[Coral-List] Rau, McLeod and Hoegh-Guldberg outline strategies to brace for impact in the face

John McManus jmcmanus at rsmas.miami.edu
Sat Sep 1 14:38:12 EDT 2012

This is an interesting article. However, I think we have to keep the concept
of active local intervention (shading, local chemistry adjustments, etc.) in

A typical coral reef is about 1 square kilometer, which is a million square
meters. Active intervention at that scale is unlikely to be feasible for
more than a handful of reefs. More feasibly, a larger number of small coral
patches in the 100 - 500 meter diameter range, the size of those usually
found in the middle and upper Florida Keys, could be subjected to serious
active intervention, resulting in perhaps a decrease in, or temporary
staving off of, extinction of some species -- a bit like zoos or arboretums.

The idea of accelerating the adaptation rates of nature seems currently to
hold more promise. Humans have radically (though deleteriously) modified
genetic compositions in salmon and prawns over enormous coastal expanses via
improper aquaculture practices, by the reduction in genetic diversity which
increases susceptibility to disease outbreaks. One can imagine turning this
scenario around to where more rationally directed efforts can be made to
disperse resistant coral and or Symbiodinium genotypes, while still keeping
diversity as high as practical. 

Even with that, we still anticipate losing many calcareous species over the
next century, and shifting ecosystems via reductions in swimming speeds and
viabilities in some other species. I would certainly expect coral cover as a
whole to continue declining with increased rapidity. Some reef structures
now at the sea surface may be a meter or more below that, with altered
ecosystems. The villages that often survive only because of that wave
protection will be gone or moved up slope, and entire low-island territories
and nations will be vacated as freshwater lenses fill with seawater and land
begins to disappear. 

However, tragic though this may be,  we have to realize that there will
still be important ecosystems present where coral once dominated. Already,
the average coral cover in the Caribbean is believed to be below 15%, and
many economically important 'coral reef' ecosystems have less than 5% hard
coral cover. The fish production of such places is much less than that where
coral  is more abundant. However, low-income fishers still make their
livings there, and the tourists who continue to flock there often don't know
what they are missing. Marine hard substrates, other than those subjected to
extreme pollution or periodic sand scouring, are generally highly diverse
ecosystems -- especially in the tropics.  

The more rare that high diversity ecosystems become and the higher that
human population levels rise, the more valuable the remaining high diversity
ecosystems grow. Thus, regardless of what is happening to the world's
oceans, it is going to be increasingly important in the future to keep
public environmental awareness as high as possible, to reduce overfishing
and pollution, and to specifically protect coral reef ecosystems or whatever
replaces them in given locations. 

So, until the genetic strategies have been worked out, the major role that
divers can take is to step up their efforts to protect these ecosystems with
every bit of energy they can muster.


John W. McManus, PhD
Director, National Center for Coral Reef Research (NCORE)
Professor, Marine Biology and Fisheries
Coral Reef Ecology and Management Lab (CREM Lab)
Rosenstiel School of Marine and Atmospheric Science (RSMAS)
University of Miami, 4600 Rickenbacker Causeway, Miami, 33149
jmcmanus at rsmas.miami.edu      http://ncore.rsmas.miami.edu/
Phone: 305-421-4814   

"Far better an approximate answer to the right question, which is often
   than an exact answer to the wrong question, which can always be made
     --John Tukey, Statistician, National Medal of Science and IEEE Medal of


-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Reese, Jessica
Sent: Thursday, August 30, 2012 12:42 PM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Rau, McLeod and Hoegh-Guldberg outline strategies to
brace for impact in the face

Coral Listers,


Mother Jones ran an article, today, about a recently published open-access
paper by Rau, McLeod, and Hoegh-Guldberg (2012) entitled The need for new
ocean conservation strategies in a high-carbon dioxide world. The popular
press article can be accessed here:


The Mother Jones article, unwisely, presents the ideas as "crazy", and even
goes so far as to picture tube sponges being sheltered from thermal stress
by beach umbrellas.  The open access article, however does not strike me as
crazy at all. It's a call to action for the scientific community to look to
new management and conservation strategies, for the evaluation of their
success, followed by policies to support those silver bullets when and if
they become identified. The open-access paper can be accessed here:


As zoo educator who is well-versed in the science of climate change and
coral reefs, and a passionate PADI Dive Master, I worry constantly about how
these ecosystems will survive. Since December 2009, it has become abundantly
clear to me that we are pitifully off-course to stabilize or adequately
mitigate our global CO2 concentrations. Yet, divers, all over the world
continue to enjoy these resources, often without any education about what
stressors they are facing. Do you, the coral scientific community see a role
for the recreational diver to engage in citizen science action to help these
ecosystems brace for impact and support their resilience? The strategies
that are recommended in the paper suggest possibilities such as using shade
cloths to reduce thermal stress, electrical currents to reduce bleaching and
encourage growth, selective breeding for heat tolerance, and managing
chemistry by adding carbonates, silicates, and dissolved bicarbonates sound
like exciting possibilities and inspire me to join in to help in any way
that I can.
While many of these experiments will be done in a lab, there may be cause to
try some in the field, which sounds very labor intensive.
Please let me know if you need any assistance in following Rau, McLeod, and
Hoegh-Gulberg's recommendations. I would love to get recreational divers
involved in the process of building resilience.


Best Fishes, <))))><


Jess Reese

Interpretive Programs Coordinator

Chicago Zoological Society/Brookfield Zoo

3300 Golf Rd. 

Brookfield, IL 60513

Direct Phone (708) 688-8861


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