[Coral-List] Distressing News for the Whole Pacific Ocean

Eugene Shinn eugeneshinn at mail.usf.edu
Wed Sep 4 11:47:01 EDT 2013

Listers, Don't loose too much sleep or become hysterical over the 
radioactivity in Pacific waters far beyond Japanese waters.  Here is 
some background that might ease your concerns. In the 1970s some very 
interesting coral research came out of the Mid Pacific Marine Lab at 
Enewetak in the Marshall Islands.  Although the tests at Bikini are more 
well publicized more that 40 atomic devices, including the first 
hydrogen bomb, were tested at Enewetak in the 1950s and early 1960s. 
After the tests researchers at the Mid Pacific lab on Enewetak studied 
many aspects of biology including growth banding in head corals. Corals 
were sawed and the sawed surface  was placed on X-ray film for several 
days in the dark. These corals in essence took their own picture and 
radioactive bands provided elegant proof that growth bands were annual. 
Although the growth bands laid down during detonations  clearly showed 
on the film the corals also showed no effect from radiation and 
continued to grow at pre-test rates. Later in 1983 I spent many hours 
diving in two of the largest fusion bomb craters. Several of us were 
coring a digging around in the craters to determine the size of the 
craters at the instant of the explosion (craters had enlarged during the 
intervening years). As part of our work Harold Hudson cored many 3-m 
high Porities heads in near  proximity of a 200 foot deep crater made by 
a 9 megaton blast. Geiger counter scans of the cores revealed the 
slightly radioactive zone made by the bomb. His study showed that 
Subsequent growth was not reduced. In addition, Hudson cored several 
meter-high heads that had begun growing within the edge of a smaller 
crater. Growth bands showed they settled and began growing less than a 
year after the device was exploded (published in proceedings of the 
Tahiti International Coral Reef Symposium). Sometime later I happened to 
talk with the dive master at Scripts Institute of Oceanography.  He told 
me he had dived in that crater 3-days after the blast! Another lesson we 
learned from the dosimeter we all carried was that we were exposed to 
more radiation flying at 30,000 ft to get to Enewetak than we 
encountered in and around the craters. This was a great surprise because 
we all knew that Plutonium has a 22,000 year half life. Certainly the 
waters had been highly contaminated by the events but had drifted off 
the atoll and was diluted in the surrounding depths. Most of the 
radioactivity had gone up into the atmosphere.  I know this is not the 
same as release of radioactive cooling water but shows that corals were 
not noticeably affected by the intense radiation they must have received 
when the devises were exploded. I might add that none of us involved in 
this research were affected that we know of. Maybe that's why I am 
forced to write these reports. However, remember there is a lot of water 
between Japan, the coral atolls, and the US west coast. Not to worry. Gene


No Rocks, No Water, No Ecosystem (EAS)
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E. A. Shinn, Courtesy Professor
University of South Florida
College of Marine Science Room 221A
140 Seventh Avenue South
St. Petersburg, FL 33701
<eugeneshinn at mail.usf.edu>
Tel 727 553-1158
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