Ocean Networks Research Articles

TF-REF-RNN: Time-Frequency and Reference Signal Feature Fusion Recurrent Neural Network for Underwater Backscatter Signal Separation

Underwater wireless sensor networks play an important role in exploring the oceans as part of an integrated space–air–ground–ocean network. Because underwater energy is limited, the equipment’s efficiency is significantly impacted by the battery duration. Underwater backscatter technology does not require batteries and has significant potential in positioning, navigation, communication, and sensing due to its passive characteristics. However, underwater backscatter signals are susceptible to being swamped by the excitation signal. Additionally, the signals from different reflection signals share the same frequency and overlap, and contain fewer useful features, leading to significant challenges in detection. In order to solve the above problems, this paper proposes a recurrent neural network that introduces time-frequency and reference signal features for underwater backscatter signal separation (TF-REF-RNN). In the feature extraction part, we design an encoder that introduces time-frequency domain features to learn more about the frequency details. Additionally, to improve performance, we designed a separator that incorporates the reference signal’s pure global information features. The proposed TF-REF-RNN network model achieves metrics of 28.55 dB SI-SNRi and 19.51 dB SDRi in the dataset that includes shipsEar noise data and underwater simulated backscatter signals, outperforming similar classical methods.

High-frequency study of megafaunal communities on whale bone, wood and carbonate in hypoxic Barkley Canyon

Organic-rich whale bones and wood falls occur widely in the deep sea and support diverse faunal communities, contributing to seafloor habitat diversity. Changes in community structure through succession on deep-sea bone/wood substrates are modulated by ecosystem engineers, i.e., bone-eating Osedax annelids, and wood-boring Xylophaga bivalves. Here, we use a comparative experimental approach and Ocean Networks Canada’s (ONC) cabled observatory in hypoxic Barkley Canyon to study, at high temporal resolution, colonization and succession on whale-bone, Douglas fir wood, and control carbonate rock over 8.3 mo. Experimental substrates were similar in size and mounted on PVC plates near the seafloor at 890 m depth and monitored by high-definition video camera for 5-min intervals every 6-12 h over a period of 8.3 mo. A broad range of seafloor and sea-surface environmental variables were also monitored at this site over the 8.3 mo to account for environmental variability and food input. Following loss of the high-definition camera, substrates were surveyed approximately annually with lower resolution ROV video for an additional 8.5 y. We find that megafaunal abundances, species diversity, and community structure varied substantially over 8.3 mo on each substrate, with markedly different patterns on whale bones due to the development of extensive white bacterial mats. A combination of seafloor and sea surface variables explained < 35% of bone/wood community variation. Bone-eating Osedax annelids failed to colonize whale bones even after 9.2 years, and boring Xylophaga bivalves colonized the wood at much lower rates than in better oxygenated deep-sea locations. Species diversity on whale-bone and wood substrates appeared to be substantially reduced due to the absence of ecosystem engineers and the low oxygen concentrations. We hypothesize that Osedax/Xylophaga colonization, bone/wood degradation, and bone/wood community development may be limited by oxygen concentrations of 0.22 - 0.33 ml.l on the NE Pacific margin, and that OMZ expansion due to climate change will reduce whale-bone and wood degradation, and the contribution of whale falls and wood falls to beta diversity, on the NE Pacific margin.

Ocean surface radiation measurement best practices

Ocean surface radiation measurement best practices have been developed as a first step to support the interoperability of radiation measurements across multiple ocean platforms and between land and ocean networks. This document describes the consensus by a working group of radiation measurement experts from land, ocean, and aircraft communities. The scope was limited to broadband shortwave (solar) and longwave (terrestrial infrared) surface irradiance measurements for quantification of the surface radiation budget. Best practices for spectral measurements for biological purposes like photosynthetically active radiation and ocean color are only mentioned briefly to motivate future interactions between the physical surface flux and biological radiation measurement communities. Topics discussed in these best practices include instrument selection, handling of sensors and installation, data quality monitoring, data processing, and calibration. It is recognized that platform and resource limitations may prohibit incorporating all best practices into all measurements and that spatial coverage is also an important motivator for expanding current networks. Thus, one of the key recommendations is to perform interoperability experiments that can help quantify the uncertainty of different practices and lay the groundwork for a multi-tiered global network with a mix of high-accuracy reference stations and lower-cost platforms and practices that can fill in spatial gaps.

