc important de caractériser et comprendre les dynamiques naturelles des habitats profonds à différentes échelles spatio‐temporelles afin d’élaborer des indicateurs et proposer des seuils de bon état de conservation et de bon état écologique. C’est une des finalités des six campagnes océanographiques hauturières ChEReef obtenues auprès de la Flotte océanographique Française. Ces

Dans le contexte de la Directive Habitats, Faune, Flore, le projet européen Life Intégré Marha a pour objectif d'évaluer et d'améliorer l’état de conservation des habitats naturels marins. L'Ifremer, bénéficiaire associé à ce projet, a développé le projet ChEReef qui s'attelle à l'évaluation de l'état de santé des coraux profonds dans le canyon sous-marin de Lampaul (Golfe de Gascogne). La méthodologie développée pour les habitats de coraux profonds cherche à répondre au double objectif d’évaluation du bon état de conservation (Directive Habitat Faune Flore) et d’évaluation du bon état écologique (Directive Cadre Stratégie pour le Milieu Marin). Les deux directives partagent des points communs dans leurs critères et leurs démarches. En particulier, les évaluations cherchent à caractériser le couple état‐pression suivant trois approches : 1. Décrire et cartographier les habitats, 2. Caractériser et cartographier les pressions, 3. Etablir les conséquences des pressions sur les structures et fonctions des habitats. Les deux premières approches s’appuient sur un suivi surfacique, tandis que la troisième requiert un suivi stationnel. Ce suivi stationnel répond au besoin d’acquérir des données sur la biologie des espèces structurantes, la diversité des espèces accompagnatrices, et les processus écologiques forçant la dynamique des espèces et habitats. Les cycles d’évaluation de la DHFF et de la DCSMM ont une période de 6 ans. En environnement profond cependant, la périodicité, l’amplitude et les causes de variations naturelles des populations et des communautés sont très peu contraintes. Il est donc important de caractériser et comprendre les dynamiques naturelles des habitats profonds à différentes échelles spatio‐temporelles afin d’élaborer des indicateurs et proposer des seuils de bon état de conservation et de bon état écologique. C’est une des finalités des six campagnes océanographiques hauturières ChEReef obtenues auprès de la Flotte océanographique Française. Ces

Hybrid conferences are in-person events that have an online component. This type of meeting format was rare before the COVID-19 pandemic, but started to become more common recently given the asynchronous global progression of the pandemic, the uneven access to vaccines and different travel regulations among countries that led to a large proportion of participants being unable to attend conferences in person. Here we report the organization of a middle-sized (581 participants: 159 onsite, 422 online) international hybrid conference that took place in France in September 2021. We highlight particular organizational challenges inherent to this relatively new type of meeting format. Furthermore, we surveyed both in-person and online participants to better understand their conference experience and to propose improvements based on the feedback received. Finally, we compare the advantages and disadvantages of three types of conferences (onsite-only, online-only and hybrid) and suggest that hybrid events should be favored in the future because they offer the most flexibility to participants. We conclude by proposing suggestions and ways forward to maximize accessibility and inclusivity of hybrid conferences. Our study brings novel insights on the challenges and opportunities created by hybrid conferences, by reporting not only the organizing committee experience but also by considering the participants’ perspective.

Vulnerable marine ecosystems (VMEs) are particularly susceptible to bottom-fishing activity as they are easily disturbed and slow to recover. A data-driven approach was developed to provide management options for the protection of VMEs under the European Union “deep-sea access regulations.” A total of two options within two scenarios were developed. The first scenario defined VME closure areas without consideration of fishing activity. Option 1 proposed closures for the protection of VME habitats and likely habitat, while Option 2 also included areas where four types of VME geophysical elements were present. The second scenario additionally considered fishing. This scenario used VME biomass—fishing intensity relationships to identify a threshold where effort of mobile bottom-contact gears was low and unlikely to have caused significant adverse impacts. Achieving a high level of VME protection requires the creation of many closures (> 100), made up of many small (∼50 km2) and fewer larger closures (> 1000 km2). The greatest protection of VMEs will affect approximately 9% of the mobile fleet fishing effort, while closure scenarios that avoid highly fished areas reduce this to around 4–6%. The framework allows managers to choose the level of risk-aversion they wish to apply in protecting VMEs by comparing alternative strategies.

Océanopolis, centre de Culture Scientifique et Technique localisé à Brest, dédie un espace d’exposition aux environments profonds (https://www.oceanopolis.com/). En particulier, il sera partie prenante de la thématique “mediation scientifique” du projet ANR ARDECO (Assessing Resilience of DEep COrals ) du laboratoire Ifremer EP. A ce titre il prévoit de realiser des activités autours des coraux d’eaux froides, dont la projection de sequences vidéos enregistrées par les robots sous-marins dans différents canyons, aussi bien atlantiques que méditerranéens. Pour répondre à ce besoin, des séquences vidéo des campagnes VIDEOCOR_2017 et CALADU_2021 sont mises à disposition.

