18 results on '"Chatzievangelou, D."'
Search Results
2. New high-tech flexible networks for the monitoring of deep-sea ecosystems
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Aguzzi, J., Chatzievangelou, D., Marini, S., Fanelli, E., Danovaro, R., Flogel, S., Juanes, F., De Leo, F., Del Rio, J., Laurenz, T., Costa, C., Riccobene, G., Tamburini, C., Lefevre, D., Gojak, C., Poulain, P-M., Favali, P., Griffa, A., Purser, A., Cline, D., Edgington, D., Navarro, J., Stefanini, S., Hondt, S. D, Priede, I. G., Rountree, R., and Company, J. B.
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Physics - Instrumentation and Detectors ,Quantitative Biology - Populations and Evolution - Abstract
Increasing interest in the acquisition of biotic and abiotic resources from within the deep sea (e.g. fisheries, oil-gas extraction, and mining) urgently imposes the development of novel monitoring technologies, beyond the traditional vessel-assisted, time-consuming, high-cost sampling surveys. The implementation of permanent networks of seabed and water-column cabled (fixed) and docked mobile platforms is presently enforced, to cooperatively measure biological features and environmental (physico-chemical) parameters. Video and acoustic (i.e. optoacoustic) imaging are becoming central approaches for studying benthic fauna (e.g. quantifying species presence, behaviour, and trophic interactions) in a remote, continuous, and prolonged fashion. Imaging is also being complemented by in situ environmental-DNA sequencing technologies, allowing the traceability of a wide range of organisms (including prokaryotes) beyond the reach of optoacoustic tools. Here, we describe the different fixed and mobile platforms of those benthic and pelagic monitoring networks, proposing at the same time an innovative roadmap for the automated computing of hierarchical ecological information of deep-sea ecosystems (i.e. from single species abundance and life traits, to community composition, and overall biodiversity), Comment: 56 pages, 4 figures This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Environmental Science and Technology, copyright American Chemical Society after peer review. To access the final edited and published work see Journal Reference
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- 2022
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3. Working Group on Nephrops Surveys (WGNEPS; outputs from 2022 meeting)
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Aguzzi J., Aristegui-Ezquibela M., Burgos C., Chatzievangelou D., Doyle J., Fallon N., Fifas S., González-Herraiz I., Jonsson P., Lundy M., Martinelli M., Medve?ek D., Naseer A., Nava E., Nawri N., Jónasson J. P., Pereira B., Pieri G., Silva C., Tibone M., Valeiras J., Vila Y., Weetman A., and Wieland K.
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Fisheries and aquaculture ,Technologies and data ,Adriatic Sea (ICES adjacent region) ,UWTV ,Nephrops ,Ecosystem observation, processes and dynamics ,Survey ,All ICES Ecoregions - Abstract
The Working Group on Nephrops Surveys (WGNEPS) is the international coordination group for Nephrops underwater television and trawl surveys within ICES. This report summarizes the national contributions on the results of the surveys conducted in 2022 together with time series covering all survey years, problems encountered, data quality checks and technological improvements as well as the planning for survey activities for 2023. In total, 21 surveys covering 26 functional units (FU’s) in the ICES area and 1 geographical subarea (GSA) in the Adriatic Sea were discussed and further improvements in respect to survey design and data analysis standardization and the use of most recent technology were reviewed. The first exploratory UWTV survey on the FU 25 Nephrops grounds was also presented to the group. The results of the evaluation of reference sets for FU3&4 Skagerrak/Kattegat were accepted following the process set down by the 2018 workshop (WKNEPS). An alternative method estimate Nephrops abundance was shown to the group using the recently published R package sdmTMB. The group agreed to hold a workshop in 2025 to address burrow size estimations to update correction factors and terms of reference for this to be agreed at next meeting. Automatic burrow detection based on deep learning methods continues to show promising results where datasets from multiple institutes were used. Plans are being progressed for an international Nephrops UWTV database to be established at the ICES data centre with a sub-group.