Glimpsing the 2020 spring bloom in the Strait of Georgia (Canada) with autonomous ferry-based sensors

Spatiotemporal observations are data rich and offer insights into links between ecological patterns and underlying processes. We present fine-scale autonomous observations from repeated ferry transects in the Strait of Georgia (British Columbia, Canada) during the 2020 spring bloom period using a FerryBox system (temperature, salinity, chlorophyll a fluorescence) and a digital inline holographic microscope. Despite instrument cleaning interruptions related to COVID-19 restrictions, 3 periods from late winter (February) to springtime (March and April) contained 14 days of high-quality holograms (>70000) capturing >10500 identifiable micro- to mesoplankton using automatic object detection. The ferry set-up provided automatic data storage through Ocean Networks Canada, which also automatized data flagging and guaranteed remote access. The highest-quality holograms repeatedly covered the central and eastern Strait and showed aspects of bloom succession. Fast-growing diatoms (Skeletonema sp.) emerged first, followed by a diverse assemblage including Chaetoceros spp., Ditylum spp., and Eucampia spp., and by April, larger centric cells prevailed. The combined approach captured local suppression of chlorophyll a fluorescence and diatom concentrations in Fraser River plume waters during the freshet, suggesting fine-scale spatial patterns in seasonal planktonic community composition. This work is among the first of its kind to autonomously generate in situ imaging and physicochemical data with spatiotemporal resolution.

Magnitude estimation and site characterization in southwestern British Columbia: application to earthquake early warning

In this study, we took a close look at the Ocean Networks Canada’s earthquake early warning system in southwestern British Columbia through analysis of the magnitude estimates by this system and characterization of site conditions for both onshore and offshore stations. Using magnitude values estimated at each station, over hundreds of notifications, we provided station terms to correct the magnitudes for stations that systematically generate high or low magnitude values. Moreover, by compiling a rich ground motion amplitude dataset and applying the horizontal-to-vertical spectral ratio method from Fourier amplitude of acceleration and response spectral acceleration, we investigated site characterization through evaluation of non-linear site response behavior and estimation of the site dominant frequency (fpeak) and its peak amplitude (Apeak) for each station. In general, no strong evidence of non-linearity is observed at any stations considering the magnitude-distance distribution of ground motions in this study. Offshore sites show fpeak and Apeak in the range of approximately 1.7–6 Hz and 0.4–1.2 (in base-10 log unit), respectively, whereas onshore sites show approximately 1–6 Hz for fpeak and 0.3–0.7 (in base-10 log unit) for Apeak.

STRAW-b (STRings for Absorption length in Water-b): the second pathfinder mission for the Pacific Ocean Neutrino Experiment

Since 2018, the potential for a high-energy neutrino telescope, named the Pacific Ocean Neutrino Experiment (P-ONE), has been thoroughly examined by two pathfinder missions, STRAW and STRAW-b, short for STRAW and STRAW-b. The P-ONE project seeks to install a neutrino detector with a one cubic kilometer volume in the Cascadia Basin's deep marine surroundings, situated near the western shores of Vancouver Island, Canada. To assess the environmental conditions and feasibility of constructing a neutrino detector of that scale, the pathfinder missions, STRAW and STRAW-b, have been deployed at a depth of 2.7 km within the designated site for P-ONE and were connected to the NEPTUNE observatory, operated by Ocean Networks Canada (ONC). While STRAW focused on analyzing the optical properties of water in the Cascadia Basin, STRAW-b employed cameras and spectrometers to investigate the characteristics of bioluminescence in the deep-sea environment. This report introduces the STRAW-b concept, covering its scientific objectives and the instrumentation used. Furthermore, it discusses the design considerations implemented to guarantee a secure and dependable deployment process of STRAW-b. Additionally, it showcases the data collected by battery-powered loggers, which monitored the mechanical stress on the equipment throughout the deployment. The report also offers an overview of STRAW-b's operation, with a specific emphasis on the notable advancements achieved in the data acquisition (DAQ) system and its successful integration with the server infrastructure of ONC.

