[Coral-List] Goreau paper; resilience

Douglas Fenner dfenner at blueskynet.as
Sun Mar 12 17:19:50 EST 2006

The Goreau paper is indeed a classic and a great introduction to coral reefs; I used it in teaching many times and highly recommend it, its great to have it available again, many thanks!!!  (interesting about the publication delay, didn't know that!)

I wanted to just comment on the two paragraphs in the message about resilience.  First, I don't think anyone suggests that coral reefs will always bounce back from any disturbance, no matter what we do.  That's rediculous.  If people produce a chronic disturbance that badly damages a reef, then is the reef going to bounce back after an acute disturbance?  No way.  But, if a reef is totally undisturbed by humans, will it bounce back from a natural disturbance?  Almost surely.  I live in American Samoa, on an island that is 1.5 million years old.  Hurricanes hit the island an average of about once per 5 years.  So it has had about 300,000 hurricanes during the island's lifetime, and the reefs are still here (about 28% coral cover at the moment).  Guam usually has several hurricanes each year, and is old too.  In one of my first trips to the Philippines, I saw a reef that had been hit by a hurricane a month earlier.  One area had had coral growing on rocks small enough for the hurricane to move.  The rolling rocks had crushed over 99.9% of the coral, everything was dead rubble.  I came back a few years later, and couldn't find the spot, even though it was right in front of the dive shop.  Then I realized it was an area now covered by about 80% live coral- a riot of gorgeous healthy coral of a wide varitey of species!!!  Incredible, saw it with my own eyes.  And the Philippines is not known for the world's most pristine reefs.  In Cozumel, after Hurricane Gilbert, the second most powerful hurricane on record before it made landfall, I saw a temporary algae bloom that went away, and corals recovering, even though the reefs there had about 2000 dives a day, and this was after the Diadema dieoff.  But then the reefs are in a park, in strong clear oceanic currents, and are swarming with fish including herbivores, and have very limited macroalgae, and bleaches little or not at all during mass bleachings in the Caribbean.  It was one of the few resilient reefs left in the Caribbean.

The claim that "Those touting "resilience" claim that we should do nothing at all and the reefs will recover all by themselves", " is itself pretty amazing, who said that, where is that quote from??  I can't believe anybody said that.  Resilience people are saying that if chronic human impacts are kept to low enough levels, this will help reefs recover on their own from disturbances.  Working to reduce chronic human impacts is certainly doing something, anybody who has tried it knows its darn hard work and most of the time we're not very successful.  He is right we are saying that if a reef is healthy enough we don't need to do restoration after a disturbance.  Nobody was helping American Samoa reefs after those 300,000 hurricanes, and the reefs recovered.  But if we do nothing as Goreau is claiming resiliance people are saying, and just let the chronic impacts, such as overfishing, sedimentation, and nutrient imputs, go on and get worse, the reefs will very likely undergo a phase shift after a disturbance, just as I recounted for SW Madagascar, and which happened in Jamaica years ago.  In fairness, when Tom's talking about "doing nothing", what he means is "doing nothing to actively restore the reef."  He just didn't say it that way, and it sounds like resilience people are saying "don't do anything, just watch the reefs die."  Which they aren't saying at all.
     Tom Goreau has a company with a patent for biorock, a form of active reef restoration using electric current.  So what he's advocating is active restoration of reefs using his method.  That's another option.  We can use all the options we can get, its going to take everything we can do to make a dent in the ongoing loss of coral reefs.  Personally, I tend to think we need to stop the things that are causing the problem in the first place, that would be the best solution.  But as we all know that's a lot easier said than done, and we haven't managed so far very well, as the huge decline in coral cover in the Caribbean shows.  Active reef restoration is definately needed in some places.

Coral and Coral Reefs
Thomas F. Goreau, Nora I. Goreau, Thomas J. Goreau

This paper, still the classic introduction to the field, was written 
around 1970, but its publication was delayed by nearly 10 years 
because the publishers did not think coral reefs were of sufficient 
interest to the public.

It was written at a time when large scale coral bleaching, coral 
diseases, and coral reef eutrophication were unknown, or confined to 
tiny areas with extreme local stresses. All of that changed in the 
decades after this paper was published, as coral reefs began dying on 
a large scale and the reefs described in this paper virtually 

Nevertheless this paper makes clear that even then the most 
experienced coral reef researchers were aware that coral reefs were 
exceptionally vulnerable systems and could be easily destroyed by 
human activities. We knew that they were highly sensitive, but did 
not yet realize just precisely how fragile they were.

It was only in the following decade that we were able to 
quantitatively establish the precise tolerance limits of coral reefs 
to global warming and nutrient pollution and found they were the 
lowest of any ecosystem. The temperature limits have now been 
established as 1 degree C above normal for the duration of the 
warmest month to cause large scale bleaching, and a bit above that to 
cause serious mortality (see other papers on this web site).

The nutrient limits above which massive overfertilization of the 
algae causes them to overgrow and kill the reef has been found to be 
1.0 micromole per liter (0.014 ppm) of available nitrogen and 0.1 
micromole per liter (0.003 ppm) of available phosophorus (see other 
papers on this web site). Along with the massive global outbreaks of 
new coral diseases that started after this paper was written (see 
papers posted on this web site), these new limits and the older 
scientific studies documented in this paper clearly refute the 
popular fad of "resilient reefs", which is now being touted by 
governments, international funding agencies, and large environmental 

This hypothesis claims that coral reefs will bounce back from any 
human caused stress all by themselves, no matter what we do, which 
cannot be supported by any long term observations. It serves as a 
smoke-screen designed to prevent action to reduce global, regional, 
and local stresses to reefs, and block efforts to restore damaged 

Those touting "resilience" claim that we "should do nothing at all 
and the reefs will recover all by themselves", are getting huge sums 
of funding from the US and Australian Governments and the World Bank. 
Their actions are directly responsible for speeding the rate of reef 
destruction and preventing action when it could have made a 

A few corrections to the paper are needed. The subtitle should say 
that reefs are the most species rich ecosystem in the oceans, not on 
earth. This unfortunate error was made by the editors, we were always 
fully aware of the unique diversity of rain forest insects. The 
drawings and maps were done by the magazine staff and are very poor 
compared to the original drawings we submitted, which we will also 
post in due course.

With these caveats and updates, this paper serves as an ideal 
introduction to corals and coral reefs when supplemented by the later 
papers on coral reef bleaching, diseases, eutrophication, and 
restoration posted on this web site.

Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139

(Click below to download the paper in PDF form. (4.2MB)

Dr. James M. Cervino, MS, Ph.D.
Marine Pathology
Department of Biological & Health Sciences
Pace University New York NYC
Phone: (917) 620-5287
Web site: http://www.globalcoral.org

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