The increasing demand for metals is pushing forward the progress of deep-sea mining industry. The abyss between the Clarion and Clipperton Fracture Zones (CCFZ), a region holding a higher concentration of minerals than land deposits, is the most targeted area for the exploration of polymetallic nodules worldwide, which may likely disturb the seafloor across large areas and over many years. Effects from nodule extraction cause acute biodiversity loss of organisms inhabiting sediments and polymetallic nodules. Attention to deep-sea ecosystems and their services has to be considered before mining starts but the lack of basic scientific knowledge on the methodologies for the ecological surveys of fauna in the context of deep-sea mining impacts is still scarce. We review the methodology to sample, process and investigate metazoan infauna both inhabiting sediments and nodules dwelling on these polymetallic-nodule areas. We suggest effective procedures for sampling designs, devices and methods involving gear types, sediment processing, morphological and genetic identification including metabarcoding and proteomic fingerprinting, the assessment of biomass, functional traits, fatty acids, and stable isotope studies within the CCFZ based on both first-hand experiences and literature. We recommend multi- and boxcorers for the quantitative assessments of meio- and macrofauna, respectively. The assessment of biodiversity at species level should be focused and/or the combination of morphological with metabarcoding or proteomic fingerprinting techniques. We highlight that biomass, functional traits, and trophic markers may provide critical insights for biodiversity assessments and how statistical modeling facilitates predicting patterns spatially across point-source data and is essential for conservation management.

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

Macrofauna are an abundant and diverse component of abyssal benthic communities and are likely to be heavily impacted by polymetallic nodule mining in the Clarion-Clipperton Zone (CCZ). In 2012, the International Seabed Authority (ISA) used available benthic biodiversity data and environmental proxies to establish nine no-mining areas, called Areas of Particular Environmental Interest (APEIs) in the CCZ. The APEIs were intended as a representative system of protected areas to safeguard biodiversity and ecosystem function across the region from mining impacts. Since 2012, a number of research programs have collected additional ecological baseline data from the CCZ. We assemble and analyze macrofaunal biodiversity data sets from eight studies, focusing on three dominant taxa (Polychaeta, Tanaidacea, and Isopoda), and encompassing 477 box-core samples to address the following questions: (1) How do macrofaunal abundance, biodiversity, and community structure vary across the CCZ, and what are the potential ecological drivers? (2) How representative are APEIs of the nearest contractor areas? (3) How broadly do macrofaunal species range across the CCZ region? and (4) What scientific gaps hinder our understanding of macrofaunal biodiversity and biogeography in the CCZ? Our analyses led us to hypothesize that sampling efficiencies vary across macrofaunal data sets from the CCZ, making quantitative comparisons between studies challenging. Nonetheless, we found that macrofaunal abundance and diversity varied substantially across the CCZ, likely due in part to variations in particulate organic carbon (POC) flux and nodule abundance. Most macrofaunal species were collected only as singletons or doubletons, with additional species still accumulating rapidly at all sites, and with most collected species appearing to be new to science. Thus, macrofaunal diversity remains poorly sampled and described across the CCZ, especially within APEIs, where a total of nine box cores have been

Dans le cadre de la mise en œuvre de la Directive Cadre sur le Milieu Marin (DCSMM), l’un des objectifs environnementaux est d’éviter l’abrasion et l’étouffement des zones les plus représentatives des habitats profonds (Ecosystèmes Marins Vulnérables, EMV). Pour la façade méditerranéenne, la fiche d’opérationnalisation de cet objectif (D01-HB-OE10) définie les EMV comme incluant le Corail Bambou (Isidella elongata), les coraux froids, les fonds à crinoïdes (Leptometra phalangium) et les fonds à pennatulaires (Funiculina quadrangularis) au-delà de 200 m de profondeur ou au-delà de 60m de profondeur dans le cas particulier du plateau oriental corse. L’Ifremer en tant que contributeur technique est chargé d’agréger les données existantes sur les occurrences des espèces indicatrices. La présente note liste les sources de données et décrit la méthode d’agrégation ayant conduit à la réalisation des cartes de distribution des Ecosystèmes Marins Vulnérables de Méditerranée.

