Worldwide Soundscapes: A Synthesis of Passive Acoustic Monitoring Across Realms Kevin F. A. Darras, Rodney A. Rountree, Steven L. Van Wilgenburg, Anna F. Cord, Frederik Pitz, et al. Global Ecology and Biogeography, 2025 AimThe urgency for remote, reliable and scalable biodiversity monitoring amidst mounting human pressures on ecosystems has sparked worldwide interest in Passive Acoustic Monitoring (PAM), which can track life underwater and on land. However, we lack a unified methodology to report this sampling effort and a comprehensive overview of PAM coverage to gauge its potential as a global research and monitoring tool. To address this gap, we created the Worldwide Soundscapes project, a collaborative network and growing database comprising metadata from 416 datasets across all realms (terrestrial, marine, freshwater and subterranean).LocationWorldwide, 12,343 sites, all ecosystem types.Time Period1991 to present.Major Taxa StudiedAll soniferous taxa.MethodsWe synthesise sampling coverage across spatial, temporal and ecological scales using metadata describing sampling locations, deployment schedules, focal taxa and audio recording parameters. We explore global trends in biological, anthropogenic and geophysical sounds based on 168 selected recordings from 12 ecosystems across all realms.ResultsTerrestrial sampling is spatially denser (46 sites per million square kilometre—Mkm2) than aquatic sampling (0.3 and 1.8 sites/Mkm2 in oceans and fresh water) with only two subterranean datasets. Although diel and lunar cycles are well sampled across realms, only marine datasets (55%) comprehensively sample all seasons. Across the 12 ecosystems selected for exploring global acoustic trends, biological sounds showed contrasting diel patterns across ecosystems, declined with distance from the Equator, and were negatively correlated with anthropogenic sounds.Main ConclusionsPAM can inform macroecological studies as well as global conservation and phenology syntheses, but representation can be improved by expanding terrestrial taxonomic scope, sampling coverage in the high seas and subterranean ecosystems, and spatio‐temporal replication in freshwater habitats. Overall, this worldwide PAM network holds promise to support cross‐realm biodiversity research and monitoring efforts.
Power Gain from Energy Harvesting Sources at High MPPT Sampling Rates Manel Gasulla, Matias Carandell Sensors, 2023 Energy harvesting (EH) sources require the tracking of their maximum power point (MPP) to ensure that maximum energy is captured. This tracking process, performed by an MPP tracker (MPPT), is performed by periodically measuring the EH transducer’s output at a given sampling rate. The harvested power as a function of the sampling parameters has been analyzed in a few works, but the power gain achieved with respect to the case of a much slower sampling rate than the EH source’s frequency has not been assessed so far. In this work, simple expressions are obtained that predict this gain assuming a Thévenin equivalent for the EH transducer. It is shown that the power gain depends on the relationship between the square of AC to DC open circuit voltage of the EH transducer. On the other hand, it is proven that harvested power increases, using a suitable constant signal for the MPP voltage instead of tracking the MPP at a low sampling rate. Experimental results confirmed the theoretical predictions. First, a function generator with a series resistor of 1 kΩ was used, emulating a generic Thévenin equivalent EH. Three waveform types were used (sinus, square, and triangular) with a DC voltage of 2.5 V and AC rms voltage of 0.83 V. A commercial MPPT with a fixed sampling rate of 3 Hz was used and the frequency of the waveforms was changed from 50 mHz to 50 Hz, thus effectively emulating different sampling rates. Experimental power gains of 11.1%, 20.7%, and 7.43% were, respectively, achieved for the sinus, square, and triangular waves, mainly agreeing with the theoretical predicted ones. Then, experimental tests were carried out with a wave energy converter (WEC) embedded into a drifter and attached to a linear shaker, with a sinus excitation frequency of 2 Hz and peak-to-peak amplitude of 0.4 g, in order to emulate the drifter’s movement under a sea environment. The WEC provided a sinus-like waveform. In this case, another commercial MPPT with a sampling period of 16 s was used for generating a slow sampling rate, whereas a custom MPPT with a sampling rate of 60 Hz was used for generating a high sampling rate. A power gain around 20% was achieved in this case, also agreeing with the predicted gain.