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- 2023
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4. Advancing fishery-independent stock assessments for the Norway lobster (Nephrops norvegicus) with new monitoring techn
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Aguzzi, J., Chatzievangelou, D., Robinson, N.J., Bahamon, N., Berry, A., Carreras, M., Company, J.B., Costa, C., del Rio Fernandez, J., Falahzadeh, A., Fifas, S., Flögel, S., Grinyó, J., Jónasson, J.P., Lordan, C., Lundy, M., Marini, S., Martinelli, M., Masmitja, I., Mirimin, L., Naseer, A., Navarro, J., Palomeras, N., Picardi, G., Silva, C., Stefanni, S., Vigo, M., Vila, Yolanda, Weetman, A., Doyle, J., Aguzzi, J., Chatzievangelou, D., Robinson, N.J., Bahamon, N., Berry, A., Carreras, M., Company, J.B., Costa, C., del Rio Fernandez, J., Falahzadeh, A., Fifas, S., Flögel, S., Grinyó, J., Jónasson, J.P., Lordan, C., Lundy, M., Marini, S., Martinelli, M., Masmitja, I., Mirimin, L., Naseer, A., Navarro, J., Palomeras, N., Picardi, G., Silva, C., Stefanni, S., Vigo, M., Vila, Yolanda, Weetman, A., and Doyle, J.
- Abstract
The Norway lobster, Nephrops norvegicus, supports a key European fishery. Stock assessments for this species are mostly based on trawling and UnderWater TeleVision (UWTV) surveys. However, N. norvegicus are burrowing organisms and these survey methods are unable to sample or observe individuals in their burrows. To account for this, UWTV surveys generally assume that “1 burrow system = 1 animal”, due to the territorial behavior of N. norvegicus. Nevertheless, this assumption still requires in-situ validation. Here, we outline how to improve the accuracy of current stock assessments for N. norvegicus with novel ecological monitoring technologies, including: robotic fixed and mobile camera-platforms, telemetry, environmental DNA (eDNA), and Artificial Intelligence (AI). First, we outline the present status and threat for overexploitation in N. norvegicus stocks. Then, we discuss how the burrowing behavior of N. norvegicus biases current stock assessment methods. We propose that state-of-the-art stationary and mobile robotic platforms endowed with innovative sensors and complemented with AI tools could be used to count both animals and burrows systems in-situ, as well as to provide key insights into burrowing behavior. Next, we illustrate how multiparametric monitoring can be incorporated into assessments of physiology and burrowing behavior. Finally, we develop a flowchart for the appropriate treatment of multiparametric biological and environmental data required to improve current stock assessment methods.
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- 2022
5. The potential of video imagery from worldwide cabled observatory networks to provide information supporting fish-stock and biodiversity assessment
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Aguzzi, J, primary, Chatzievangelou, D, additional, Company, J B, additional, Thomsen, L, additional, Marini, S, additional, Bonofiglio, F, additional, Juanes, F, additional, Rountree, R, additional, Berry, A, additional, Chumbinho, R, additional, Lordan, C, additional, Doyle, J, additional, del Rio, J, additional, Navarro, J, additional, De Leo, F C, additional, Bahamon, N, additional, García, J A, additional, Danovaro, P R, additional, Francescangeli, M, additional, Lopez-Vazquez, V, additional, and Gaughan, P, additional
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- 2020
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6. Ocean Observatories as a Tool to Advance Gas Hydrate Research
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Scherwath, M., primary, Thomsen, L., additional, Riedel, M., additional, Römer, M., additional, Chatzievangelou, D., additional, Schwendner, J., additional, Duda, A., additional, and Heesemann, M., additional
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- 2019
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7. Quality control and pre-analysis treatment of 5-year long environmental datasets collected by an Internet Operated Deep-sea Crawler
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Chatzievangelou, D., Jacopo Aguzzi, Thomsen, L., Ocean Networks Canada, Neptune Canada, Helmholtz Association, European Commission, and Ministerio de Ciencia, Innovación y Universidades (España)
- Abstract