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Howell, K. L., Hilario, A., Allcock, A. L., Bailey, D. M., Baker, M., Clark, M. R., Colaco, A., Copley, J., Cordes, E. E., Danovaro, R., Dissanayake, A., Escobar, E., Esquete, P., Gallagher, A. J., Gates, A. R., Gaudron, S. M., German, C. R., Gjerde, K. M., Higgs, N. D., Le Bris, N., Levin, L. A., Manea, E., McClain, C., Menot, L., Mestre, N. C., Metaxas, A., Milligan, R. J., Muthumbi, A. W. N., Narayanaswamy, B. E., Ramalho, S. P., Ramirez-Llodra, E., Robson, L. M., Rogers, A. D., Sellanes, J., Sigwart, J. D., Sink, K., Snelgrove, P. V. R., Stefanoudis, P., V., Sumida, P. Y., Taylor, M. L., Thurber, A. R., Vieira, R. P., Watanabe, H. K., Woodall, L. C., & Xavier, J. R. A blueprint for an inclusive, global deep-sea ocean decade field program. Frontiers in Marine Science, 7, (2020): 584861, doi:10.3389/fmars.2020.584861., The ocean plays a crucial role in the functioning of the Earth System and in the provision of vital goods and services. The United Nations (UN) declared 2021–2030 as the UN Decade of Ocean Science for Sustainable Development. The Roadmap for the Ocean Decade aims to achieve six critical societal outcomes (SOs) by 2030, through the pursuit of four objectives (Os). It specifically recognizes the scarcity of biological data for deep-sea biomes, and challenges the global scientific community to conduct research to advance understanding of deep-sea ecosystems to inform sustainable management. In this paper, we map four key scientific questions identified by the academic community to the Ocean Decade SOs: (i) What is the diversity of life in the deep ocean? (ii) How are populations and habitats connected? (iii) What is the role of living organisms in ecosystem function and service provision? and (iv) How do species, communities, and ecosystems respond to disturbance? We then consider the design of a global-scale program to address these questions by reviewing key drivers of ecological pattern and process. We recommend using the following criteria to stratify a global survey design: biogeographic region, depth, horizontal distance, substrate type, high and low climate hazard, fished/unfished, near/far from sources of pollution, licensed/protected from industry activities. We consider both spatial and temporal surveys, and emphasize new biological data collection that prioritizes southern and polar latitudes, deeper (> 2000 m) depths, and midwater environments. We provide guidance on observational, experimental, and monitoring needs for different benthic and pelagic ecosystems. We then review recent efforts to standardize biological data and specimen collection and archiving, making “sampling design to knowledge application” recommendations in the context of a new global program. We also review and comment on needs, and recommend actions, to develop capacity in deep-sea res, Development of this paper was supported by funding from the Scientific Committee on Oceanic Research (SCOR) awarded to KH and AH as working group 159 co-chairs. KH, BN, and KS are supported by the UKRI funded One Ocean Hub NE/S008950/1. AH work is supported by the CESAM (UIDP/50017/2020 + 1432 UIDB/50017/2020) that is funded by Fundação para a Ciência e a Tecnologia (FCT)/MCTES through national funds. AA is supported by Science Foundation Ireland and the Marine Institute under the Investigators Program Grant Number SFI/15/IA/3100 co-funded under the European Regional Development Fund 2014–2020. AC is supported through the FunAzores -ACORES 01-0145-FEDER-000123 grant and by FCT through strategic project UID/05634/2020 and FCT and Direção-Geral de Politica do Mar (DGPM) through the project Mining2/2017/005. PE is funded by national funds (OE), through FCT in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. SG research is supported by CNRS funds. CG is supported by an Independent Study Award and the Investment in Science Fund at WHOI. KG gratefully acknowledges support from Synchronicity Earth. LL is funded by the NOAA Office of Ocean Exploration and Research (NA19OAR0110305) and the US National Science Foundation (OCE 1634172). NM is supported by FCT and DGPM, through the project Mining2/2017/001 and the FCT grants CEECIND/00526/2017, UIDB/00350/2020 + UIDP/00350/2020. SR is funded by the FCTgrant CEECIND/00758/2017. JS is supported by ANID FONDECYT #1181153 and ANID Millennium Science Initiative Program #NC120030. JX research is funded by the European Union’s Horizon 2020 research and innovation program through the SponGES project (grant agreement no. 679849) and further supported by national funds through FCT within the scope of UIDB/04423/2020 and UIDP/04423/2020. The Natural Sciences and Engineering Council of Canada supports AM and PVRS. MB and th

