• The exact location has not been revealed but signals can reach submarines across vast distances, researchers say
• A joint experiment with Russia confirmed a ‘ping’ from the facility can also travel effectively underground

By Stephen Chen in Beijing

Published: 10:30pm, 2 Dec, 2021

The biggest antenna on the planet is up and running in central China, opening up long-distance communications with submarines as well as civilian applications, according to engineers and scientists involved in the project.

The exact location of the facility has not been revealed, but is believed to be somewhere in the Dabie Mountains, a protected natural reserve straddling Hubei, Anhui and Henan provinces.

From space, the antenna, which is formed by a network of cables and pylons much like those in ordinary power lines, would look like a giant cross more than 100km (62 miles) long and wide.

But at the ends of those lines, copper nodes are fixed deeply into thick granite. Two powerful underground transmitters – capable of working independently in case one is damaged – charge one megawatt of electrical current and turn the Earth into a giant radio station.

According to a paper published in last month’s Chinese Journal of Ship Research, receiving devices planted 200 metres (700 feet) below the surface on the sea floor can effortlessly pick up signals from the giant antenna 1,300km (800 miles) away – a range that covers the Korean peninsula, Japan, Taiwan and the South China Sea.

The project’s lead engineer Zha Ming and his colleagues, from the Wuhan Maritime Communication Research Institute, said the facility was designed to maintain underwater communications over a total range of 3,000km (1,9000 miles) – enough to reach Guam, the biggest US military base in the western Pacific Ocean.

The extremely low frequency (ELF) facility can generate electromagnetic waves from 0.1 to 300Hz. These radio waves can travel great distances both underwater and below ground.

Read more at: https://www.scmp.com/news/china/science/article/3158162/china-antenna-turns-earth-giant-radio-station-signals-reaching

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Highlights

• In a bundled DC cable, closer cable cores reduced the emitted DC magnetic field (DC-MF) intensity.

• As a cable’s burial depth increased, the intensity of DC-MF at the seabed surface decreased.

• Buried cables still present a DC-MF at intensities perceivable to some receptive species.

• Variable burial depth along a cable route will present a variable EMF to receptive species.

• An animal’s proximity to a cable (buried or not) influences their exposure to the EMF.

Abstract

The expanding marine renewable energy industry will increase the prevalence of electromagnetic fields (EMFs) from power cables in coastal waters. Assessments of environmental impacts are required within licensing/permitting processes and increased prevalence of cables will increase questions concerning EMF emissions and potential cumulative impacts. It is presumed that protecting a cable by burial, may also mitigate EMF emissions and potential impacts on species. Focussing on a bundled high voltage direct current (HVDC) transmission cable, we use computational and interpretive models to explore the influence of cable properties and burial depth on the DC magnetic field (DC-MF) potentially encountered by receptive species. Greater cable pair separation increased the deviations from the geomagnetic field and while deeper burial reduced the deviations, the DC-MF was present at intensities perceivable by receptive species. An animal moving along a cable route may be exposed to variable EMFs due to varied burial depth and that combined with an animal’s position in the water column determines the distance from source and EMF exposure. Modelling contextually realistic scenarios would improve assessments of potential effects. We suggest developers and cable industries make cable properties and energy transmission data available, enabling realistic modelling and environmental assessment supporting future developments.

https://www.sciencedirect.com/science/article/abs/pii/S0960148121007175?via%3Dihub

The post A modelling evaluation of electromagnetic fields emitted by buried subsea power cables and encountered by marine animals: Considerations for marine renewable energy development appeared first on EMFSA.

Video abstract

The post Map-like use of Earth’s magnetic field in sharks appeared first on EMFSA.

https://doi.org/10.1016/j.marenvres.2020.104958

Abstract

The goal of clean renewable energy production has promoted the large-scale deployment of marine renewable energy devices, and their associated submarine cable network. Power cables produce both electric and magnetic fields that raise environmental concerns as many marine organisms have magneto and electroreception abilities used for vital purposes. Magnetic and electric fields’ intensities decrease with distance away from the cable. Accordingly, the benthic and the sedimentary compartments are exposed to the highest field values. Although marine invertebrate species are the major fauna of these potentially exposed areas, they have so far received little attention. We provide extensive background knowledge on natural and anthropogenic marine sources of magnetic and electric fields. We then compile evidence for magneto- and electro-sensitivity in marine invertebrates and further highlight what is currently known about their interactions with artificial sources of magnetic and electric fields. Finally we discuss the main gaps and future challenges that require further investigation.

The post A current synthesis on the effects of electric and magnetic fields emitted by submarine power cables on invertebrates appeared first on EMFSA.

Abstract

Electromagnetic surveys generate electromagnetic fields to map petroleum deposits under the seabed with unknown consequences for marine animals. The electric and magnetic fields induced by electromagnetic surveys can be detected by many marine animals, and the generated fields may potentially affect the behavior of perceptive animals. Animals using magnetic cues for migration or local orientation, especially during a restricted time-window, risk being affected by electromagnetic surveys. In electrosensitive animals, anthropogenic electric fields could disrupt a range of behaviors. The lack of studies on effects of the electromagnetic fields induced by electromagnetic surveys on the behavior of magneto- and electrosensitive animals is a reason for concern. Here, we review the use of electric and magnetic fields among marine animals, present data on survey generated and natural electromagnetic fields, and discuss potential effects of electromagnetic surveys on the behavior of marine animals.

https://www.researchgate.net/publication/338814097_Electric_and_magnetic_senses_in_marine_animals_and_potential_behavioral_effects_of_electromagnetic_surveys

The post Electric and magnetic senses in marine animals, and potential behavioral effects of electromagnetic surveys appeared first on EMFSA.