2019 IMEKO TC-19 International Workshop on Metrology for the Sea (MetroSea 2019), 3-5 October 2019, Genova, Italy.-- 5 pages, 5 figures, 1 table, As technological advances nowadays allow for long-term, high-frequency deep-sea monitoring studies, the collected datasets are increasing in size and diversity. As a consequence, together with the need for larger-scale management, the issue of the standardization of data collection and treatment and the comparability between datasets of distinct sources is being raised. This study presents examples of data treatment steps followed, in order to ensure that the datasets collected during a period of 5 years by the Internet Operated Deep-sea Crawler “Wally> meet high quality standards and are adequate for the production of reliable results to monitor of the Barkley Canyon methane hydrates site, off Vancouver Island (BC, Canada). In addition to internationally established automated procedures, different standardizing, normalizing and detrending methods can be used on a case-by-case basis, depending on the nature of the treated oceanographic variable and the range and scale of the values provided by each different sensor, The development and deployment of the crawler, as well as individual studies were funded by Ocean Networks Canada and Neptune Canada (http://www.oceannetworks.ca/), the Robotic Exploration of Extreme Environments (ROBEX) project of the Helmholtz Alliance (HA-304; http://www.helmholtz.de/), the EU ESONET program (contract no. 036851), the Tecnoterra Joint Unit (ICM-CSIC/UPC) and RESNEP project (CTM2017-82991-C2-1-R) of the Spanish national RTD program
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- 2019
8. Ocean Observatories as a Tool to Advance Gas Hydrate Research
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Scherwath, M., Thomsen, L., Riedel, Michael, Römer, M., Chatzievangelou, D., Schwendner, J., Duda, A., Heesemann, M., Scherwath, M., Thomsen, L., Riedel, Michael, Römer, M., Chatzievangelou, D., Schwendner, J., Duda, A., and Heesemann, M.
- Abstract
Since 2009, unprecedented comprehensive long-term gas hydrate observations have become available from Ocean Networks Canada's NEPTUNE cabled ocean observatory at the northern Cascadia margin. Several experiments demonstrate the scientific importance of permanent power and Internet connectivity to the ocean floor as they have advanced the field of gas hydrate related research. One example is the cabled crawler Wally at Barkley Canyon, enabling live in situ exploration of the hydrate mounds and its associated benthic communities through the crawler's mobility and permanent accessibility throughout the year. Another example is a bubble-imaging sonar at Clayoquot Slope, revealing the strong relationship between ebullition of natural gas and tidal pressure, without apparent correlation to earthquakes, storms, or temperature fluctuations, in year-long continuous recordings. Finally, regular observatory maintenance cruises allow additional science sampling including echo-sounder surveys to extend the observatory footprint. Long-term trends in the data are not yet apparent but can also become evident from continuous measurements, as ocean observatories such as NEPTUNE are built for a 25-year lifetime, and expansion of the observatory networks makes these findings comparable and testable. Plain Language Summary Natural gas near the ocean floor creates a rapidly changing environment where it is important to collect data continuously in order to determine the magnitude, speed, and potential mechanism of change. This long-standing challenge of year-round access to the deep ocean has been tackled by Ocean Networks Canada through cabling the northern Cascadia seafloor, providing power and Internet communication-ideal for power-hungry instruments, large data volumes, and real-time access. The presence of gas influences the shape of the seafloor, animal activity, and potential escape of methane, a potent greenhouse gas. A seafloor crawler Wally was operated around deep canyon mound
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- 2019
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9. The potential of video imagery from worldwide cabled observatory networks to provide information supporting fish-stock and biodiversity assessment.
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Aguzz, J., Chatzievangelou, D., Company, J. B., Thomsen, L., Marini, S., Bonofiglio, F., Juanes, F., Rountree, R., Berry, A., Chumbinho, R., Lordan, C., Doyle, J., del Rio, J., Navarro, J., De Leo, F. C., Bahamon, N., García, J. A., Danovaro, P. R., Francescangeli, M., and Lopez-Vazquez, V.
