Wind farms may be a vital source of green energy, but new research shows that the construction of off-shore wind farms could potentially be damaging the hearing of harbour seals and other marine life.
Researchers at St. Andrews University in Scotland believe that there is cause for concern that human building operations in our coastal waters, for example the pile driving process that hammers the foundation posts for wind turbines into the sea bed, could be damaging the hearing of marine mammals to an extent we hadn’t previously guessed at.
Scientists from the university’s sea mammal research unit came to this conclusion after observing 24 harbour seals and their behavior while offshore wind turbines were being installed in an area known as the Wash, on the east coast of England, in 2012. They did this by attaching (harmless) GPS data loggers to the seals and following the data that was sent back as the seals rested and as they went about their hunting activities.
They then combined the data they were gathering with information on where exactly the pile driving for installation of wind turbines was taking place. By knowing both the seals’ location and the location of the pile driving, the researchers could create a model that would tell them roughly what noise levels the seals were being exposed to and at what threshold, ascertained by other studies, the seals might be being exposed to damaging levels of noise.
The study, which is published this month in the British Ecological Society’s Journal of Applied Ecology, found that around half of the tagged seals were venturing into waters near to the construction areas and were probably being exposed to noise levels that were above the hearing damage threshold, meaning that in all likelihood, those seals are suffering hearing damage from our activities.
What’s particularly concerning about this is that there’s little research on how these loud, rapid and pulsing sounds might impact other marine animals, and indeed, how far that sound might carry–the researchers here were only looking at the immediate areas surrounding the construction sites, but if these particular sounds carry much further, more marine mammals may be at risk.
Lead researcher in this study Gordon Hastie is quoted as saying:
“These are some of the most powerful man-made sounds produced underwater, noise capable of travelling large distances underwater. Like most marine mammals, harbour seals have very sensitive underwater hearing at a much broader range of frequencies than humans. Our predictions highlight that seals may routinely be exposed to potentially hazardous levels of underwater noise during pile driving, with potential implications for the conservation status of some populations.”
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Seal pup image via Shutterstock.