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Of all the consequences of global warming that I see mentioned in
the press, ocean acidification is the one that I find most
threatening. The planet has been at much higher concentrations of
CO2 before, so I wonder just how much of an impact it will have. It
may be large, I don't know. There is some hope that the oceans will
prove to be more resilient than we give them credit for, though.
Here is a link to a report about a study that was done on the Great
Barrier Reef that came out in the Brisbane Times on Friday:
<a class="moz-txt-link-freetext" href="http://www.brisbanetimes.com.au/queensland/why-climate-change-might-not-spell-death-for-the-reef-20120412-1wwdb.html">http://www.brisbanetimes.com.au/queensland/why-climate-change-might-not-spell-death-for-the-reef-20120412-1wwdb.html</a><br>
<br>
This study took a look at how coral is adapting to warmer
temperatures and changes in pH levels, and found that while some
species are having trouble, others are flourishing and adapting to
the changes. That leads me to believe that while the particular
species of oyster that the Whiskey Creek Shellfish Hatchery is using
may become unprofitable, there may be others that are actually
thriving. I guess I'll have to wait for someone to do a study
similar to the one described in the Brisbane Times on shellfish
along the Pacific coast first, though, in order to find out.<br>
<br>
Paul<br>
<br>
On 04/13/2012 04:23 PM, Ted Moffett wrote:
<blockquote
cite="mid:CAJ-QB6VKYAsd7wdM2KuN5S7YVz6eVWKGgRZHq1_bqEKR9JZUqg@mail.gmail.com"
type="cite">
<div>The dramatic decline in the Arctic, and impacts of ocean
acidification (as the following just published peer reviewed
science paper described lower down, as named in subject
heading, indicates), are but two among many impacts (increasing
floods, fires, drought and eventually faster rate of sea level
rise and species extinction) of human sourced CO2 emissions and
other human activities, that will only increase in magnitude if
we as a species do not profoundly alter course in a matter of
decades. </div>
<div> </div>
<div>Consider that the impacts we are already witnessing are with
only about 40% of the way towards a doubling of atmospheric CO2
level, from about 280 ppm pre-industrial to the current level
measured at the Mauna Loa site, ( <a moz-do-not-send="true"
href="http://www.esrl.noaa.gov/gmd/ccgg/trends/"
target="_blank">http://www.esrl.noaa.gov/gmd/ccgg/trends/</a>
) 394 ppm, which shows about at 2 ppm increase in the past
year. At this rate, in 83 years, before the end of this
century, humanity will have pushed atmospheric CO2 to about a
doubling over pre-industrial levels, to 560 ppm, and another
doubling will be underway. The total planetary reserves of
fossil fuels will allow us to go beyond the first doubling of
atmospheric CO2 level. </div>
<div> </div>
<div>Global average temperatures have increased about .8 C in the
GISS temperature record, </div>
<div>( <a moz-do-not-send="true"
href="http://data.giss.nasa.gov/gistemp/2011/Fig2.gif"
target="_blank">http://data.giss.nasa.gov/gistemp/2011/Fig2.gif</a> ) and
if this rate of temperature increase follows the rate of
potential atmospheric CO2 increase in a business as usual
scenario, we will reach over 2 C. increase in global average
temperatures by 2100, a level that many climate scientists think
will result in unmanageable global impacts, "tipping points", as
they say, such as meters of sea level rise from Greenland
destabilization. And of course, with increasing
industrialization and demand for energy, it is very possible
that human fossil fuel use and CO2 emissions will increase, thus
rates of atmospheric CO2 increase will increase, especially if
carbon sink reversal increases in magnitude. Thus it is also
within the range of significant scientific probability that
global average temperature increase will increase in rate,
especially given significant positive feedbacks, reduced albedo
from loss of ice cover, especially in the Arctic, among them.</div>
<div> </div>
<div>Good luck, kids! At 60 now, I certainly won't be around in
2100, without medical breakthroughs. But some born today will,
who will be about 88 in 2100. </div>
<div> </div>
<div>But what I find astonishing is the shrug I have witnesses
from the well educated in their middle years (30-50) who are
well aware that climate change is happening, who state that it
"won't impact them," but will impact the next generation.