Watching the sunrise on our ocean planet in a new era of marine science

Abstract Over the last 30 years, ocean sciences have been undergoing a technological revolution. Changes include the transition of autonomous platforms from being interesting engineering projects to being critical tools for scientists studying a range of processes at sea. My career has benefitted immensely from these technical innovations, allowing me to be at sea (virtually) 365 days a year and operate ocean networks globally. While these technical innovations have opened many research doors, many aspects of oceanography are unchanged. In my experience, working/talking/scheming with scientists is most effective face-to-face. Despite the growing capabilities of robotic platforms, we will still need to go to sea on ships to conduct critical experiments. As the responsibilities of scientists expand with mandated outreach efforts, I strongly urge young scientists to leverage the expertise of Broader Impact professionals, who are increasingly available to our community, in order to maximize the effectiveness and efficiency of our outreach efforts. Given the increasing observations of change occurring in the ocean, our work is ever-more important while still being fun. I am blessed to have had a career as an oceanographer exploring this planet.

The 24th International Seaweed Symposium - ‘Seaweeds in a changing world’

The 24th edition of the International Seaweed Symposium (ISS), an academic-industry event that dates back to 1952, was held for the first time in Oceania. The local organizing committee chaired by Professor Catriona Hurd, Institute for Marine and Antarctic Studies, University of Tasmania, and Professor Michael A. Borowitzka, Murdoch University, Western Australia worked tirelessly to curate a program that balanced scientific rigor with engaging discussions, providing ample opportunities for networking and collaboration. “Seaweeds in a changing world” was the theme of this symposium, participants from 48 countries from all over the world attended this symposium from 19-24 February 2023. More than 576 on-site and 207 virtual participants registered for the Symposium who contributed to the success of this event. The International Seaweed Association (ISA) ensures the continued development of seaweed and its benefits and serves as a bridge between research academia and industry. The ISA is ready to celebrate the Silver Jubilee of the ISS and is also proud to announce that the 25th International Seaweed Symposium (ISS) will be held in Victoria, British Columbia, Canada, 4-9 May, 2025 with the Local support of Ocean Networks Canada, Cascadia Seaweed, and the Pacific Seaweed Industry Association (https://iss25.com).

Material modernities: Tracing Janbai’s gendered mobilities across the Indian Ocean

AbstractThis article uses techniques of microhistory to explore how Janbai, the third wife of Sir Tharia Topan, exerted economic, religious, and social influence in Indian Ocean networks. An Ismaili woman from a Gujarati trading family who lived in East Africa, Janbai lies outside of the social worlds that have dominated studies of Muslim modernity in South Asia, which centre on Sunni male professionals from North India. Janbai was illiterate and largely disconnected from textual debates about modernity. In fact, she was just the sort of woman that reformers castigated for their supposed attachment to religious superstitions and customary practices. In contrast, studying Janbai through an alternative frame of ‘material modernity’ reveals the complex biography of a women who neither conformed to the idealized ‘new’ woman, nor simply reproduced inherited practices. Instead, she navigated rapid social mobility, shifting geographies, and new technologies and institutions, particularly colonial law courts, in ways that echoed and departed from how women had long exercised agency. The article argues that scholars, by foregrounding textual archives and discursive analysis, have tended to reproduce the marginalization of women like Janbai. In contrast, looking to sources such as jewellery and photographs, and reading textual archives with greater attention to gendered patterns of consumption and investment, brings Janbai from the margins to the centre of our understanding of modernity. In addition to enriching our understanding of the lives of women, increased attention to materiality and visuality opens up critical new avenues for writing a more variegated history of Muslim modernity.

Pacific Ocean Neutrino Experiment

Following the breakthrough discoveries of very-high-energy neutrinos of astrophysical origin by IceCube, a new field of research, neutrino astronomy, was established in the previous decade. Even though two extragalactic point sources of such neutrinos have been identified by now, TXS 0506+056 and NGC 1068, the origin and processes of the creation of astrophysical neutrinos are still mostly unexplored. To advance quickly in this new field, more neutrino telescopes are needed. This article describes the current status and plans for the development of the Pacific Ocean Neutrino Experiment (P-ONE), which is under construction in the Pacific Ocean near Vancouver Island. The deployment of P-ONE is expected to start in 2025, exploiting the already available deep-sea infrastructure provided by Ocean Networks Canada. P-ONE will complement the existing IceCube, Baikal-GVD, and KM3NeT neutrino telescopes not only with its large detection volume, but also by providing insight into the southern celestial hemisphere, where the central region of the Galactic Plane is located.

