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23 pages, 14 figures, 5 tables ; Imaging technologies are being deployed on cabled observatory networks worldwide. They allow for the monitoring of the biological activity of deep-sea organisms on temporal scales that were never attained before. In this paper, we customized Convolutional Neural Network image processing to track behavioral activities in an iconic conservation deep-sea species¿the bubblegum coral Paragorgia arborea¿in response to ambient oceanographic conditions at the Lofoten-Vesterålen observatory. Images and concomitant oceanographic data were taken hourly from February to June 2018. We considered coral activity in terms of bloated, semi-bloated and non-bloated surfaces, as proxy for polyp filtering, retraction and transient activity, respectively. A test accuracy of 90.47% was obtained. Chronobiology-oriented statistics and advanced Artificial Neural Network (ANN) multivariate regression modeling proved that a daily coral filtering rhythm occurs within one major dusk phase, being independent from tides. Polyp activity, in particular extrusion, increased from March to June, and was able to cope with an increase in chlorophyll concentration, indicating the existence of seasonality. Our study shows that it is possible to establish a model for the development of automated pipelines that are able to extract biological information from times series of images. These are helpful to obtain multidisciplinary information from cabled observatory infrastructures ; This project is funded by The Norwegian Research Council, Federal Ministry for Economic Affairs and Energy of Germany (03SX464C) and the Helmholtz Gemeinschaft Deutscher Forschungszentren (HGF) project Modular Observation Solutions for Earth Systems (MOSES), Spanish Centre for the Development of Industrial Technology (EXP 00108707/SERA-20181020), and co-funded by European Union's Horizon 2020 research and innovation program under the framework of European Research Area Network (ERA-NET) Cofund Maritime and Marine Technologies for a new Era (MarTERA)

ABSTRACT. Thriving benthic communities were observed in the oxygen minimum zones along the southwestern African margin. On the Namibian margin, fossil cold-water coral mounds were overgrown by sponges and bryozoans, while the Angolan margin was characterized by cold-water coral mounds covered by a living coral reef. To explore why benthic communities differ in both areas, present-day environmental conditions were assessed, using conductivity–temperature–depth (CTD) transects and bottom landers to investigate spatial and temporal variations of environmental properties. Near-bottom measurements recorded low dissolved oxygen concentrations on the Namibian margin of 0–0.15 mL L−1 (≜0 %–9 % saturation) and on the Angolan margin of 0.5–1.5 mL L−1 (≜7 %–18 % saturation), which were associated with relatively high temperatures (11.8–13.2 ∘C and 6.4–12.6 ∘C, respectively). Semidiurnal barotropic tides were found to interact with the margin topography producing internal waves. These tidal movements deliver water with more suitable characteristics to the benthic communities from below and above the zone of low oxygen. Concurrently, the delivery of a high quantity and quality of organic matter was observed, being an important food source for the benthic fauna. On the Namibian margin, organic matter originated directly from the surface productive zone, whereas on the Angolan margin the geochemical signature of organic matter suggested an additional mechanism of food supply. A nepheloid layer observed above the cold-water corals may constitute a reservoir of organic matter, facilitating a constant supply of food particles by tidal mixing. Our data suggest that the benthic fauna on the Namibian margin, as well as the cold-water coral communities on the Angolan margin, may compensate for unfavorable conditions of low oxygen levels and high temperatures with enhanced availability of food, while anoxic conditions on the Namibian margin are at present a limiting factor for cold-water coral growth. This study provides an example of ...

19 pages, 3 figures, 1 table, supplemental files https://doi.org/10.1525/elementa.2021.00064 ; Recent advances in robotic design, autonomy and sensor integration create solutions for the exploration of deep-sea environments, transferable to the oceans of icy moons. Marine platforms do not yet have the mission autonomy capacity of their space counterparts (e.g., the state of the art Mars Perseverance rover mission), although different levels of autonomous navigation and mapping, as well as sampling, are an extant capability. In this setting their increasingly biomimicked designs may allow access to complex environmental scenarios, with novel, highly-integrated life-detecting, oceanographic and geochemical sensor packages. Here, we lay an outlook for the upcoming advances in deep-sea robotics through synergies with space technologies within three major research areas: biomimetic structure and propulsion (including power storage and generation), artificial intelligence and cooperative networks, and life-detecting instrument design. New morphological and material designs, with miniaturized and more diffuse sensor packages, will advance robotic sensing systems. Artificial intelligence algorithms controlling navigation and communications will allow the further development of the behavioral biomimicking by cooperating networks. Solutions will have to be tested within infrastructural networks of cabled observatories, neutrino telescopes, and off-shore industry sites with agendas and modalities that are beyond the scope of our work, but could draw inspiration on the proposed examples for the operational combination of fixed and mobile platforms ; This work was developed within the framework of the Research Unit Tecnoterra (ICM-CSIC/UPC) and the following project activities: ARIM (Autonomous Robotic sea-floor Infrastructure for benthopelagic Monitoring; MarTERA ERA-Net Cofound). ARCHES (Autonomous Robotic Networks to Help Modern Societies; German Helmholtz Association). RESBIO (TEC2017-87861-R; Ministerio de Ciencia, Innovación y Universidades). JERICO-S3: (Horizon 2020; Grant Agreement no. 871153). ENDURUNS (Research Grant Agreement H2020-MG-2018-2019-2020 n.824348). We also profited from funding from the Spanish Government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2019-000928-S). A portion of this research was also carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration