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- A mere half-century ago, the music of nature rang out
largely unmolested. Whales, dolphins, and turtles crooned their eerie songs
and distant galaxies spewed out their radio signals bearing information
from the big bang and the great beyond.
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- Not so today. In short order, mankind has raised such
a ruckus that if the planet were a party, Mother Nature would have to call
the cops.
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- The incessant chirp of radio waves from communications
satellites has grown so pervasive that astronomers claim it interferes
with their radio telescope observations. Marine biologists say the throb
of supertanker propellers creates such a din that whales, dolphins, and
other sea creatures are at risk.
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- "These things have gradually built up without people
taking too much interest in whether or not the noise is affecting the natural
system," says Sylvia Earle, the explorer in residence for that National
Geographic Society and an oceanographer. "To be so arrogant to think
that we can do anything with the skies above or the seas below without
studying the consequences is inexcusable."
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- To be sure, radio waves and sound waves are very different.
When radio astronomers refer to noise, they mean local radio interference
that blocks out signals from outer space. When marine biologists refer
to noise, they mean sound waves that physically vibrate and can even damage
living tissues but are not part of the electromagnetic spectrum like radio
waves.
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- Undersea Racket
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- Some marine biologists say that human noises under the
water - ranging from sonar blasts to the churning of enormous propellers
- can harm sea life.
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- But both types are symptoms of technological progress
and economic development.
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- In the seas, the size and tonnage of the world's merchant
fleet has skyrocketed to service growing global trade. This has led to
increases in shipping noise, particularly near big ports like San Francisco
and New York. While oil prospectors in the past drilled with maps and a
hunch, they now use high-tech airguns that blast sound waves deep into
the Earth to detect likely deposits of crude.
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- Navies around the world are developing deep ocean sonar
systems that broadcast sound waves in their search for submarines, often
in wavelengths used by whales for communication. Scientists have also set
up underwater "boomboxes" to gauge ocean temperatures and test
for global warming by measuring the speed of sound waves through seas.
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- "The issue is acute in the ocean because sound travels
better in water," says Joel Reynolds, director of the Natural Resource
Defense Council's (NRDC's) Marine Mammal Protection Project. "It's
not really a visual world, so animals have adapted to use of sound for
crucial tasks like identifying food sources...."
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- Some environmentalists believe mass whale beachings and
increased rates of marine mammal mortality are directly attributable to
louder oceans. Others worry that underwater noise is interfering with communications
of whales and other creatures in the same way that car horns hamper human
conversation.
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- According to the NRDC, the amount of ambient noise in
the ocean may have increased by 10 decibels - in other words, 10-fold -
between 1950 and 1975.
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- In the skies, new constellations of communications satellites
broadcast radio waves on frequencies very close to those used by big radio
telescopes to study distant galaxies. Dozens more of these satellites are
scheduled for launch as the demand for cell phones and global communications
increases.
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- Despite efforts by telecommunications companies to protect
bandwidths that hold crucial astronomical information, the volume of satellites
threatens to overwhelm astronomers. Such is the case with Motorola's Irridium
satellites. Signals from this global network allowing callers to phone
home from virtually any point on Earth bleeds into an observation bandwidth
for hydroxide molecules, a crucial in element in star formation.
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- "When a communications satellite passes overhead,
it can be like setting off dynamite in someone's living room," says
Seth Shostak, a radio astronomer with the Search for Extraterrestrial Intelligence
Institute. According to Mr. Shostak, the repetitive radio signals from
satellites and space probes mimic what scientists expect to be characteristics
of a transmission from aliens. This will make it difficult to pick out
such signals.
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- But prospects for mitigating noise in space and in the
oceans are slim at best. Demand for bandwidth seems insatiable as communication
becomes even more important for more people.
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- In the seas, regulating Naval shipping traffic or oil
prospecting seems a Herculean task that would require cooperation from
diverse states, some of which are unfriendly to the West. Although some
of the corporations that ply these trades have shown interest in turning
down the volume, their shareholder interest is paramount and serious mitigation
could be very expensive.
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- Furthermore, the basic understanding of how noise affects
sea creatures is flimsy at best, and everyone agrees that more research
needs to occur before sound policies can be implemented. The National Marine
Fisheries Service is putting together a proposal for expanded noise regulation
in US waters, which would be a start but would still fail to address the
global aspects of the problem.
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- But the greatest fear is that these policies and protections,
if they arrive at all, will be too late both above and below. "I suspect
there will be some point where no matter how inventive we are it may become
impossible to sort out the signals we are looking for," says Shostak.
"At that point, all you can do is move the whole project to the back
side of the moon."
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