Newsletter 3

Hello everyone!

Here we are with the third periodic update on our project. We are making great progress and would like to share the latest news with you.

Underwater image of the cable connected to the system

DAS system successfully operating 

Since October 2025, the DAS prototype has been successfully operating at the CNR-IAS Experimental Marine Station in the Port of Genoa, where it continuously monitors the behavior of a submerged medium-voltage cable. Developed by the University of Alcalá, the DAS interrogator simultaneously measures strain in three optical fibers embedded within a telecom-grade 12-fiber cable installed at the core of the power cable. This technology provides detailed information about dynamic cable bending caused by environmental conditions or human activity.

To better understand how the cable evolves over time, an active monitoring campaign has been carried out since October 2025 and is still ongoing. During this period, controlled impacts and curvature variations have been intentionally applied to the cable, while the DAS system records its dynamic response with high sensitivity. The goal is to investigate how the gradual accumulation of biofouling—marine organisms growing on the cable surface—affects its mechanical behavior.

So far, the monitoring campaign has proven highly successful, accurately detecting induced events and revealing subtle changes in cable dynamics. A thorough analysis of the data collected over the testing period is expected to provide important insights into the influence of biofouling growth on cable performance. Beyond this specific experiment, the results will contribute to validating distributed fiber-optic sensing as an innovative, efficient, and scalable technology for the future monitoring of offshore power transmission infrastructure.

Per-fiber strain detected with the DAS system and curvature reconstruction of the medium-voltage cable under the applied controlled stimulus.

Biofouling on Submarine Cables

Approximately three years ago, selected cable sections were installed at the W1M3A site as part of SEASNAKE+ experimental activities. After nearly three years of exposure to natural conditions, these samples now offer a clear picture of early-stage biofouling and ecological colonization processes on cable materials.

Within SEASNAKE+, activities are not limited to the development of innovative technologies for submarine cable systems but also address their interaction with the marine environment. In this context, the cable samples deployed on the W1M3A marine infrastructure provide a valuable case study for understanding how these systems evolve once installed at sea.

The six cable triplets installed along the submerged structure of the W1M3A spar buoy reveal a striking depth-driven evolution of marine fouling communities. Although all depths are exposed to a continuous supply of larvae and propagules originating from the buoy itself, the structure and composition of the fouling assemblages change progressively with increasing depth. Across the entire depth range, the fouling communities are composed of a combination of organisms, including filamentous algae, hydroids, bryozoans, colonial tunicates, mussels, and other hard macrofouling species. Filamentous algae are most abundant in the shallower sections, while hydroids form the dominant filamentous “hairy” component throughout much of the structure. Encrusting and bushy colonies of bryozoans and tunicates contribute to the increasing complexity of the assemblages, alongside mussels (Mytilus spp.) and hard fouling organisms such as stalked barnacles, belonging to the genus Lepas. Overall, the observations highlight a clear ecological transition from diverse, mixed shallow-water communities to highly structured and mature deep-water assemblages, demonstrating how depth strongly influences the organization and development of marine fouling on offshore infrastructure. 

This aspect is highly relevant within SEASNAKE+, as the project aims not only to improve the performance and resilience of subsea cable technologies but also to better understand and potentially mitigate their environmental footprint. Studying colonization processes contributes to a more comprehensive evaluation of the ecological implications of offshore infrastructures. 

The W1M3A infrastructure thus serves as a real-world test site within SEASNAKE+, enabling researchers to link engineering solutions with environmental monitoring. These findings support the project’s broader objective: advancing sustainable and environmentally aware approaches to underwater cable system design and deployment.

Simulation of cable deformations and biofouling under realistic sea condition

As part of the project’s workpackage 4, recent numerical studies have focused on anticipating and mapping the complex deformations experienced by power cables connected to floating structures. To achieve this, the open-source FRyDoM API was successfully deployed by the D-ICE team to simulate these dynamic behaviors under realistic sea states.

The initial phase focused on benchmarking the numerical model developed in FRyDoM against real bending deformation tests. Conducted by UGE (Université Gustave Eiffel) on a medium-voltage cable section, the physical trials confirmed the model's accuracy, showing an excellent correlation with experimental results (curvature discrepancy under 5%).

Following this validation, the model was deployed on a larger scale for umbilical integration studies on various floating platforms subjected to a realistic marine environment (irregular waves, turbulent wind). The simulations were notably tested on the ODAS Italia 1 oceanographic buoy (operated by the CNR) as well as the VolturnUS-S semi-submersible platform (which supports the IEA 15 MW reference wind turbine), evaluating different cable line configurations and geometries.

By testing the cable's behavior under stochastic sea states, this approach provides crucial insights for umbilical design. It allows for the precise location of line sections subjected to the highest curvatures and geometric variations induced by the platform's motions. By quantifying the frequency and amplitude of the deformation cycles experienced by the cable during long-term simulations, the model provides fundamental input data for future structural integrity studies and fatigue life prediction.

Crucially for the SEASNAKE+ objectives, the tool integrates the impact of biofouling (biological colonization by marine fauna and flora) on cable dynamics. Simulations under realistic sea conditions made it possible to observe how the increased weight of the line and the modification of its hydrodynamic drag influence its deformations. Notably, marine growth shifts and accentuates deformation cycles toward localized areas near the seabed and anchor points—a vital finding for optimizing long-term operations and maintenance (O&M) strategies.

Upper left: entrance to the pavilion at World Ocean Day in Genoa, Lower left: stand of the Western Mediterranean Sea regional facility, Right: presenting the project to the public.

World Ocean Day in Genoa

From 6 to 8 June 2026, Genoa hosted the celebrations for World Oceans Day, promoted by the Italian National Institute of Geophysics and Volcanology (INGV) under the theme “Know, Understand, Coexist”. The initiative brought together scientific, educational, and cultural activities aimed at raising public awareness of the ocean’s essential role in life on Earth. In this vibrant and engaging context, CNR presented the SEASNAKE+ project, sharing its objectives, ongoing activities, and future perspectives with a broad audience.

The event featured exhibitions, laboratories, talks, and interactive installations designed to engage visitors of all ages, fostering a deeper understanding of marine environments and the challenges they face. Participation was diverse and enthusiastic, including families, students, stakeholders, researchers, and ocean enthusiasts, reflecting a growing public interest in marine conservation and sustainability.

On our stand, we introduced the SEASNAKE+ project and highlighted the importance of scientific research in monitoring and protecting marine ecosystems. To make our work more tangible and engaging, we also brought physical samples: visitors had the opportunity to touch and closely examine sections of submarine cables and protective coatings, gaining a direct, hands-on understanding of the materials and technologies involved. 

A key aspect of the event was direct interaction with visitors, who could ask questions, explore specific topics, and better understand the impact and relevance of scientific research. This exchange proved valuable not only for the public but also for us as researchers, offering insights into how to further improve the accessibility and effectiveness of scientific communication.