The deep sea is the largest biome on Earth but the least explored. Our knowledge of it comes from scattered sources spanning different spatial and temporal scales. Implementation of marine policies like the European Union’s Marine Strategy Framework Directive (MSFD) and support for Blue Growth in the deep sea are therefore hindered by lack of data. Integrated assessments of environmental status require tools to work with different and disaggregated datasets (e.g. density of deep-sea habitat-forming species, body-size distribution of commercial fishes, intensity of bottom trawling) across spatial and temporal scales. A feasibility study was conducted as part of the four-year ATLAS project to assess the effectiveness of the open-access Nested Environmental status Assessment Tool (NEAT) to assess deep-sea environmental status. We worked at nine selected study areas in the North Atlantic focusing on five MSFD descriptors (D1-Biodiversity, D3-Commercial fish and shellfish, D4-Food webs, D6-Seafloor integrity, D10-Marine litter). The objectives of the present study were to i) explore and propose indicators that could be used in the assessment of deep-sea environmental status, ii) evaluate the performance of NEAT in the deep sea, and iii) identify challenges and opportunities for the assessment of deep-sea status. Based on data availability, data quality and expert judgement, in total 24 indicators (one for D1, one for D3, seven for D4, 13 for D6, two for D10) were used in the assessment of the nine study areas, their habitats and ecosystem components. NEAT analyses revealed differences among the study areas for their environmental status ranging from “poor” to “high”. Overall, the NEAT results were in moderate to complete agreement with expert judgement, previous assessments, scientific literature on human-pressure gradients and expected management outcomes. We suggest that the assessment of deep-sea environmental status should take place at habitat and ecosystem level (r

The deep sea plays a critical role in global climate regulation through uptake and storage of heat and carbon dioxide. However, this regulating service causes warming, acidification and deoxygenation of deep waters, leading to decreased food availability at the seafloor. These changes and their projections are likely to affect productivity, biodiversity and distributions of deep‐sea fauna, thereby compromising key ecosystem services. Understanding how climate change can lead to shifts in deep‐sea species distributions is critically important in developing management measures. We used environmental niche modelling along with the best available species occurrence data and environmental parameters to model habitat suitability for key cold‐water coral and commercially important deep‐sea fish species under present‐day (1951–2000) environmental conditions and to project changes under severe, high emissions future (2081–2100) climate projections (RCP8.5 scenario) for the North Atlantic Ocean. Our models projected a decrease of 28%–100% in suitable habitat for cold‐water corals and a shift in suitable habitat for deep‐sea fishes of 2.0°–9.9° towards higher latitudes. The largest reductions in suitable habitat were projected for the scleractinian coral Lophelia pertusa and the octocoral Paragorgia arborea, with declines of at least 79% and 99% respectively. We projected the expansion of suitable habitat by 2100 only for the fishes Helicolenus dactylopterus and Sebastes mentella (20%–30%), mostly through northern latitudinal range expansion. Our results projected limited climate refugia locations in the North Atlantic by 2100 for scleractinian corals (30%–42% of present‐day suitable habitat), even smaller refugia locations for the octocorals Acanella arbuscula and Acanthogorgia armata (6%–14%), and almost no refugia for P. arborea. Our results emphasize the need to understand how anticipated climate change will affect the distribution of deep‐sea species including commerciall

In the abyssal Equatorial Pacific Ocean, most of the seafloor of the Clarion-Clipperton Fracture Zone (CCFZ), a 6 million km2 polymetallic nodule province, has been preempted for future mining. In light of the large footprint that mining would leave, and given the diversity and the vulnerability of the abyssal fauna, the International Seabed Authority has implemented a regional management plan that includes the creation of nine areas of particular environmental interest (APEIs) located at the periphery of the CCFZ. The APEIs were defined based on the best – albeit very limited – scientific knowledge for the area. The fauna and habitats in the APEIs are unknown, as are species' ranges and the extent of biodiversity across the CCFZ. As part of the Joint Programming Initiative Healthy and Productive Seas and Oceans (JPI Oceans) pilot action Ecological aspects of deep-sea mining, the SO239 cruise aimed at improving species inventories, determining species ranges, identifying the drivers of beta diversity patterns and assessing the representativeness of an APEI. Four exploration contract areas and an APEI (APEI#3) were sampled along a gradient of sea-surface primary productivity that spanned a distance of 1440 km in the eastern CCFZ. Between 3 and 8 quantitative box cores (0.25 m2; 0–10 cm) were sampled in each study area, resulting in a large collection of polychaetes that were morphologically and molecularly (COI and 16S genes) analyzed. A total of 275 polychaete morphotypes were identified. Only one morphotype was shared among all five study areas and 49 % were singletons. The patterns in community structure and composition were mainly attributed to variations in food fluxes at the regional scale and nodule density at the local scale. The four exploration contract areas belong to a mesotrophic province. The distance-decay of similarity among the four areas provides an estimated species turnover of 0.04 species km−1 and an average species range of 25 km. The polychaete