- Abstract
Seafloor multiparametric fibre-optic-cabled video observatories are emerging tools for standardized monitoring programmes, dedicated to the production of real-time fishery-independent stock assessment data. Here, we propose that a network of cabled cameras can be set up and optimized to ensure representative long-term monitoring of target commercial species and their surrounding habitats. We highlight the importance of adding the spatial dimension to fixed-point-cabled monitoring networks, and the need for close integration with Artificial Intelligence pipelines, that are necessary for fast and reliable biological data processing. We then describe two pilot studies, exemplary of using video imagery and environmental monitoring to derive robust data as a foundation for future ecosystem-based fish-stock and biodiversity management. The first example is from the NE Pacific Ocean where the deep-water sablefish (Anoplopoma fimbria) has been monitored since 2010 by the NEPTUNE cabled observatory operated by Ocean Networks Canada. The second example is from the NE Atlantic Ocean where the Norway lobster (Nephrops norvegicus) is being monitored using the SmartBay observatory developed for the European Multidisciplinary Seafloor and water column Observatories. Drawing from these two examples, we provide insights into the technological challenges and future steps required to develop full-scale fishery-independent stock assessments. [ABSTRACT FROM AUTHOR]
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- 2020
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10. Marine Science Can Contribute to the Search for Extra-Terrestrial Life.
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Aguzzi J, Cuadros J, Dartnell L, Costa C, Violino S, Canfora L, Danovaro R, Robinson NJ, Giovannelli D, Flögel S, Stefanni S, Chatzievangelou D, Marini S, Picardi G, and Foing B
- Abstract
Life on our planet likely evolved in the ocean, and thus exo-oceans are key habitats to search for extraterrestrial life. We conducted a data-driven bibliographic survey on the astrobiology literature to identify emerging research trends with marine science for future synergies in the exploration for extraterrestrial life in exo-oceans. Based on search queries, we identified 2592 published items since 1963. The current literature falls into three major groups of terms focusing on (1) the search for life on Mars, (2) astrobiology within our Solar System with reference to icy moons and their exo-oceans, and (3) astronomical and biological parameters for planetary habitability. We also identified that the most prominent research keywords form three key-groups focusing on (1) using terrestrial environments as proxies for Martian environments, centred on extremophiles and biosignatures, (2) habitable zones outside of "Goldilocks" orbital ranges, centred on ice planets, and (3) the atmosphere, magnetic field, and geology in relation to planets' habitable conditions, centred on water-based oceans., Competing Interests: The authors declare no conflicts of interest.
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- 2024
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11. Underwater legged robotics: review and perspectives.
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Picardi G, Astolfi A, Chatzievangelou D, Aguzzi J, and Calisti M
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- Biomimetics methods, Locomotion, Robotics methods
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Nowadays, there is a growing awareness on the social and economic importance of the ocean. In this context, being able to carry out a diverse range of operations underwater is of paramount importance for many industrial sectors as well as for marine science and to enforce restoration and mitigation actions. Underwater robots allowed us to venture deeper and for longer time into the remote and hostile marine environment. However, traditional design concepts such as propeller driven remotely operated vehicles, autonomous underwater vehicles, or tracked benthic crawlers, present intrinsic limitations, especially when a close interaction with the environment is required. An increasing number of researchers are proposing legged robots as a bioinspired alternative to traditional designs, capable of yielding versatile multi-terrain locomotion, high stability, and low environmental disturbance. In this work, we aim at presenting the new field of underwater legged robotics in an organic way, discussing the prototypes in the state-of-the-art and highlighting technological and scientific challenges for the future. First, we will briefly recap the latest developments in traditional underwater robotics from which several technological solutions can be adapted, and on which the benchmarking of this new field should be set. Second, we will the retrace the evolution of terrestrial legged robotics, pinpointing the main achievements of the field. Third, we will report a complete state of the art on underwater legged robots focusing on the innovations with respect to the interaction with the environment, sensing and actuation, modelling and control, and autonomy and navigation. Finally, we will thoroughly discuss the reviewed literature by comparing traditional and legged underwater robots, highlighting interesting research opportunities, and presenting use case scenarios derived from marine science applications., (© 2023 IOP Publishing Ltd.)
