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How do subsea cables affect electromagnetic-sensitive marine species?

Anthropogenic activity is changing the natural electromagnetic environment. This may impact many marine species that have adapted to use electric and magnetic cues in essential aspects of their life cycle. The installation of underwater cables in coastal and offshore waters, to support offshore generation of renewable energy and transmission networks, is increasing globally. These cables emit electromagnetic fields (EMFs) that can interact with natural geomagnetic EMFs, potentially disrupting cues used by electromagnetic-sensitive species. A recent interdisciplinary study explored how two such marine species, the little skate (Leucoraja erinacea) and the American lobster (Homarus americanus), react in the presence of a real subsea EMF-emitting cable. 5th October 2020 / Issue 549 Sensory abilities of marine species are being increasingly disrupted by human activity, such as noise and light pollution or the alteration of the marine environment via installation of infrastructure. Many marine Subscribe to free species rely upon natural EMFs to detect prey, avoid predators, find mates, orientate and migrate. Natural bi-weekly News Alert. EMFs interact with those emitted by anthropogenic sources such as ships, bridges and subsea cables; these are quantifiable at a similar magnitude to the background geomagnetic field1 and may interfere Source: with, or mask, vital cues for elecromagnetic-sensitive species. Hutchison, Z. L., Gill, A. B., Sigray, P., He, This risk is becoming more pressing as global demand increases for subsea cables to support electrical H. and King J. W. (2020) Anthropogenic power generation, SMART grids and telecommunications. Given international commitments to increase electromagnetic fields (EMF) influence production of offshore and floating marine renewable energy, and the associated increase in electricity the behaviour of bottom-dwelling transmission cables, there is a greater need to understand and potentially mitigate the effects of human- marine species. Scientific Reports 10 driven EMF emission on marine species and ecosystems. (4219). European companies represent 90% of the offshore wind power global market2, and the EU is committed Contact: to increasing its investments into offshore renewables as part of the European Green Deal. The EU aims [email protected], to ensure that 30% of electricity demand is provided by offshore wind by 2050, as part of efforts to reach [email protected]. climate neutrality by the same year.

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How do subsea cables affect electromagnetic-sensitive marine species? (continued)

Subsea cables are most commonly laid upon, or buried in the seabed, and so are likely to be Read more about: encountered by bottom-dwelling EM-sensitive organisms. A new study explored two such species of Emerging risks, Marine and ecological and commercial importance: the little skate (Leucoraja erinacea) and the American lobster coastal, Risk assessment (Homarus americanus). The researchers used in situ treatment and control enclosures, and a tagging system that allowed fine-scale tracking of individual animal positions and movement. They assessed The contents and views included whether each species adjusted their behaviour in the treatment enclosures compared to the control. in Science for Environment Policy The treatment enclosure3 was exposed to the EMF emitted by a subsea high-voltage direct current are based on independent, peer- (HVDC) transmission cable for domestic energy supply4. The local geomagnetic field and the electric reviewed research and do not necessarily reflect the position of and magnetic fields emitted by the cable were simultaneously quantified using novel, highly sensitive the European Commission. Please bespoke equipment to characterise the EM-environment. note that this article is a summary The lobster and skate studies took place in August to September and September to October 2016, of only one study. Other studies may come to other conclusions. respectively. The skates were notably affected by the EMF emissions, with a marked rise in exploratory and foraging behaviour, while the lobsters displayed a more subtle exploratory response. Skates travelled almost twice as far in the treatment enclosure compared to the control enclosure; moved To cite this article/service: “Science for Environment Policy”: at differing speeds; made a higher proportion of large turns (170o–180o); and stayed closer to the European Commission DG seabed. They also appeared to rest less frequently. Environment News Alert Lobsters, meanwhile, showed similar behaviour in the treatment enclosure in terms of distance Service, edited by SCU, The University of the travelled and speed, but displayed fewer large turns, and stayed closer to the seabed. They explored West of England, Bristol.. the seabed more, presumed to be foraging or searching for burrows. The treatment enclosure was designed so that the EMF-emitting cable created a gradient of EMF, Subscribe to free forming zones of ‘higher’ and ‘lower’ EMF emission. The researchers also explored which zones the bi-weekly News Alert. lobsters and skates occupied, finding that the animals used the full extent of the enclosure but with some differences in behaviour. Skates spent more time in the high-EMF zone, also travelling further and performing more large turns in this region, while lobsters showed no notable difference. Overall, the study shows that electro- and magneto-sensitive species display observable behavioural 1. Thomsen, F., Gill, A.B., Kosecka, M., Andersson, M.H., Andre M., differences in the presence of an EMF-emitting HVDC electricity cable. Furthermore, the study highlighted Degraer, S., Folegot T., Gabriel, J., Judd, A., Neumann, T., Norro, A., Risch D., Sigray, P., Wood, D. and Wilson, B. (2015) MaRVEN the need to directly measure the electric and magnetic fields in situ in order to validate EMF modelling. – Study of the environmental impacts of noise, vibrations and The ecological insight from behavioural studies, integrated with direct measurement and modelling of electromagnetic emissions from marine renewables – Final Report to European Commission, Directorate-General for the EMF from subsea cables, will be important for considering future deployments, say the researchers Research and Innovation. RTD-K3-2012-MRE. — but further research is needed to define the electromagnetic environment and species’ sensitivity 2. European Commission (2020) Onshore and offshore wind: https://ec.europa.eu/energy/topics/renewable-energy/onshore- thresholds. These results have helped define research needs to inform management on anthropogenic and-offshore-wind_en EMFs and their potential impact on electromagnetic--sensitive animals in the marine environment. 3. Recent research conducted on electromagnetic field and lobsters has used smaller enclosures: Taormina B. et al. (2020) Impact of magnetic fields generated by AC/DC submarine power cables on the behavior of juvenile European lobster (Homarus gammarus). Aquat Toxicol. 220: 105401: https://pubmed.ncbi.nlm.nih.gov/31924586/ 4. The peak magnetic field at the base of the treatment enclosure was 65.3 microtesla (μT) (max), while animals in the control enclosure were exposed to the ambient geomagnetic Environment field (51.3 µT).