[Coral-List] Corals Persist But Bioerosion Rises in Low-pH Waters (Anne Cohen)

Douglas Fenner douglasfennertassi at gmail.com
Tue Jun 9 17:54:28 EDT 2015

     Good point, experimental evidence would be good.  I looked at the
article, looking to see if they refer to any experimental evidence that
lowered pH increases bioerosion.  In their discussion, on page 4, they
state that:
   "Our hypothesis that low pH causes the observed increase in coral
macrobioerosion is supported by multiple laboratory experiments that show
elevated bioerosion at low pH (30–32). Furthermore, in a recent field
study, pH/Ωar emerged as a consistent factor in *Porites* macrobioerosion
on 11 Pacific reef systems (15) spanning a wide range of pH, wave energy,
and flow conditions (33)."  I've copied those references at the end of this

    Most (but not all) bioeroders are filter feeders, so their populations
respond to how much plankton there is in the water to feed on.  Mike Risk
has made this point more than once.  Clams and sponges are a couple
examples of filter feeders, and boring species are dependent on plankton
feeding as are non-boring species.  I would think Biscayne Bay gets more
nutrient inputs (being near major human populations and partly enclosed),
and therefore likely has more plankton for them to feed on, than more open
water areas like the Florida Keys and the Bahamas.  But that's a
hypothesis, there is probably literature to test it with.  Likely, the
lagoons in Palau which are small bays between the limestone Rock Islands
which are heavily forested and have no human population (from the photos
I've seen) have quite low nutrient inputs and plankton levels.  Again, a
hypothesis, I bet someone knows.

     If larval retention in bays was the reason for more bioeroders and
biofouling organisms than in open areas, why wouldn't it produce higher
abundances of all marine species that have planktonic larvae, not just
bioeroders and foulers?  If larval retention causes increased populations,
there should be more of everything (except the few without planktonic
larvae, like sharks).  Again, a hypothesis, maybe someone can tell us
whether Biscayne Bay has higher populations of all animals including
corals, than the open places like the Keys and the Bahamas have.

    Cheers,  Doug

15. T. M. DeCarlo, A. L. Cohen, H. C. Barkley, Q. Cobban, C. Young, K. E.
Shamberger, R. E. Brainard, Y. Golbuu, Coral macrobioerosion is accelerated
by ocean acidification and nutrients. Geology 43, 7–10 (2015)

30. M. Wisshak, C. H. L. Schonberg, A. Form, A. Freiwald, Ocean
acidification accelerates reef bioerosion. PLOS One 7, e45124 (2012).

31. A. Tribollet, C. Godinot, M. Atkinson, C. Langdon, Effects of elevated
pCO2 on dissolution of coral carbonates by microbial euendoliths. Glob.
Biogeochem. Cycles. 23 (2009).

32. C. Reyes-Nivia, G. Diaz-Pulido, D. Kline, O.-H. Guldberg, S. Dove,
Ocean acidification and warming scenarios increase microbioerosion of coral
skeletons. Glob. Chang. Biol. Biol. 19, 1919–1929 (2013).

33. J. M. Gove, G. J. Williams, M. A. mcManus, S. F. Heron, S. A. Sandin,
O. J. Vetter, D. G. Foley, Quantifying climatological ranges and anomalies
for Pacific coral reef ecosystems. PLOS One 8, e61974 (2013).

On Tue, Jun 9, 2015 at 3:32 AM, Eugene Shinn <eugeneshinn at mail.usf.edu>

> The Woods Hole press release is interesting. I was concerned about the
> proposed connection between acidification and increasing numbers of
> borers. One would like to see some experimental evidence that borers
> actually favor lower pH. Do such experimental data exist? Borers that
> attack wood piling, boats, and limestone do favor areas of restricted
> circulation over areas of increased oceanic circulation. For example,
> Biscayne Bay supports far more boring and fowling organisms than do the
> more open waters of the Florida Keys and the Bahamas. Those differences
> in boring fauna are not related to pH. Most likely the greater abundance
> of rocky intertidal surfaces in Biscayne Bay that boring and other
> fowling organisms favor combined with longer retention time of larvae in
> an environment favorable to their success account for the bay’s
> increased numbers of boring organisms. Those conditions also are found
> in the many lagoons of Palau. Could it be that the greater numbers of
> boring organisms that attack coral skeletons there has nothing to do
> with acidification? Experimental data may be needed to determine if pH
> is the culprit. Gene
> On 6/8/15 12:00 PM, coral-list-request at coral.aoml.noaa.gov wrote:
> > Corals Persist But Bioerosion Rises in Low-pH Waters (Anne Cohen)
> --
> 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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Douglas Fenner
Contractor with Ocean Associates, Inc.
PO Box 7390
Pago Pago, American Samoa 96799  USA

phone 1 684 622-7084

"belief in climate change is optional, participation is not."

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