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- 2023
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12. Established and Emerging Research Trends in Norway Lobster, Nephrops norvegicus .
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Aguzzi J, Violino S, Costa C, Bahamon N, Navarro J, Chatzievangelou D, Robinson NJ, Doyle J, Martinelli M, Lordan C, and Company JB
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The burrowing crustacean decapod Nephrops norvegicus is a significant species in European Atlantic and Mediterranean fisheries. Research over the decades has mainly focused on behavioral and physiological aspects related to the burrowing lifestyle, since animals can only be captured by trawls when engaged in emergence on the seabed. Here, we performed a global bibliographic survey of all the scientific literature retrieved in SCOPUS since 1965, and terminology maps were produced with the VOSviewer software to reveal established and emerging research areas. We produced three term-map plots: term clustering, term citation, and term year. The term clustering network showed three clusters: fishery performance, assessment, and management; biological cycles in growth, reproduction, and behavior; and finally, physiology and ecotoxicology, including food products. The term citation map showed that intense research is developed on ecotoxicology and fishery management. Finally, the term year map showed that the species was first studied in its morphological and physiological aspects and more recently in relation to fishery and as a food resource. Taken together, the results indicate scarce knowledge on how burrowing behavior and its environmental control can alter stock assessment, because of the poor use of current and advanced monitoring technologies.
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- 2023
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13. Research Trends and Future Perspectives in Marine Biomimicking Robotics.
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Aguzzi J, Costa C, Calisti M, Funari V, Stefanni S, Danovaro R, Gomes HI, Vecchi F, Dartnell LR, Weiss P, Nowak K, Chatzievangelou D, and Marini S
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Mechatronic and soft robotics are taking inspiration from the animal kingdom to create new high-performance robots. Here, we focused on marine biomimetic research and used innovative bibliographic statistics tools, to highlight established and emerging knowledge domains. A total of 6980 scientific publications retrieved from the Scopus database (1950-2020), evidencing a sharp research increase in 2003-2004. Clustering analysis of countries collaborations showed two major Asian-North America and European clusters. Three significant areas appeared: (i) energy provision, whose advancement mainly relies on microbial fuel cells, (ii) biomaterials for not yet fully operational soft-robotic solutions; and finally (iii), design and control, chiefly oriented to locomotor designs. In this scenario, marine biomimicking robotics still lacks solutions for the long-lasting energy provision, which presently hinders operation autonomy. In the research environment, identifying natural processes by which living organisms obtain energy is thus urgent to sustain energy-demanding tasks while, at the same time, the natural designs must increasingly inform to optimize energy consumption.
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- 2021
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14. Quality Control and Pre-Analysis Treatment of the Environmental Datasets Collected by an Internet Operated Deep-Sea Crawler during Its Entire 7-Year Long Deployment (2009-2016).
- Author
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Chatzievangelou D, Aguzzi J, Scherwath M, and Thomsen L
- Abstract
Deep-sea environmental datasets are ever-increasing in size and diversity, as technological advances lead monitoring studies towards long-term, high-frequency data acquisition protocols. This study presents examples of pre-analysis data treatment steps applied to the environmental time series collected by the Internet Operated Deep-sea Crawler "Wally" during a 7-year deployment (2009-2016) in the Barkley Canyon methane hydrates site, off Vancouver Island (BC, Canada). Pressure, temperature, electrical conductivity, flow, turbidity, and chlorophyll data were subjected to different standardizing, normalizing, and de-trending methods on a case-by-case basis, depending on the nature of the treated variable and the range and scale of the values provided by each of the different sensors. The final pressure, temperature, and electrical conductivity (transformed to practical salinity) datasets are ready for use. On the other hand, in the cases of flow, turbidity, and chlorophyll, further in-depth processing, in tandem with data describing the movement and position of the crawler, will be needed in order to filter out all possible effects of the latter. Our work evidences challenges and solutions in multiparametric data acquisition and quality control and ensures that a big step is taken so that the available environmental data meet high quality standards and facilitate the production of reliable scientific results.
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- 2020
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15. The Hierarchic Treatment of Marine Ecological Information from Spatial Networks of Benthic Platforms.