Inferring benthic megafaunal sediment reworking activity in relation to bottom water oxygen in Barkley Canyon, NE Pacific from video and acoustic imaging analysis

Sediment reworking activity influences benthic functioning expressed as nutrient fluxes and carbon cycling. Multiple studies have addressed sediment reworking based on observations from individual instrument types (e.g., video camera, side-scan sonar, multibeam), but none have considered reworking based on two or more complementary instruments. We therefore analyzed deep-sea megafaunal and reworked sediment traces by combining and comparing observations from non-invasive instruments, an underwater video camera and a rotary sonar, as part of the node of Ocean Networks Canada's NEPTUNE cabled observatory, located at 396 m depth in Barkley Canyon Upper Slope, NE Pacific Ocean. Specifically, we examined sediment traces and benthic megafaunal communities during two different sampling periods (May and September 2013) and at two different spatial scales of analysis. The camera images (∼0.5 m2) documented significantly lower megafaunal density during the period of reduced oxygen concentrations (May). Although we did not observe significant differences in sediment trace diversity and density between the two study periods, we were interested in how the relief traces generated by unidentified gastropods (likely the family Solariellidae) influenced sediment mixing. Relief traces showed higher density in low oxygen (May, 1.87 count m−2) than in high oxygen (September, 1.17 count m−2) conditions. Sonar images (∼1268 m2), which lacked sufficient resolution to allow identification of benthic organisms, documented distributions of biological pits (regions of low backscatter), a significantly greater proportion of bioturbated seafloor area, and increased in pit size with increased oxygen levels. Pits dominated sonar images at this location and persisted through the two study periods. Most sonar field of view subsections showed a significant increase in circularity of pit shapes, likely explained by increased reworked sediment with increasing oxygen concentration. We conclude that, except for relief burrows, higher reworked sediment area coincided with the highest oxygen concentration, which aligns with previously established reduced metabolic activity by benthos adapted to oxygen minimum zones. Furthermore, we emphasize the complementarity of the two imaging techniques (video and sonar) in understanding deep-sea benthic ecosystem dynamics, as well as the importance of considering multiple spatial scales when investigating proxies of bioturbation activity.

Networked media and information ocean literacy: a transformative approach for UN ocean decade

The United Nations’ Ocean Decade calls for co-designing transformative science, ocean networks, and learning strategies to address ocean health decline and deep-blue social divides in ocean governance. Yet the transformative capacity to advance ocean sustainability pathways shared by the UN Ocean Decade ecosystem of partners is still under-realized in the early stages of this global campaign. This paper explores the conceptual and institutional implications of the combined use of marine learning networks (MLNs) and media and information ocean literacy (MIOL) approaches to strengthen capacities for ocean governance systems’ transformation (leadership, strategies, skills, and actions). We build upon an empirical case study of the self-organized, youth-led Brazilian Future Ocean Panel, applying a regional alternative to such a combined approach (namely Social-Environmental Educommunication) during a four-year transdisciplinary program. We reveal the synergistic benefits of MLNs and MIOL in empowering early-career ocean professionals and fostering their transformative capacity in ocean policymaking. Our findings emphasize the practical implications of these approaches for advancing ocean governance systems transformations in other regions. Insights are shared on MLNs and MIOL applications in the pursuit of transdisciplinary solutions, ocean governance transformation, capacity development, and effective responses to foundational challenges facing the UN Ocean Decade’s global efforts toward sustainability.

End-to-End Service Availability in Heterogeneous Multi-Tier Cloud–Fog–Edge Networks

With the evolution towards the interconnected future internet spanning satellites, aerial systems, terrestrial infrastructure, and oceanic networks, availability modeling becomes imperative to ensure reliable service. This paper presents a methodology to assess end-to-end availability in complex multi-tiered architectures using a Markov model tailored to the unique characteristics of cloud, fog, edge, and IoT layers. By quantifying individual tier reliability and combinations thereof, the approach enables setting availability targets during the design and evaluation of operational systems. In the paper, a methodology is proposed to construct a Markov model for the reliability of discrete tiers and end-to-end service availability in heterogeneous multi-tier cloud–fog–edge networks, and the model is demonstrated through numerical examples assessing availability in multi-tier networks. The numerical examples demonstrate the adaptability of the model to various topologies from conventional three-tier to arbitrary multi-level architectures. As connectivity becomes ubiquitous across heterogeneous devices and networks, the proposed approach and availability modeling provide an effective tool for reinforcing the future internet’s fault tolerance and service quality.

