(NaturalNews) Noise on the oceans has increased considerably since the 1960s. A 2006 study at Scripps Institution of Oceanography at the University of California, San Diego, showed that our underwater world has become a much noisier place than it once was. This noise could be killing ocean life.
The study compared acoustic data recorded by the US Navy in the same area of San Nicolas Island west of San Diego. Results showed that noise levels were 10 to 12 decibels higher in 2003-2004 than in 1964-1966,an increase of three decibels per decade.
This noise may be caused by ships, wind farms, drilling, pile driving, construction and seismic testing.
Marine life uses sounds from the natural environment for many aspects of life. Although marine animals use vision they also gain auditory information that is far more extensive than the visual sense. In fact, notes Dr. Popper of the University of Maryland, sounds provide marine animals with a three dimensional view of the world.
An article titled `Human-Generated Sounds May Be Killing Fish` reported that invasive human noise could alter behavior patterns and mean the difference between life and death for marine animals. Marine animals can suffer from stress or become disoriented due to noise pollution in the same way as humans or land animals.
The construction and maintenance of coral reefs depends on sound. Dutch researchers in Curacao found that coral larvae use sound to establish a colony. Coral reefs support a vast range of aquatic life. Now threatened by global warming, storms and ocean acidification, the effect of noise pollution caused by humans on coral reefs may be yet another crucial deciding factor in the life and death equation of ocean life.
Dr. Steve Simpson of the University of Bristol conducted research into baby reef fish and discovered that baby reef fish use sounds made by fish, shrimp and sea urchins to find coral reefs. This fish needs coral reefs in order to thrive.
But in the crucial early hours of life, exposure to artificial noise can cause this fish to make the wrong choices. Notes Dr. Simpson, ``If fish accidentally learn to follow the wrong sounds, they could end up stuck next to a construction site or follow a ship back out to sea.``
In `Lonely Whales Shout to Overcome Noise` North American right whales are reported to battle environmental noise by raising their voices just like people in a noisy bar. Susan Parks, assistant professor of acoustics, Penn State, says that in a noisy ocean, it is ``critical for successful communication in an increasingly noisy ocean`` to be able to alter sound production.
Whales produce `upcalls` when they are alone or when they are joining a group of whales. Parks` study determined that an increase in background ocean noise due to commercial shipping has produced a corresponding increase in whale upcalls.
But there are considerable risks for the whales in increasing their upcalls. They expend more energy and alter their signals and the information contained in a signal, and they increase the risk of predators. Also, increased ocean noise lowers the communication range; feeding and mating could shrink, and stress levels could rise.
``It may be appropriate to move shipping lanes away from areas where there are concentrations of marine animals,`` a researcher noted. ``The impact of ocean noise pollution may be minimized by diminishing the noise source or by separating the noise from things that are sensitive to it.``