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Aguzzi J, Chatzievangelou D, Francescangeli M, Marini S, Bonofiglio F, Del Rio J, and Danovaro R
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- Artificial Intelligence, Conservation of Natural Resources methods, Environmental Monitoring methods, Marine Biology methods
- Abstract
Measuring biodiversity simultaneously in different locations, at different temporal scales, and over wide spatial scales is of strategic importance for the improvement of our understanding of the functioning of marine ecosystems and for the conservation of their biodiversity. Monitoring networks of cabled observatories, along with other docked autonomous systems (e.g., Remotely Operated Vehicles [ROVs], Autonomous Underwater Vehicles [AUVs], and crawlers), are being conceived and established at a spatial scale capable of tracking energy fluxes across benthic and pelagic compartments, as well as across geographic ecotones. At the same time, optoacoustic imaging is sustaining an unprecedented expansion in marine ecological monitoring, enabling the acquisition of new biological and environmental data at an appropriate spatiotemporal scale. At this stage, one of the main problems for an effective application of these technologies is the processing, storage, and treatment of the acquired complex ecological information. Here, we provide a conceptual overview on the technological developments in the multiparametric generation, storage, and automated hierarchic treatment of biological and environmental information required to capture the spatiotemporal complexity of a marine ecosystem. In doing so, we present a pipeline of ecological data acquisition and processing in different steps and prone to automation. We also give an example of population biomass, community richness and biodiversity data computation (as indicators for ecosystem functionality) with an Internet Operated Vehicle (a mobile crawler). Finally, we discuss the software requirements for that automated data processing at the level of cyber-infrastructures with sensor calibration and control, data banking, and ingestion into large data portals.
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- 2020
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16. New High-Tech Flexible Networks for the Monitoring of Deep-Sea Ecosystems.
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Aguzzi J, Chatzievangelou D, Marini S, Fanelli E, Danovaro R, Flögel S, Lebris N, Juanes F, De Leo FC, Del Rio J, Thomsen L, Costa C, Riccobene G, Tamburini C, Lefevre D, Gojak C, Poulain PM, Favali P, Griffa A, Purser A, Cline D, Edgington D, Navarro J, Stefanni S, D'Hondt S, Priede IG, Rountree R, and Company JB
- Subjects
- Mining, Biodiversity, Ecosystem
- Abstract
Increasing interest in the acquisition of biotic and abiotic resources from within the deep sea (e.g., fisheries, oil-gas extraction, and mining) urgently imposes the development of novel monitoring technologies, beyond the traditional vessel-assisted, time-consuming, high-cost sampling surveys. The implementation of permanent networks of seabed and water-column-cabled (fixed) and docked mobile platforms is presently enforced, to cooperatively measure biological features and environmental (physicochemical) parameters. Video and acoustic (i.e., optoacoustic) imaging are becoming central approaches for studying benthic fauna (e.g., quantifying species presence, behavior, and trophic interactions) in a remote, continuous, and prolonged fashion. Imaging is also being complemented by in situ environmental-DNA sequencing technologies, allowing the traceability of a wide range of organisms (including prokaryotes) beyond the reach of optoacoustic tools. Here, we describe the different fixed and mobile platforms of those benthic and pelagic monitoring networks, proposing at the same time an innovative roadmap for the automated computing of hierarchical ecological information on deep-sea ecosystems (i.e., from single species' abundance and life traits to community composition, and overall biodiversity).
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- 2019
- Full Text
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17. Seasonal monitoring of deep-sea megabenthos in Barkley Canyon cold seep by internet operated vehicle (IOV).