Experimental Validation of a Fast-Tracking FOCV-MPPT Circuit for a Wave Energy Converter Embedded into an Oceanic Drifter Matias Carandell, Daniel Mihai Toma, Andrew S. Holmes, Joaquín del Río, Manel Gasulla Journal of Marine Science and Engineering, 2023 Wave Energy Converters (WECs) are an ideal solution for expanding the autonomy of surface sensor platforms such as oceanic drifters. To extract the maximum amount of energy from these fast-varying sources, a fast maximum power point tracking (MPPT) technique is required. Previous studies have examined power management units (PMU) with fast MPPT circuits, but none of them have demonstrated their feasibility in a real-world scenario. In this study, the performance of a fast-tracking fractional open circuit voltage (FOCV)-MPPT circuit (sampling period TMPPT of 48 ms) is compared with a commercial slow-tracking PMU (TMPPT of 16 s) in a monitored sea area while using a small-scale, pendulum-type WEC. A specific low-power relaxation oscillator circuit is designed to control the fast MPPT circuit. The results demonstrate that by speeding up the sampling frequency of the MPPT circuit, the harvested energy can be increased by a factor of three.
A New Coastal Crawler Prototype to Expand the Ecological Monitoring Radius of OBSEA Cabled Observatory Ahmad Falahzadeh, Daniel Mihai Toma, Marco Francescangeli, Damianos Chatzievangelou, Marc Nogueras, et al. Journal of Marine Science and Engineering, 2023 The use of marine cabled video observatories with multiparametric environmental data collection capability is becoming relevant for ecological monitoring strategies. Their ecosystem surveying can be enforced in real time, remotely, and continuously, over consecutive days, seasons, and even years. Unfortunately, as most observatories perform such monitoring with fixed cameras, the ecological value of their data is limited to a narrow field of view, possibly not representative of the local habitat heterogeneity. Docked mobile robotic platforms could be used to extend data collection to larger, and hence more ecologically representative areas. Among the various state-of-the-art underwater robotic platforms available, benthic crawlers are excellent candidates to perform ecological monitoring tasks in combination with cabled observatories. Although they are normally used in the deep sea, their high positioning stability, low acoustic signature, and low energetic consumption, especially during stationary phases, make them suitable for coastal operations. In this paper, we present the integration of a benthic crawler into a coastal cabled observatory (OBSEA) to extend its monitoring radius and collect more ecologically representative data. The extension of the monitoring radius was obtained by remotely operating the crawler to enforce back-and-forth drives along specific transects while recording videos with the onboard cameras. The ecological relevance of the monitoring-radius extension was demonstrated by performing a visual census of the species observed with the crawler’s cameras in comparison to the observatory’s fixed cameras, revealing non-negligible differences. Additionally, the videos recorded from the crawler’s cameras during the transects were used to demonstrate an automated photo-mosaic of the seabed for the first time on this class of vehicles. In the present work, the crawler travelled in an area of 40 m away from the OBSEA, producing an extension of the monitoring field of view (FOV), and covering an area approximately 230 times larger than OBSEA’s camera. The analysis of the videos obtained from the crawler’s and the observatory’s cameras revealed differences in the species observed. Future implementation scenarios are also discussed in relation to mission autonomy to perform imaging across spatial heterogeneity gradients around the OBSEA.