Transient sounds of hydrothermal vents

Transient acoustic signals were recently detected at the Main Endeavour Hydrothermal Vent Field which are believed to be generated by both geological and biological sources, including vent chimney collapse, impulsive geological signals, fish grunts, and snapping. These signals provide an opportunity for long-term passive acoustic monitoring of hydrothermal vent activity and ecology. This method offers advantages of longevity and robustness compared with other monitoring techniques, as the sensor can remain a safe distance away from the high-temperature, caustic vent fluid. Utilizing recordings from a bottom-mounted hydrophone on Ocean Networks Canada’s NEPTUNE observatory, a detector was implemented to identify and classify these signals in more than one year of acoustic data after 2016. While only a single hydrophone is available at this site, an array of three seismic accelerometers also on the NEPTUNE observatory was used to localize transient events when sufficient signal-to-noise ratio was available to provide confidence in the location estimate. Correlation of the transient sounds with seismic activity at the vent field was also evaluated, suggesting that passive acoustic monitoring can augment seismic records to provide additional information regarding geological activity at hydrothermal vent sites.

Energy partitioning of the underwater soundscape

A four-element three-dimensional hydrophone array has been deployed on the Strait of Georgia node of the Victoria Experimental Network Under the Sea (VENUS) since March 2020. To the present, continuous pressure time series data from the four sensors has been streamed ashore and made available by Ocean Networks Canada. A technique for classifying and partitioning ambient noise using the three-dimensional noise coherence function is applied to the recordings. The noise coherence (directionality) due to wind generated surface noise and individual ships is analytically modelled using measured environmental inputs such as the time varying sound speed profile and sediment properties from the measurement site and compared with the observation. The theoretical coherence curve is computed by mixing the contributing sources until a best-fit is found. Since the wind generated surface noise coherence is stable and independent of the source effective sound power per unit area, the contribution of ship noise to the soundscape can be exactly determined. Applying this algorithm to the long-term data set allows the relative contribution of ship noise to the soundscape in the region to summarized succinctly. [Research supported by ONR.]

Enabling long-term soundscape observation via Ocean Networks Canada’s acoustic Northeast-Pacific infrastructure

Data time series covering extended periods of time in support of long-term environmental studies are particularly difficult and expensive to collect, especially at offshore locations. Ocean Networks Canada’s (ONC) undersea cabled observatories in the Northeast Pacific ocean have been collecting an extensive array of oceanographic, seismic, geophysical, biological and acoustical data over periods that, in some cases, extend beyond sixteen years. With regard to soundscape studies, ONC currently owns and operates 22 hydrophones (including four 4-element, three-dimensional arrays) between the VENUS coastal observatory in the Salish Sea and the NEPTUNE offshore deep-sea observatory in the Northeast Pacific Ocean. The data, streamed in quasi-real-time to ONC’s web data portal, offer a window on a number of different environments, from the busy, shallow waters of the Salish Sea to the 2200 m of depth of the Endeavour hydrothermal-vent field. This presentation gathers highlights from the latest research utilizing ONC’s acoustic infrastructure and data, ranging from ambient noise to hydrothermal-vent soundscapes, seismic events, bioacoustics, and signal processing applications such as source localization.

Blue Infrastructures: An Exploration of Oceanic Networks and Urban–Industrial–Energy Interactions in the Gulf of Mexico

Urban infrastructures serve as the backbone of modern economies, mediating global exchanges and responding to urban demands. Yet, our comprehension of these complex structures, particularly within diverse socio-political terrain, remains fragmented. In bridging this knowledge gap, this study delves into “boundary objects”—entities enabling diverse stakeholders to collaborate without a comprehensive consensus. Central to our investigation is the hypothesis that oceanic infrastructural developments are instrumental in molding the interface of urban, industrial, and energy sectors within marine contexts. Our lens is directed at the Gulf of Mexico, which is distinguished by its industrial depth and expansive marine grid. We highlight the Gulf Intracoastal Waterway’s (GIWW) paramount role in regional movement and the ecological facets of practices such as dredging, which is vital for transport and coastal conservation. A striking revelation of our study is the transformation of offshore structures in the Gulf into vibrant marine habitats. Emphasizing the intertwined nature of marine infrastructures, we denote oceans as pivotal platforms for impending urban expansion, especially as land resources wane. Our research aspires to validate the role played by oceans as a nexus in the urban–industrial–energy fusion.

