[Coral-List] threats to coral from seismic testing

[Steve Gittings]

If you're talking about airguns used for 3-d seismic, such an exclusion 
zones would seem excessive.  I'm not aware of such zones.  I have been 
in the water less that 1.5 km from a large multi-airgun 3-d survey and 
while you could hear and feel, to some extent, the percussion, it 
certainly didn't seem dangerous.  The power curve for airgun explosions 
that I've seen, and the fact that they are low velocity explosions, 
suggest fairly localized danger zones (a few meters) around the 
discharges.  Beyond those distances, there would seem to be little 
danger of direct damage to reefs or most organisms associated with 
reefs.  As I recall, the Minerals Management Service funded some work on 
the U.S. west coast on impacts.  Investigators were able to document 
fish retreating for cover as the airguns passed over, but if memory 
serves, no other impacts.

Airgun surveys have been conducted directly over the reefs of the Flower 
Garden Banks National Marine Sanctuary in the northwestern Gulf of 
Mexico with no discernible effects.  There is, however, uncertainty 
about the impacts of airgun surveys on the behaviors of animals that 
depend on sound to communicate, such as cetaceans.  Some feel that they 
may alter feeding or other aspects of life for these animals, but I 
haven't seen any hard data on this.

tim ecott wrote:
> hi coral-listers,
> i am trying to find sources/references for any data or studies on the 
> possible impacts of seismic testing on coral reef communities. in 
> particular i am keen to know if anyone has expertise on the possible 
> negative effects of seismic testing done for oil/gas prospecting? I 
> understand that during seismic tests of this nature there is an 
> exclusion zone for divers of up to 28 kilometres - which would imply 
> fairly large sonic disruption!
> sincerely,
> time ecott
>
>
>
> tim ecott is the author of
> Neutral Buoyancy: Adventures in a Liquid World (Penguin) and
> Vanilla: Travels in Search of the Luscious Substance (Penguin)
>
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