Nonlinear dynamic analysis of pendulum‐type wave energy converter for low‐power marine monitoring applications Proceedings of the European Wave and Tidal Energy Conference, 2021
Boyas Pop-Up Autónomas para la Transmisión de Datos en Tiempo Casi Real desde Observatorios Submarinos M Carandell, I Masmitja, P Agúndez Fernández, C Vega Institute of Electrical and Electronics Engineers , 2026 2026
Wave Energy Converter for Drifter Applications (WECDA) Z Hadas, J Moravec, M Kvassay, M Carandell Widmer 2026
An Open Toolkit for Underwater Field Robotics G Picardi, S Iacoponi, M Carandell, J Aguirregomezcorta, M Chellapurath, ... arXiv preprint arXiv:2512.15597 , 2025 2025
Artificial reef based ecosystem design and monitoring M Francescangeli, DM Toma, V Mendizábal, M Carandell, E Martínez, ... Ecological Engineering 221, 107752 , 2025 2025 Citations: 3
Interconnected robotic platforms inform deep-sea ecological restoration trends I Masmitja, N Palomeras, DM Toma, N Bahamon, M Carandell, ... Marine pollution bulletin 219, 118314 , 2025 2025 Citations: 5
A digital-twin strategy using robots for marine ecosystem monitoring J Aguzzi, E Chatzidouros, D Chatzievangelou, M Clavel-Henry, S Flögel, ... Ecological Informatics, 103409 , 2025 2025 Citations: 10
Deep learning for automated fish detection in underwater images: a tool for sustainable marine ecosystem monitoring O Prat Bayarri, P Baños Castelló, E Martínez Padró, M Francescangeli, ... IntechOpen , 2025 2025 Citations: 3
Compression and segmentation methods on Argos-based image transmission for environmental seafloor monitoring C De La Vega, J Armajach, I Masmitja, J Del Río, M Carandell OCEANS 2025 Brest, 1-8 , 2025 2025
Geolocation and tracking of pop-up buoys using ADALM-PLUTO software-defined radio on a BlueBoat unmanned surface vessel J Armajach, M Carandell, C De La Vega, J Del Río, J Aguzzi, I Masmitja OCEANS 2025 Brest, 1-8 , 2025 2025
Development of low-cost underwater cameras for remote monitoring of marine ecosystems with ai-based species detection P Baños Castelló, C de la Vega, O Prat i Bayarri, M Carandell Widmer, ... Instrumentation viewpoint, 105-106 , 2025 2025
An update of the ongoing study of low-cost and highly scalable posidonia oceanica replantation methods F Veger, M Carandell Widmer, M Francescangeli, D Mihai Toma, ... Instrumentation viewpoint, 98-99 , 2025 2025
Automated integration of metrological metadata into oceanographic datasets E Martínez, A Garcia Benadí, F Salvetat, M Carandell Widmer, ... Instrumentation viewpoint, 147-147 , 2025 2025
CLS woodbuoy: transitioning towards an eco-friendly marine data collection platform M Lucas, P de Saint Léger, OD de Gesincourt, MC Widmer Instrumentation Viewpoint , 2025 2025
Monitoring marine ph with the anb aq50 sensor integrated into the obsea observatory M Nogueras Cervera, A Mielczarek, D Mihai Toma, M Carandell Widmer, ... Instrumentation viewpoint, 114-115 , 2025 2025
Enhancing species video detection capabilities at the obsea observatory through the integration of emuas cameras within the aneris project framework O Prat i Bayarri, P Baños Castelló, M Carandell Widmer, E Martínez, ... Instrumentation viewpoint, 107-108 , 2025 2025
Autonomous movement of obsea underwater crawler for monitoring underwater environments A Falahzadehabarghouee, D Mihai Toma, M Nogueras Cervera, ... Instrumentation viewpoint, 109-110 , 2025 2025
Advancements in pop-up buoy technology for enhancing seafloor data collection: insights from a year of trials M Carandell Widmer, D Toma, E Martínez, C de la Vega, ... Instrumentation viewpoint, 64-65 , 2025 2025
Compression and Segmentation Methods on Argos-Based Image Transmission for Environmental Seafloor Monitoring C Vega, J Armajach, I Masmitja, J Río, M Carandell Institute of Electrical and Electronics Engineers , 2025 2025
AI-based fish detections at Slagreef biotop deployed near the OBSEA Underwater Observatory [Dataset] E Martínez, O Prat Bayarri, P Baños Castelló, M Francescangeli, ... Zenodo , 2025 2025
Advancing marine technologies: the crucial role of observatories in the development of operational marine biology-a case study of the emso observatories smartbay and obsea in … AM de Lecea, P Gaughan, A Berry, C O'Malley, S Burke, ... Instrumentation viewpoint, 87-88 , 2025 2025
