[Coral-List] Coral mortality in a warmer and acidified ocean

Risk, Michael riskmj at mcmaster.ca
Fri Jan 27 10:45:27 EST 2017

Fascinating, Gene.

I await feedback from the rest of the 8,000-odd on the -list, those who are still able to respond after the recent political changes in your county.

The implication, or the inevitable conclusion, is that the recent decline in Acropora has been caused by local stresses, not global change. This is something many in the reef community find hard to accept.

From: coral-list-bounces at coral.aoml.noaa.gov [coral-list-bounces at coral.aoml..noaa.gov] on behalf of Eugene Shinn [eugeneshinn at mail.usf.edu]
Sent: January 25, 2017 12:43 PM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Coral mortality in a warmer and acidified ocean

*In addition to the paper reviewed in the previous Coral-list here is A
review published in the blog Co2 Science   Gene

*Paper Reviewed*
Stolarski, J., Bosellini, F.R., Wallace, C.C., Gothmann, A.M., Mazur,
M., Domart-Coulon, I., Gutner-Hoch, E., Neuser, R.D., Levy, O., Shemesh,
A. and Meibom, A. 2016. A unique coral biomineralization pattern has
resisted 40 million years of major ocean chemistry change. /Scientific
Reports/ *6*: 27579, DOI: 10.1038/srep27579.

Publishing their work in the journal /Scientific Reports/, the team of
eleven international researchers compared the skeletal structures of
living /Acropora/ corals with those of well-preserved fossil /Acropora/
skeletons from the Eocene, Oligocene, and Miocene, noting that these
latter organisms "have experienced major fluctuations in atmospheric CO2
levels (from greenhouse conditions of high pCO2 in the Eocene to low
pCO2 ice-house conditions in the Oligocene-Miocene) and a dramatically
changing ocean Mg/Ca ratio." By doing so, it could therefore be
empirically determined whether or not higher levels of CO2 (i.e., ocean
acidification) truly are a detriment to corals, interfering with the
process of calcification and disrupting or weakening skeletal structure.

So is that what they found? Were these major reef building corals harmed
by ocean acidification and temperature changes of conditions past?

In a word, /no/. In stark contrast, in fact, Stolarski /et al/. report
that "the most diverse, widespread, and abundant reef-building coral
genus /Acropora/ (20 morphological groups and 150 living species) has
not only survived these environmental changes, but has maintained its
distinct skeletal biomineralization pattern for at least 40 My." Such
"remarkable evolutionary stability," they continue, "exists despite
major global geochemical fluctuations, from greenhouse (high pCO2)
conditions and low seawater Mg/Ca (calcitic seas) in the Eocene to
icehouse (low pCO2) conditions and rapidly increasing Mg/Ca (aragonite
seas) during the Oligocene-Miocene."

The take home message of the Stolarski /et al/. paper is that the
skeletal formation process of /Acropora/ is, as they state, "strongly
biologically controlled," uninhibited by changes in temperature or
seawater chemistry, including seawater pH/ocean acidification conditions
that are predicted to occur over the course of the next century and beyond.


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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