Wrong! Climate change is already impacting us, and in a matter
of decades the impacts will significantly increase, so even for
someone 60, let alone 30-50, if they live to 90, not so
incredible, even they will witness increases in impacts,
by 2042.</div>
<div> -----------------------------------------------------</div>
<div><a moz-do-not-send="true"
href="http://www.aslo.org/lo/toc/vol_57/issue_3/0698.html"
target="_blank">http://www.aslo.org/lo/toc/vol_57/issue_3/0698.html</a></div>
<div>
<p>The Pacific oyster, <i>Crassostrea gigas</i>, shows negative
correlation to naturally elevated carbon dioxide levels:
Implications for near-term ocean acidification effects</p>
<p>Alan Barton, Burke Hales, George G. Waldbusser, Chris Langdon
and Richard A. Feely</p>
<p>Limnol. Oceanogr., 57(3), 2012, 698-710 | DOI:
10.4319/lo.2012.57.3.0698</p>
<p>
ABSTRACT: We report results from an oyster hatchery on the
Oregon coast, where intake waters experienced variable
carbonate chemistry (aragonite saturation state < 0.8 to
> 3.2; pH < 7.6 to > 8.2) in the early summer of
2009. Both larval production and midstage growth (∼ 120 to ∼
150 µm) of the oyster <i>Crassostrea gigas</i> were
significantly negatively correlated with the aragonite
saturation state of waters in which larval oysters were
spawned and reared for the first 48 h of life. The effects of
the initial spawning conditions did not have a significant
effect on early-stage growth (growth from D-hinge stage to ∼
120 µm), suggesting a delayed effect of water chemistry on
larval development.</p>
<p>--------------------------------------------</p>
<p><a moz-do-not-send="true"
href="http://www.sciencedaily.com/releases/2012/04/120411132219.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29"
target="_blank">http://www.sciencedaily.com/releases/2012/04/120411132219.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29</a></p>
<h1>Ocean Acidification Linked to Larval Oyster Failure</h1>
<div style="padding-bottom: 10px;">
<p><span>ScienceDaily (Apr. 11, 2012)</span> — Researchers at
Oregon State University have definitively linked an increase
in ocean acidification to the collapse of oyster seed
production at a commercial oyster hatchery in Oregon, where
larval growth had declined to a level considered by the
owners to be "non-economically viable."</p>
<p>A study by the researchers found that elevated seawater
carbon dioxide (CO<font><sub>2</sub>) levels, resulting in
more corrosive ocean water, inhibited the larval oysters
from developing their shells and growing at a pace that
would make commercial production cost-effective. As
atmospheric CO<sub>2</sub> levels continue to rise, this
may serve as the proverbial canary in the coal mine for
other ocean acidification impacts on shellfish, the
scientists say.</font></p>
<p>Results of the research have just been published in the
journal, <em>Limnology and Oceanography.</em></p>
<p>"This is one of the first times that we have been able to
show how ocean acidification affects oyster larval
development at a critical life stage," said Burke Hales, an
OSU chemical oceanographer and co-author on the study. "The
predicted rise of atmospheric CO<font><sub>2</sub> in the
next two to three decades may push oyster larval growth
past the break-even point in terms of production."</font></p>
<p>The owners of Whiskey Creek Shellfish Hatchery at Oregon's
Netarts Bay began experiencing a decline in oyster seed
production several years ago, and looked at potential causes
including low oxygen and pathogenic bacteria. Alan Barton,
who works at the hatchery and is an author on the journal
article, was able to eliminate those potential causes and
shifted his focus to acidification.</p>
<p>Barton sent samples to OSU and the National Oceanic and
Atmospheric Administration's Pacific Marine Environmental
Laboratory for analysis. Their ensuing study clearly linked
the production failures to the CO<font><sub>2</sub> levels
in the water in which the larval oysters are spawned and
spend the first 24 hours of their lives, the critical time
when they develop from fertilized eggs to swimming larvae,
and build their initial shells.</font></p>
<p>"The early growth stage for oysters is particularly
sensitive to the carbonate chemistry of the water," said
George Waldbusser, a benthic ecologist in OSU's College of
Earth, Ocean, and Atmospheric Sciences. "As the water
becomes more acidified, it affects the formation of calcium
carbonate, the mineral of which the shell material consists.
As the CO<font><sub>2</sub> goes up, the mineral stability
goes down, ultimately leading to reduced growth or
mortality."</font></p>
<p>Commercial oyster production on the West Coast of North
America generates more than $100 million in gross sales
annually, generating economic activity of some $273 million.
The industry has depended since the 1970s on oyster
hatcheries for a steady supply of the seed used by growers.
From 2007 to 2010, major hatcheries supplying the seed for
West Coast oyster growers suffered persistent production
failures.</p>
<p>The wild stocks of non-hatchery oysters simultaneously
showed low recruitment, putting additional strain on limited
seed supply.</p>
<p>Hales said Netarts Bay, where the Whiskey Creek hatchery is
located, experiences a wide range of chemistry fluctuations.
The OSU researchers say hatchery operators may be able to
adapt their operations to take advantage of periods when
water quality is at its highest.</p>
<p>"In addition to the impact of seasonal upwelling, the water
chemistry changes with the tidal cycle, and with the time of
day," Hales said. "Afternoon sunlight, for example, promotes
photosynthesis in the bay and that production can absorb
some of the carbon dioxide and lower the corrosiveness of
the water."</p>
<p>A previous study co-authored by Hales found the water that
is being upwelled in the Pacific Ocean off the Oregon coast
has been kept at depth away from the surface for about 50
years -- meaning it was last exposed to the atmosphere a
half-century ago, when carbon dioxide levels were much
lower. "Since atmospheric CO<font><sub>2</sub> levels have
risen significantly in the past half-century, it means
that the water that will be upwelled in the future will
become increasingly be more corrosive," Hales said.</font></p>
<p>The OSU researchers also found that larval oysters showed
delayed response to the water chemistry, which may cast new
light on other experiments looking at the impacts of
acidification on shellfish. In their study, they found that
larval oysters raised in water that was acidic, but
non-lethal, had significantly less growth in later stages of
their life.</p>
<p>"The takeaway message here is that the response to poor
water quality isn't always immediate," said Waldbusser. "In
some cases, it took until three weeks after fertilization
for the impact from the acidic water to become apparent.
Short-term experiments of just a few days may not detect the
damage."</p>
<p>The research has been funded by a grant from the National
Science Foundation, and supported by NOAA and the Pacific
Coast Shellfish Growers Association. Other authors on the
journal article include Chris Langdon, of OSU's Hatfield
Marine Science Center, and Richard Feely, of NOAA's Pacific
Marine Environmental Laboratories.</p>
<p>-----------------------------------------</p>
<p>Vision2020 Post: Ted Moffett</p>
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