[Coral-List] corals will survive alkalinity shift

[Eugene Shinn]

Listers will enjoy this hopeful message from Environmental News Network. Gene
From: Scott Sincoff, ENN

Published April 2, 2012 09:28 PM

A new study has increased hope that some coral species will be able 
to survive gradual ocean acidification. According to new research 
published in the journal, Nature Climate Change, a team of 
international scientists have identified a specific internal 
mechanism that could permit some coral species and their symbiotic 
algae to offset the unfavorable effects of an acidic ocean. In 
addition, this research has given hope that coral reefs will also be 
able to survive rising levels of ocean acidification.


Besides being associated with allegedly raising the planet's natural 
temperature, carbon dioxide is turning the world's oceans more 
acidic. The research team from Australia's ARC Centre of Excellence 
for Coral Reef Studies (CoECRS), at the University of Western 
Australia (UWA) and France's Laboratoire des Sciences du Climat et de 
l'Environnement states in their report that carbon dioxide is being 
released at rates that were thought to extinguish some levels of life 
forms.



The team also states in their report that research has supported that 
some marine organisms, which internally form calcium carbonate 
skeletons, have an in-built mechanism to cope with ocean 
acidification. Professor Malcolm McCulloch of CoECRS and UWA states 
that most coral species appear to have the inner ability to buffer 
rising acidity of seawater and still build solid skeletons. "Marine 
organisms that form calcium carbonate skeletons generally produce it 
in one of two forms, known as aragonite and calcite," said McCulloch. 
"Our research broadly suggests that those with skeletons made of 
aragonite have the coping mechanism - while those that follow the 
calcite pathway generally do less well under more acidic conditions."



Despite the groundbreaking research, McCulloch also suggests that 
there is a small case of concern. The research team states in the 
report that coralline algae-the glue that sticks coral reefs 
together-appears to be vulnerable to rising acidification levels. 
Another cause of concern is that a large class of plankton, which is 
a significant tenet in the marine food web, is equally as vulnerable 
to the acidification as the coralline algae.



McCulloch said that the rising levels of carbon dioxide not only 
acidify the Earth's oceans, but also raise the ocean's temperatures. 
In turn, McCulloch states that warming oceans may increase the rates 
of coral growth, especially in corals now living in cooler waters. 
However, he said that a big question is to see whether or not corals 
can adapt to the current rate of global warming. "This is crucial 
since, if corals are bleached by the sudden arrival of hot ocean 
water and lose the symbiotic algae which are their main source of 
energy, they will still die," said McCulloch. "It's a more 
complicated picture, but broadly it means that there are going to be 
winners and losers in the oceans as its chemistry is modified by 
human activities - this could have the effect of altering major ocean 
ecosystems on which both we and a large part of marine life depend."



For more information, please visit: 
<http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1473.html>http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1473.html.

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No Rocks, No Water, No Ecosystem (EAS)
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E. A. Shinn, Courtesy Professor
University of South Florida
College of Marine Science Room 221A
140 Seventh Avenue South
St. Petersburg, FL 33701
<eshinn at marine.usf.edu>
Tel 727 553-1158---------------------------------- 
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