[Coral-List] Effects of nuclear testing on coral reefs

Nicole Crane nicrane at cabrillo.edu
Fri Jul 21 12:14:22 EDT 2017

Super interesting.  I will point out a couple of things:

James Stewart (a colleague of mine) was the Diving Safety Officer, not the Dive Master, for Scripps. I know that seems picky, but it would have been important for him.

In determining ‘safe’ levels of any potentially toxic or damaging agent, its important to consider what that means.  Seeing fish and sharks swimming happily around, and seeing corals grow does not necessarily mean the ecosystem has not suffered some long term ‘damage’ however we may define that.  We have been very wrong in the past with our assessment of safe levels of things, only to see them accumulate in the environment (apparently not a problem based on ‘safe’ levels) and come back to cause real problems. Imagine an outside entity evaluating human populations…let’s say this entity sees a community of people, plenty of kids etc.  The fact that they are all surviving and reproducing might be the determining factor for ‘healthy’ or ‘recovred', but what if they are all severely compromised in another way that the observer doesn’t see because they don’t understand to look for it?  Of course that wouldn’t happen with humans (at least not if its obvious), but we don’t really know enough about happily swimming sharks and fish to really make that assessment.  So I would caution how we determine ‘healthy’, and at least recognize our own deficiencies in our determinations.  Its not because we understood toxicity, or accumulation, for example, that some seemingly benign flame retardants for safety have ended up in very high concentrations in killer whales off California, suggesting problematic bioaccumulation in our ecosystems…

Not saying these studies discussed below are wrong or not worthy of optimism at all.  Just saying we should always have perspective


> On 20 Jul 2017, at 9:58 AM, Eugene Shinn <eugeneshinn at mail.usf.edu> wrote:
> I read the papers cited in Maria Beger’s posting and the one mentioned 
> by Peter Sale with great interest. The conclusion confirms our 
> observations at Enewetak in 1984.
> First some background and why we were there. Our mission was to 
> determine the size of nuclear craters created at the time of the event 
> rather than the size one observes today. It was known that the submarine 
> craters began enlarging and deepening immediately after creation. Such 
> enlargement is less likely to occur with craters made by bombs on dry 
> land.Why was this important? In the early 1980s congress was arguing 
> over a proposed nuclear defense system called the MX Missile Program. 
> Should we have ballistic missiles on moving trains to hide their 
> locations from the enemy or put missiles in hardened silos? If in silos 
> what should the spacing between silos be?No one knew the exact diameter 
> of a crater made by a 10-megaton bomb. We could not do surface testing 
> to find out. However, the US had tested these size bombs (devices) on 
> atolls in the Marshall Islands. Unfortunately the present craters had 
> increased in size due to compaction and dewatering than that produced at 
> the instant of detonation. As geologists with the USGS our mission was 
> to do geological detective work and determine crater size at the instant 
> of what the Defense Nuclear agency called “the event.” That would in 
> theory provided the knowledge of spacing needed for MX missile silos. We 
> were very successful and were also told we could pursue any other 
> geological or biological process of interest we thought important---and 
> we did as described below.
> All of us were impressed at the variety and abundance of corals and fish 
> as well as the lack of residual radioactivity. A general cleanup of 
> radioactive material had already been conducted and placed under a 
> cement dome covering a crater on one of the islands. Everything we 
> collected was checked for radioactivity and revealed safe levels. A 
> major surprise was that growth rings in live half meter high /Porities/ 
> head corals growing near the lip of Koa crater revealed they recruited 
> and began growing in 1958, the same year the crater was created.A large 
> 2-meter-high /Porities/ head about 1 km from Oak crater created by a 
> 9-megaton device was also cored. The Geiger counter revealed low-level 
> activity in the coral band that formed the year of the shot. Its growth 
> rate had not been affected and growth rates afterwards matched growth 
> rate before the atomic test.Fish and especially sharks were abundant and 
> aggressive. We concluded that the reef (except within the huge craters) 
> was minimally affected. Significantly the human population had been 
> excluded from the atoll (as it was at Bikini) and there had been no 
> fishing conducted there since the testing. This concurs with the 
> observations at Bikini as reported on the coral-list.
> Before going to Enewetak I had a brief conversation with James Stewart 
> the long time dive master at Scripts who recently passed away at age 89. 
> He told me he had dived in the hydrogen bomb crater known as Koa crater 
> just 3-days after the blast. I felt relieved when I found myself diving 
> in that same crater 26 years later.Gene
> -- 
> No Rocks, No Water, No Ecosystem (EAS)
> ------------------------------------ -----------------------------------
> 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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