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Doya C, Chatzievangelou D, Bahamon N, Purser A, De Leo FC, Juniper SK, Thomsen L, and Aguzzi J
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- Internet, Seasons, Seawater
- Abstract
Knowledge of the processes shaping deep-sea benthic communities at seasonal scales in cold-seep environments is incomplete. Cold seeps within highly dynamic regions, such as submarine canyons, where variable current regimes may occur, are particularly understudied. Novel Internet Operated Vehicles (IOVs), such as tracked crawlers, provide new techniques for investigating these ecosystems over prolonged periods. In this study a benthic crawler connected to the NEPTUNE cabled infrastructure operated by Ocean Networks Canada was used to monitor community changes across 60 m2 of a cold-seep area of the Barkley Canyon, North East Pacific, at ~890 m depth within an Oxygen Minimum Zone (OMZ). Short video-transects were run at 4-h intervals during the first week of successive calendar months, over a 14 month period (February 14th 2013 to April 14th 2014). Within each recorded transect video megafauna abundances were computed and changes in environmental conditions concurrently measured. The responses of fauna to environmental conditions as a proxy of seasonality were assessed through analysis of abundances in a total of 438 video-transects (over 92 h of total footage). 7698 fauna individuals from 6 phyla (Cnidaria, Ctenophora, Arthropoda, Echinodermata, Mollusca, and Chordata) were logged and patterns in abundances of the 7 most abundant taxa (i.e. rockfish Sebastidae, sablefish Anoplopoma fimbria, hagfish Eptatretus stoutii, buccinids (Buccinoidea), undefined small crabs, ctenophores Bolinopsis infundibulum, and Scyphomedusa Poralia rufescens) were identified. Patterns in the reproductive behaviour of the grooved tanner crab (Chionnecetes tanneri) were also indicated. Temporal variations in biodiversity and abundance in megabenthic fauna was significantly influenced by variabilities in flow velocity flow direction (up or down canyon), dissolved oxygen concentration and month of study. Also reported here for the first time are transient mass aggregations of grooved tanner crabs through these depths of the canyon system, in early spring and likely linked to the crab's reproductive cycle.
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- 2017
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18. High-Frequency Patterns in the Abundance of Benthic Species near a Cold-Seep - An Internet Operated Vehicle Application.
- Author
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Chatzievangelou D, Doya C, Thomsen L, Purser A, and Aguzzi J
- Subjects
- Animals, Brachyura physiology, Canada, Hagfishes physiology, Seasons, Chordata, Nonvertebrate physiology
- Abstract
Three benthic megafaunal species (i.e. sablefish Anoplopoma fimbria; pacific hagfish Eptatretus stoutii and a group of juvenile crabs) were tested for diel behavioral patterns at the methane hydrates site of Barkley Canyon (890 m depth), off Vancouver Island (BC, Canada). Fluctuations of animal counts in linear video-transects conducted with the Internet Operated Deep-Sea Crawler "Wally" in June, July and December of 2013, were used as proxy of population activity rhythms. Count time series and environmental parameters were analyzed under the hypothesis that the environmental conditioning of activity rhythms depends on the life habits of particular species (i.e. movement type and trophic level). Non-linear least squares modeling of biological time series revealed significant diel periods for sablefish in summer and for hagfish and crabs in December. Combined cross-correlation and redundancy (RDA) analyses showed strong relationships among environmental fluctuations and detected megafauna. In particular, sablefish presence during summer months was related to flow magnitude, while the activity of pacific hagfish and juvenile crabs in December correlated with change in chemical parameters (i.e. chlorophyll and oxygen concentrations, respectively). Waveform analyses of animal counts and environmental variables confirmed the phase delay during the 24 h cycle. The timing of detection of sablefish occurred under low flow velocities, a possible behavioral adaptation to the general hypoxic conditions. The proposed effect of chlorophyll concentrations on hagfish counts highlights the potential role of phytodetritus as an alternative food source for this opportunistic feeder. The juvenile crabs seemed to display a cryptic behavior, possibly to avoid predation, though this was suppressed when oxygen levels were at a minimum. Our results highlight the potential advantages such mobile observation platforms offer in multiparametric deep-sea monitoring in terms of both spatial and temporal resolution and add to the vastly understudied field of diel rhythms of deep-sea megafauna., Competing Interests: Ocean Networks Canada and Neptune Canada (www.oceannetworks.ca/) partially funded the development and deployment of the crawler. The authors declare that this does not alter our adherence to PLOS ONE policies on sharing data and materials.
- Published
- 2016
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