Do magnetic fields related to submarine power cables affect the functioning of a common bivalve?

Exploring the impact of magnetic fields related to submarine power cables on the American mud crab Rhithropanopeus harrisii: A behavioural and physiological perspective

The number of submarine cables in marine environment is increasing. Thus, marine organisms, especially benthic invertebrates are exposed to magnetic fields generated by those cables. The aim of the study was to determine the effect of static magnetic field (SMF) and electromagnetic field (EMF) on the behaviour and physiology of Rhithropanopeus harrisii during a series of laboratory experiments. Neither SMF nor EMF significantly affected oxygen consumption rate, ammonia excretion rate and haemolymph osmotic concentration after 8-day exposure. In experiment related to spatial preferences crabs showed a clear attraction to EMF and were more active in EMF than in the geomagnetic field. In small areas without additional cues (locomotor activity experiment) EMF did not elicit changes in activity, whereas in experiment on conspecific behaviour crabs were more active and socially interactive. In SMF neither attraction nor avoidance behaviour was observed but decrease in activity and less interaction between individuals was noted.

Assessing the effects of electromagnetic fields generated by submarine power cables on the soft-bottom community: An ecological in-situ study

This study represents the first in situ investigation into the effects of magnetic fields (MFs) on soft-bottom macrofauna communities, laying the groundwork for further studies to better understand their potential consequences on marine ecosystems. Conducted in the Natural Park of the Strait (Southern Iberian Peninsula), the study measured MFs generated by HVAC cables and assessed their impact on soft-bottom macrofauna communities by comparing areas exposed to MFs with two control areas at different depths. Measured MF intensities were relatively low, with a maximum deviation from background levels of 34 nT near the cable, decreasing to 1 nT at 250 m distance. These intensities are considerably lower than those typically used in laboratory experiments inducing physiological effects (0.1-30 mT). Results revealed an increasing pattern of species richness (S) with depth, associated with sediment stability and different sediment characteristics. While analyses did not show significant effects of the magnetic field on macrobenthic communities overall, some indications were observed, such as decreased species richness at the deepest station and community homogenization across depths in the cable area compared to control zones. However, the varying patterns observed across different sites and depths necessitate further investigation, particularly considering the differences in MF intensities between field settings and controlled laboratory environments.

Effect of electromagnetic fields from renewable energy subsea power cables on righting reflex and physiological response of coastal invertebrates

Offshore renewables are expanding, yet more information is required to understand their possible impacts on the environment. Little is known about the effects of Electromagnetic Fields (EMF) from subsea power cables on marine life. This study simulated an EMF of 500 μT, as modelled for an export cable over a rocky shore, where the industry standard cable burial would not be possible. Righting reflex, refractive index of haemolymph/coelomic fluid, and total haemocyte/coelomocyte counts were measured for four coastal invertebrates (Asterias rubens, Echinus esculentus, Necora puber, and Littorina littorea). No significant differences were found in either behavioural or physiological responses. This was the first study to investigate EMF exposure on righting reflex, and the first ever EMF study on edible sea urchins and periwinkles, and only one of a couple for common starfish and velvet crabs. It therefore, provides valuable data for environmental impact assessments, marine spatial planning, and commercial fisheries.

Introducing energy into marine environments: A lab-scale static magnetic field submarine cable simulation and its effects on sperm and larval development on a reef forming serpulid

Non-chemical sources of anthropogenic environmental stress, such as artificial lights, noise and magnetic fields, are still an underestimate factor that may affect the wildlife. Marine environments are constantly subjected to these kinds of stress, especially nearby to urbanized coastal areas. In the present work, the effect of static magnetic fields, associated with submerged electric cables, was evaluated in gametes and early life stages of a serpulid polychaete, namely Ficopomatus enigmaticus. Specifically, biochemical/physiological impairments of sperm, fertilization rate inhibition and incorrect larval development were assessed. We evaluated differences between two selected magnetic field induction values (0.5 and 1 mT) along a range of exposure times (30 min-48 h), for a sound evaluation on this species. We found that a magnetic induction of 1 mT, a typical value that can be found at distance of tens of cm from a submerged cable, may be considered a biologically and ecologically relevant for sessile organisms and for coastal environments more generally. This value exerted statistically significant effects on membranes, DNA integrity, kinetic parameters and mitochondrial activity of sperm cells. Moreover, a significant reduction in fertilization rate was observed in sperm exposed to the same magnetic induction level (1 mT) for 3 h, compared to controls. Regarding early larval stages, 48-h exposure did not affect the correct development. Our results represent a starting point for a future focus of research on magnetic field effects on early life stages of aquatic invertebrates, using model species as representative for reef-forming/encrusting organisms and ecological indicators of soft sediment quality.