Learnings

Outcomes

2024/2025

In 2024/2025, significant progress was made across multiple work streams. Under Work Stream 1, the SCAMPI device was successfully designed, constructed, and rigorously tested (Deliverable 1 and 2), providing a robust platform for controlled ecological experiments replicating electromagnetic fields generated by HVDC cables. Work Stream 2 culminated in the completion of a comprehensive literature review (Deliverable 3), which offered an in-depth overview of existing knowledge on EMF impacts and identified key gaps to guide experimental focus. Work Stream 4 saw the successful completion of initial exposure experiments on three functionally distinct benthic species, exposing them to four levels of EMF derived from real-world HVDC cable measurements (Deliverable 7). These experiments yielded valuable insights into the behavioural and physiological responses of marine organisms to EMF exposure. Additionally, Deliverable 4 a presentation summarising experimental plan and experimental designs was delivered under Work Stream 4, communicating project progress and future directions to National Grid.

Recommendations for further work

Not Applicable

Lessons Learnt

2024/2025

Throughout the experimental phases and the development of SCAMPI, we gained valuable insights into key modifications and adaptations that can inform future experiments and projects. For example, we learned how to model EMF exposures based on real-world cable data, enabling us to replicate realistic load patterns for different experimental designs. We also developed methods to adapt the experimental design of the SCAMPI system for both AC and DC EMF regimes, expanding the range of cable types that can be simulated. Additionally, we refined the experimental setup to accommodate the behavioural and physiological needs of different marine species, allowing for more targeted and ecologically relevant assessments. These lessons have significantly enhanced our ability to broaden the scope, precision, and ecological realism of future EMF impact studies.

Initially, there was uncertainty around how to define and calculate the electromagnetic (EMF) load for Deliverable 8, particularly concerning the structure and duration of on/off exposure cycles. Rather than implementing continuously fluctuating EMF levels, which would complicate comparisons with Deliverable 7, we aimed to keep the total EMF exposure comparable involving continuous 5-day exposure. To achieve this, we analysed real-world subsea cable operational data, identifying peak and low current periods to represent realistic ‘on’ and ‘off’ phases. These were used to construct a binary EMF exposure cycle with controlled cumulative load, enabling ecologically relevant simulations while maintaining consistency with previous datasets. This approach not only improved experimental realism but also provided a validated framework for designing future studies involving temporally dynamic but quantitatively comparable EMF exposures.

Modelling the required electromagnetic fields and setting up experiments was initially a time-intensive process, particularly due to the need for accurate field modelling and system configuration tailored to each specific test scenario. Simulating realistic subsea cable conditions also demands substantial preparation and ongoing monitoring. However, through gained experience from Deliverable 7 and 8, we have been able to streamline and optimise this workflow. By testing shorter experimental times, overlapping experimental runs and pre-scheduling modelling and setup tasks, we have significantly increased efficiency and experimental throughput. Importantly, the design and implementation of each experiment is a collaborative effort. A key lesson learned is that successful experimental design relies on collaborative, interdisciplinary planning. Coordination between ecology, physics, and engineering teams is essential to select appropriate EMF parameters, biological endpoints, and environmental conditions that ensure ecological relevance. This group decision-making approach has been critical to improving both the quality and scalability of our experiments for future projects.

Through Deliverable 7, we have learned how to effectively characterise the isolated effects of EMF exposure, identifying changes in parameters such as mean and median burial depth, while noting that respiration and maximum burial depth and surface boundary roughness remained unaffected. This experience has provided us with a clearer understanding of which biological responses are most sensitive to EMF and how to design experiments to detect subtle changes. These insights now position us to inform future projects by enabling the investigation of more complex, multi-stressor scenarios such as the combined effects of EMF with underwater sound, heavy metal exposure from cable materials, and nutrient disruption during seabed installation. This progression supports the development of more ecologically relevant studies, and a deeper understanding of how multiple environmental pressures interact to affect marine organisms.

Dissemination

2024/2025

While no dissemination events have taken place to date, two external engagements have been confirmed for 2025:

Jicable HVDC 2025 (October 20–22, 2025): An abstract has been accepted for poster presentation titled “SCAMPI: A Tool for Generating HVDC Magnetic Fields and Experimental Planning for Benthic Invertebrate Impact Studies.” The poster will focus on the development and modelling of the SCAMPI (Synthetic Cable for the Assessment of Marine Power Impacts) device, designed to replicate realistic magnetic field distributions produced by HVDC subsea cables. The work highlights SCAMPI’s capability to provide a controlled and thermally stable experimental environment for studying electromagnetic impacts on marine life. The poster also outlines recommended experimental methods and planning guidance for benthic invertebrate studies, forming a foundation for future biological impact assessments. A full conference paper is planned for submission in conjunction with this presentation.

 IASWS 2025 – International Association for Sediment Water Science (June 30–July 4, 2025):

“Impacts of Electromagnetic Fields from Offshore Subsea Cables on Benthic Marine Ecosystems.”

 This presentation will focus on experimental investigations into how anthropogenic electromagnetic fields (EMFs) generated by offshore subsea cables influence benthic ecosystem functioning. Specifically, it addresses the role of EMF intensity, waveform type (DC vs AC), and exposure regime (continuous vs intermittent) in shaping key ecological processes such as total oxygen uptake (TOU) and bioturbation (sediment reworking and bioirrigation) in selected benthic invertebrate species. The work uses ecologically relevant EMF values based on field-derived data to inform experimental design.