MOST CITED SCHOLAR PUBLICATIONS
Obsea: a decadal balance for a cabled observatory deployment J Del-Rio, M Nogueras, DM Toma, E Martínez, C Artero-Delgado, I Bghiel, ... IEEE access 8, 33163-33177 , 2020 2020 Citations: 96
Design and testing of a kinetic energy harvester embedded into an oceanic drifter M Carandell, DM Toma, M Carbonell, J del Rio, M Gasulla IEEE Sensors Journal 20 (23), 13930-13939 , 2020 2020 Citations: 66
A new coastal crawler prototype to expand the ecological monitoring radius of OBSEA cabled observatory A Falahzadeh, DM Toma, M Francescangeli, D Chatzievangelou, ... Journal of Marine Science and Engineering 11 (4), 857 , 2023 2023 Citations: 22
Effect of the sampling parameters in FOCV-MPPT circuits for fast-varying EH sources M Carandell, AS Holmes, DM Toma, J del Rio, M Gasulla IEEE Transactions on Power Electronics 38 (2), 2695-2708 , 2022 2022 Citations: 15
Electromagnetic rolling mass wave energy harvester for oceanic drifter applications M Carandell, J Tichy, J Smilek, DM Toma, M Gasulla, J del Río, Z Hadas The European Physical Journal Special Topics 231 (8), 1475-1484 , 2022 2022 Citations: 15
Expanding the underwater communication capabilities of seafloor ecosystem monitoring stand-alone platforms using pop-up buoys M Carandell, S Hernández, DM Toma, E Martínez, M Nogueras, J Aguzzi, ... OCEANS 2023-Limerick, 1-7 , 2023 2023 Citations: 14
Multiparametric benthic landers for monitoring fishing-impacted deep-sea ecosystems DM Toma, J Aguzzi, M Carandell, M Nogueras, E Martínez, ... OCEANS 2023-Limerick, 1-5 , 2023 2023 Citations: 13
Design and development of a kinetic energy harvester device for oceanic drifter applications M Carandell, DM Toma, M Carbonell, M Gasulla, J del Río 2019 IEEE International Instrumentation and Measurement Technology … , 2019 2019 Citations: 11
A digital-twin strategy using robots for marine ecosystem monitoring J Aguzzi, E Chatzidouros, D Chatzievangelou, M Clavel-Henry, S Flögel, ... Ecological Informatics, 103409 , 2025 2025 Citations: 10
Evaluation of Sigfox LPWAN technology for autonomous sensors in coastal applications M Carandell Widmer, D Toma, J Río Fernández, K Ganchev, ... Instrumentation Viewpoint, 36-37 , 2018 2018 Citations: 10
Impact on the wave parameters estimation of a kinetic energy harvester embedded into a drifter M Carandell, DM Toma, JP Pinto, M Gasulla, J del Río Global Oceans 2020: Singapore–US Gulf Coast, 1-6 , 2020 2020 Citations: 8
Experimental validation of a kinetic energy harvester device for oceanic drifter applications M Carandell, DM Toma, M Gasulla, J del Río OCEANS 2019-Marseille, 1-7 , 2019 2019 Citations: 7
Performance of WAVY ocean Lagrangian drifters for surface characterization of ocean dynamic structures DM Toma, M Carandell, J del Río 2022 IEEE International Workshop on Metrology for the Sea; Learning to … , 2022 2022 Citations: 6
Optimum MPPT strategy for low-power pendulum-type wave energy converters M Carandell, DM Toma, J del Río, M Gasulla 2020 IEEE SENSORS, 1-4 , 2020 2020 Citations: 6
Interconnected robotic platforms inform deep-sea ecological restoration trends I Masmitja, N Palomeras, DM Toma, N Bahamon, M Carandell, ... Marine pollution bulletin 219, 118314 , 2025 2025 Citations: 5
Experimental validation of a fast-tracking FOCV-MPPT circuit for a wave energy converter embedded into an oceanic drifter M Carandell, DM Toma, AS Holmes, J del Río, M Gasulla Journal of Marine Science and Engineering 11 (4), 816 , 2023 2023 Citations: 5
Tele-operated ecological monitoring at the seafloor observatory (OBSEA) A Falahzadeh, J Aguzzi, M Nogueras Cervera, D Toma, ... Instrumentation Viewpoint, 18-18 , 2021 2021 Citations: 5
An e-infrastructure for FAIR data management of underwater observatories E Martínez, A Garcia-Benadí, DM Toma, M Carandell, M Nogueras, ... OCEANS 2023-Limerick, 1-6 , 2023 2023 Citations: 4
Power gain from energy harvesting sources at high MPPT sampling rates M Gasulla, M Carandell Sensors 23 (9), 4388 , 2023 2023 Citations: 4
Nonlinear dynamic analysis of pendulum-type Wave Energy Converter for low-power marine monitoring applications M Carandell Widmer, D Toma, P Alevras, M Gasulla Forner, ... Proceedings of the European Wave and Tidal Energy Conference: 14th EWTEC … , 2021 2021 Citations: 4