Energy aware multilevel clustering scheme with Wake-Up Sleep Algorithm in underwater wireless sensor networks

For a wide range of reasons, researchers are interested in underwater wireless sensor networks (UWSNs). These include water quality and environment monitoring, disaster and earthquake prediction, surveillance by the military, and underwater navigation. Nevertheless, there are a lot of drawbacks and difficulties that come with the aquatic medium, including a high multipath delay, high levels of interference and noise, a harsh atmosphere, poor bandwidth, and short battery life for the sensor nodes. Yet, there are several obstacles to the successful deployment of underwater wireless sensor networks. The issue of sensor node energy depletion is the main cause of concern in the underwater sensor network. These problems require the use of good research methodologies and strategies to solve them. In this study, an Energy-Aware Multilevel Clustering with Wake-up Sleep Algorithm is developed to prolong the lifespan of the underwater wireless sensor network. The oceanic network region is thought to be a series of multi-level, 3D cylinders. High water pressure directed at the sea floor creates communication problems that are resolved by many layers of differing heights. The effectiveness of the suggested method is demonstrated by simulations, which demonstrate that it performs better in terms of an extended network lifespan, average residual energy, and many more factors. In comparison to the results of the simulation with current ones, the network lifespan has significantly increased.

Seasonal and diel patterns in Pacific white‐sided dolphin (Lagenorhynchus obliquidens) pulsed calls near Barkley Canyon

AbstractEvaluation of temporal patterns in offshore marine mammal activity through visual data collection can be impaired by light and weather conditions and the cost of ship time. The conditions‐independence and cost‐efficacy of acoustic data collection make it popular for researching the temporal patterns of wild dolphins. However, Pacific white‐sided dolphins (PWSDs) north of Southern California remain under‐researched. This study evaluates diel and seasonal patterns in PWSD communication signals detected in 480 days of near‐continuous passive acoustic data collected over 20 months from the Barkley Canyon node of Ocean Networks Canada's NEPTUNE observatory, offshore Vancouver Island, British Columbia, Canada. In this study, a random forest classifier is used to identify PWSD pulsed calls and false positives are manually removed. The resulting acoustic presence‐absence data set is evaluated for seasonal and diel patterns using generalized additive mixed models, considering masking effects from ambient noise. PWSDs are found to be vocally active during all diel periods year‐round, with high summer and low spring activity. Seasonally dependent diel patterns are identified, with PWSD pulsed calls exhibiting no diel pattern in spring, a slight increase in vocal activity during dusk and night in fall and winter, and a notable increase during night and dawn in summer.

Omnidirectional water wave-driven triboelectric net-zero power smart ocean network: An advanced hardware solution to long-distance target detection

Collecting ocean energy to build a zero-power smart ocean network that integrates energy harvesting and application is of great significance for achieving the strategy of marine power. This demands a hardware solution with simple structure, high energy efficiency, and high resolving ability. Herein, we proposed a simple fully symmetric triboelectric nanogenerator (FS-TENG) for efficient collection of omnidirectional wave energy without dead spot, based on the 360 degrees of freedom of inertial ball and the simplified double-layer electrode structure responding to arbitrary triggers. Employing the Maxwell’s displacement current generated by FS-TENG, power-free underwater wireless detection was achieved to sense the long-distance (220 m) target in water, which set a new record for triboelectric nanogenerator (TENG) based contactless sensing. The detection strategy is an effective method for marine data acquisition to realize intelligent ocean management demonstrating applications such as noninvasive inspection of pipeline difficult to reach for in-pipe robot, navigation and berthing for ship in need according its dimension, and sensing water level changes without moving part. The work builds a net-zero power smart ocean network based on TENG, providing new ideas for sustainable ocean development.