[Coral-List] CO2 and the inconvenient truth

Michael Risk riskmj at univmail.cis.mcmaster.ca
Mon Nov 6 11:27:51 EST 2006

Hello Tom, colleagues.

I have just waded through many long Goreau-posts. One might say the
Devil makes work for idle hands, but I know your hands are far from
idle. The interesting thing is, I agree with almost everything you have

It intrigues me that coral reefs should be the only ecosystem on the
planet for which it needs repeatedly to be proven that nutrients are
important. There are several depressingly human reasons why this should
be so. First of all, because the system is so complex, developers (the
people with the money) can always hire a scientist who will say just
that: nutrients are unimportant on reefs. Second, managers and
government employees have an innate reluctance to admit that the
resource they were hired to protect has gone downhill under their
stewardship, from local causes. 

Much that appears on the -list has attributes more of an argument than
a discussion. In a discussion, the participants' minds may be
changed-in an argument, there is simply restatement of beliefs. And it
seesm there is little institutional memory on the -list.

Re Diadema: I repeat what I said some while back, on the -list: anyone
who believes the reefs of the Caribbean will come back when Diadema
comes back may as well believe in the Tooth Fairy. Many of the Diadema
postings come from those with professional or economic interests.

No doubt Diadema was an important grazer. No doubt, also, the reefs of
the Caribbean were in serious decline for years before the dieoff. In
fact, as Tom suggests, some of these matters are beyond debate, and
well past the time when action should be taken.

Martin Moe's posting posits a straw man: "Anyone who thinks Diadema was
unimportant, stand up!" to which I would say, it would be more
productive to seek ways to slow the decline by assessing relative
importance of threats. (Surely one of the dumbest things ever said in
science was said in Science a short while ago, to the effect that we
should not bother ranking threats to reefs...)

I was a member of a NOAA panel in....2000? that sat to evaluate the
efficiency of the various reef monitoring programs in the Florida Keys.
We were impressed by the quality and quantity of the programs, and
appalled by the extent of the decline. We concluded that a regional
mass extinction was under way-that was the phrase used, "regional mass
extinction." I'm a bit out of touch here-would someone please list for
me the rapid responses in Florida since then that have led to tertiary
treatment of sewage, controls on sedimentation...etc...

Some years ago, in the mid-80's, I suggested that "triage" be applied
to reefs. (I hate doing this sort of thing, but fact is, as Tom tells
us at regular intervals, a lot of excellent reef science was done
pre-pdf). So: give up on the Keys. They are beyond saving, and all the
"resiliency" programs in the world won't make a whit of difference.
Instead, examine places like Mauritius, recently the subject of some
posts. Mauritius escaped severe damage because it's at the lower limit.
In fact, it can be bloody cold!

There will be many places in the world, eg east coast of Florida, where
immediate control of nutrient input can save what resource is left, so
that at some time in the hopeful future we will have something to show
our grandchildren.

I close with an interesting example, one that may have escaped some.
(Again, I hate doing this, but the ref may not be readily available).
In Maldives, the diet is Skipjack Tuna. Almost nothing but. A Maldivian
cookbook consists of 300 recipes for curried tuna. Reef fish are
culturally considered trash, and not eaten. As in much of the Pacific,
grazing is dominated by fish-urchins are unimportant, relatively. 

In my career, I have bounced back and forth between geology and
biology. There are some observations I have collected over the years.

First of all, geologists have better parties. Sorry, guys. May have
something to do with the field tradition, or the hazardous nature of
some of the work or...who knows? 

Second, the two fields think differently, mathematically. Many
biologists are superb experimentalists. This drives their facility with
ANOVA. Geologists are often depressed by the realisation that their
experiments will take 10 million years, and they will not see the end
even if they avoid trans fats. So they observe, and use regression. 

On the capitol island of Maldives, Male, one can observe the end result
of an experiment in which the grazers have been left untouched, and
nutrients have been ramped up. Really ramped. Fifteen years ago, when I
last worked there, maybe 200,000 people lived on Male, which is
1kmx2km. All the sewage is discharged untreated through four big pipes
at the corners of the island. 

One could swim through huge shoals of tangs and parrotfish, over reefs
that were stone dead. (I describe this in the Maldives Chapter of the
McClanahan and Obura book on Reefs of te Indian Ocean.) 

Sadly, it is likely that this experiment has been terminated. The
Maldivians have learned that tourists love reef fish. What's more,
destructive fishing methods have been used there now for some time, it
is said by foreigners.

No one should be the slightest bit surprised that increased nutrient
input can kill reefs, even if the grazing community remains unchanged.

Again, the need for action is apparent, as is the directions it should


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