🚀 go-pugleaf

baez@guitar.ucr.edu (john baez) writes:

>Ahem, ignore that previous post please.  Today I read in the paper that
>some jerks at the Scripps Institution of Oceanography in San Diego want
>to put a loudspeaker in the Pacific off Big Sur and Kauai that will
>broadcast a 195-decibel sound underwater every four hours for *twenty
>minutes* from now until 2004!!!  This is in the March 22nd LA Times.

This topic has been hotly discussed on the marine mammal mailing list
(MARMAM) for the past several weeks.  A hearing on the ATOC project has
been scheduled at NMFS in Maryland for April 22.  I'll post the initial
message from Feb 2 which brought the issue to the attention of the list.
The two authors are respected marine mammal scientists (specializing in
sperm whales I believe), and I am presenting verbatim their report without
permission and with the intention of spreading information.

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I am quite concerned that the following issue has not received the
necessary publicity to lend itself to healthy dialog about this matter.
I am referring to two extremely loud sound sources that are starting
operation this month and next month, off 1) Kauai, Hawaii and 2) Pt. Sur,
California, which is an especially productive area rich in marine mammal
life.  The speakers are to be placed at a depth of about 700-800 m just off
the coast of these two locations.  The intensity of these sound sources will
be about 195 dB.  This is about 10,000,000 times 120 dB (dB is a logarithmic
scale).  120 dB is the level of intensity at which even the comparatively
acoustically insensitive grey whale avoids noise.  120 dB is also the threshold
of pain for humans for airborne sound.  The sound sources will be broadcasting
a fairly low-pitched sound, 70 Hz in frequency (human hearing extends down to
20 Hz).  The sounds will remain on for a duration of 20 min, off for 4 hrs,
on for 20 min., etc. for the next few years at least and probably decades.
Sound sources like these are also proposed for the Atlantic and Indian oceans
as well, effectively assaulting the oceans of the world for the next decade
with noise.  The sounds are loud enough to travel halfway around the world
using the deep sound channel.
    The "ATOC" (Acoustic Thermography of Global Ocean Climate) Project's
purpose is supposedly to examine global temperature trends in the ocean,
as a way to monitor global warming, since the speed of sound increases with incr
easing water temperature.  The multi-million dollar project is funded by
the U.S. Dept. of Defense (ARPA).  Many climatologists question whether ATOC
is the best way to gauge global warming, especially as the source is located
so far (800 m) below the ocean surface.
     As you know, whales, especially toothed whales, are critically dependent
on sound, often both for social communication as well as for food-finding.
Deep-diving whales are likely to be the species most affected by the sound.
Sperm whales regularly dive to 400 m depths and beyond, bringing them into
potentially close contact with the ATOC source.  They are also extremely
acoustically sensitive, as anyone who has spent any time at all with them,
knows.  Beaked whales could also be affected.  Humpback whales off Newfound-
land have been found with shattered ear bones, likely as a result of sound
levels that were thought to be much less intense than those used by ATOC.
     Studies of the effects of ATOC's sound sources on marine mammals are
being undertaken by ATOC.  Unfortunately, these studies commence at roughly
the same time as the ATOC source begins operation, enabling little or no
baseline information to be gathered.  It will be very hard to document any
clear disturbance since effects on marine mammals could be occurring beyond
the horizon from the source or at great depth.  In addition, it will be
almost impossible to ascertain whether whales will be suffering habitual
hearing impairment.  If whales are gradually being deafened by the sound
source, they will show less and less disturbance from the sound over time,
leading to erroneous conclusions of "no adverse effects".  Alternatively,
one blast of 195 dB may be enough to permanently damage the hearing (or
cause other physiological damage), invalidating any results that occur
subsequently.  WE JUST DO NOT KNOW, NOR ARE WE LIKELY TO FIND THIS OUT GIVEN THE
 DIFFICULTY OF STUDYING SPERM WHALES, ESPECIALLY AT DEPTH OR BEYOND THE
HORIZON.  Tags will hopefully help in answering this question, but as the
source cannot be moved, will provide few test cases.  (0ne has to wait until
a tagged whale passes by at relatively close distance to the speaker).  The
potential psychological stress of a sound that is regularly on for 20 min at
a time around the clock for years and years will be even more impossible to
evaluate.
     The feasibility test for ATOC was conducted off Heard Island on an even
greater intensity level (around 215 dB) in 1991.  This was done without filing
permits for marine mammals, and the sound was heard 18,000 km away in Bermuda
WITHOUT SIGNAL PROCESSING OR FILTERING NEEDED.  One wonders why such a loud
sound was needed.
     In conclusion, the most alarming aspect of this project is the dearth
of publicity it has received, considering its far-ranging potential implications
 for marine mammals and marine life in general.  The permits for the two sound
sources were filed and the Hawaii one has gone though a 30 day public comment
period on the Federal Register with hardly any comments noted!  The California
30-day period on the Federal Register is happening now, I think.  Please
give comments to NMFS or the Marine Mammal Commission SOON!

     Lindy Weilgart and Hal Whitehead

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The opinions expressed do not represent those of my employer.
-- 

Eric Geisler			/////\\\\\/////\\\\\/////
egeisler@qualcomm.com