[Coral-List] what agency should list corals
douglasfennertassi at gmail.com
Sat Apr 13 06:02:42 EDT 2013
I should add that coral reefs do have at least one kind of cycle.
That is the cycle of disturbance and recovery. Joe Connell and colleagues
have photographed individual staked quadrats at Heron Island on the Great
Barrier Reef, and followed them for decades. Individual quadrats have
coral cover that goes up and down, apparently going down with disturbances
and rising in between disturbances. We know coral reefs are subjected to
natural disturbances, hurricanes being an example of a major disturbance,
and there are other types of disturbances as well. The cycle of
disturbance and recovery is likely to be something reefs go through
continually. Such "cycles" of disturbance and recovery are not "cycles" in
the sense of sinusoidal waves, but rather may be closer to a sawtooth shape
over time, with a sudden drop in coral cover with a brief disturbance, the
amount of the drop varying with intensity of the disturbance, and the time
between disturbances also varying greatly, so that recovery may be in any
stage from just beginning to finished when the next disturbance arrives.
At any one location, hurricanes arrive most often in hurricane season, but
otherwise in near-random times. The frequency of hurricanes varies greatly
by geographic location.
This is relevant because of a new article that details the
disturbance of a set of reefs that are subject to low human impact, and
their subsequent recovery. The reefs are Scott Reefs off of the northwest
coast of Australia. The article appeared in Science, along with a popular
article on the subject. It is good to see that at least some reefs can
still recover from disturbances, even fairly quickly. This appears to be a
demonstration of a reef system with low human impacts that is very
resilient. We know many or most reefs are not this resilient, and we need
to reduce human impacts to get them more resilient. Cheers, Doug
Gilmour, J.P., Smith, L.D., Heyward, A.J., Baird, A.H., and Pratchett,
M.S. 2013. Recovery of an isolated coral reef system following severe
disturbance. Science 340: 69-71.
The popular article is:
Polidoro, B. and K. Carpenter. 2013. Dynamics of coral reef recovery.
Science 340: 34-35.
Also of interest on the topic of resilience is the popular article:
Schmidt, C. 2013. As threats to corals grow, hints of resilience emerge.
Science 339: 1517-1519.
On Fri, Apr 12, 2013 at 3:30 PM, Douglas Fenner <
douglasfennertassi at gmail.com> wrote:
> So are you saying that corals might be like bamboo, and all the
> corals on a reef might just naturally all die every once in a while, and
> that's why corals have died in the Caribbean and other places?? Since
> corals have died off in the geological record, maybe that's what's
> happening. Corals are programmed to die every once in a while? All the
> different species of corals on the reefs are biologically programmed to die
> at the same time? Different species of bamboo reproduce and die on
> different cycles of 2 to 120 years, you told us. Hmmm, in some places all
> the corals reproduce at once on one night, like the Great Barrier Reef.
> Maybe they all die after that? But they reproduce on one night every year,
> and I know of no report they die right after that. Did the Caribbean
> corals all reproduce just before they all started to die? Hmmm, there are
> some corals that get very large and very old, hundreds of years. The North
> Queensland Museum has a core from one where about 700 years were counted.
> Didn't seem to spawn and die, probably spawned every year, and the coral is
> still alive as far as I know. Frankly, I've never heard of anything that
> would fit your hypothesis with corals, and I've heard a lot of evidence
> that indicates they don't do that, plus a bit of logic- do we really think
> that on a reef in Indonesia where there are 400 or more species of coral,
> every once in a while they all just spontaneously reproduce and die?
> Indeed natural cycles are interesting, but that doesn't mean corals
> are like bamboo. Maybe they are more like strawberries, reproducing both
> sexually with flowers and asexually by runners. There is even a thing
> called the "coral-strawberry model" discussed by Williams (1975). If you
> are interested in cycles in ecosystems, books on ecology often have quite a
> bit of information on that, some aspects of some ecosystems do cycle, like
> lemmings and predators that eat them. But more relevant, mass die-offs of
> corals usually have a cause. Rather obvious in the Indian Ocean in 1998,
> when water temperatures skyrocketed and in many reef areas most of the
> corals turned white and died. Obvious on some Caribbean reefs when
> Acropora got white band disease and died. Indeed the causes are much more
> obvious for some die offs than for others. A long list of causes for the
> decline of coral reefs is well known, "Reefs at Risk" lists causes they
> think are the most important, and the report (open access) on the corals
> proposed for endangered status reviews a long list of them in considerable
> detail. I don't remember spontaneous mass mortality, whether after
> spawning or not, as one of the things listed.
> Cheers, Doug
> Williams GC (1975) Sex and evolution. Princeton University Press,
> Princeton, NJ
> Reefs at Risk Revisited www.wri.org/publication/reefs-at-risk-revisited
> Status Report on 82 Corals: go to
> http://www.nmfs.noaa.gov/stories/2012/11/82corals.html find status
> report on right, click on it to download
> Cheers, Doug
> On Thu, Apr 11, 2013 at 7:35 AM, Eugene Shinn <eugeneshinn at mail.usf.edu>wrote:
>> Looks like the subject of "what agency should list corals" will not go
>> away. Probably the best answer is: no agency should list corals. Listing
>> them surely will not change Co2 levels in the oceans in time to make a
>> As for worries about population there is some good news in Science 2.0,
>> 5 April 2013
>> It says global population is dropping and will continue until around
>> 2090. As for the waste water situation in the Florida Keys which was my
>> research baby for more than 10 years, I remind people that everything
>> that happened to Keys reefs (centered mainly around 1983) also happened
>> to reefs synchronously around small isolated islands in the Bahamas and
>> Caribbean at the same time (and don't forget that was when Diadema died
>> throughout the Caribbean). It is a real stretch to blame sewage in those
>> cases. Remember there are species of bamboos that die off synchronously
>> worldwide about every 40 years ( some longer) and the cause is not
>> climatic. Here is a quote from an article in Annals of Botany. 82:
>> 779-785, 1998. "Bamboos are woody perennials some species of which show
>> the peculiar habit of dying after flowering just once, in long life
>> cycles of 2 to 120 years (McClure, 1966). Should they be listed?
>> Fortunately there there are historic records of their death (and
>> resulting Panda demise) that stretch back hundreds of years. We don't
>> have long historic observations for corals but do have geologic evidence
>> of their demise in the past. Are not natural cycles interesting? Gene
>> McClure FA. 1966. The bamboos, a fresh perspective. Cambridge,
>> Massachusetts: Harvard University Press. No
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> The views expressed are those of the author alone.
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