Animal magnetism: how wave, tidal energy devices affect sea life

What does a shark, sea turtle or crab do when it encounters the electromagnetic field of a wave power cable? Government scientists are on the case.
Written by Melissa Mahony, Contributor

As more projects go to sea for renewable energy sources, questions of how wave and tidal power devices might affect marine life are bound to surface. This week at the "Oceans 2010" conference in Seattle, scientists from the Pacific Northwest National Laboratory (PNNL) are discussing how they're looking into some of them.

I've written earlier about efforts to see whether noise might safely dissuade whales from swimming into wave power buoys off Oregon's coast. The focus of these researchers is electromagnetic fields.

Many marine species—sea turtles, crabs, sharks, skates, salmon and other fish—rely on Earth's magnetic fields for migrating or searching for food. The many iterations of wave, tidal and hydrokinetic power devices, and the cables that bring the electricity they generate to shore, produce similar electromagnetic fields.

PNNL's Jeff Ward, a marine ecologist, says in a statement:

We really don't know if the animals will be affected or not. There's surprisingly little comprehensive research to say for sure.

Much of the data that does exist has been conducted in other parts of the world, such as Sweden, with other sets of sea creatures. To determine how magnetic fields influence animals in American waters, the scientists will place two Helmholtz coils (right), consisting of 200 pounds of copper each, next to aquariums holding different marine species. In their two-year long study, which began over the summer, they will turn the coils on and off at varying intervals and strengths, and observe how the species react.

According to the researchers, the 0.1 to 3 milliTeslas of magnetic flux that the coils can produce is relatively small compared to other studies on electromagnetic fields and sea life. How this compares to fields given off by the energy devices was not given, but understanding the influence of even slight changes in electromagnetic fields on the animals is important. Some of the circumstances and behaviors the study will investigate are:

  • The ability of juvenile Coho salmon to spot and avoid predators
  • The Dungeness crab's ability to quickly flick its antennules to detect odors
  • Whether the electromagnetic fields repel or attract certain species
  • How hydrokinetic devices in rivers affect freshwater wildlife (Oak Ridge National Laboratory)
  • The affect of electromagnetic fields on crabs (Northwest National Marine Renewable Energy Center)

If the species studied do exhibit changes in their behavior, future research may expand out of the lab and into the sea where pilot projects are underway.

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Images: Wikipedia, PNNL and ORNL

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